Graham. wrote
RobertL wrote
Rod Speed wrote
Brian Gaff wrote
A.Lee wrote
DerekG wrote

It's a bit like trying to throw a Yo-Yo away whilst still
holding onto the string. And yes it's a crap plumbers idea.

It isnt. I've been on a training course that shows the graphs of
heat and gas used. The heated stats use less gas, and keep the
room at a steadier temperature than the standard on/off stats.

That though depends on the site of the stat, and how well designed
the placement of the radiators were in the first place.

Nope, you always get a benefit.

The only real downside is that the system switches more.

and doesn't warm up from cold so fast.

I don't follow.
Stat calls for heat.
Heater/boiler runs full pelt until setpoint is reached.
Stat turns off heat.

The earlier part of the thread is gone from the quoting now.

We were discussing why bi metallic strip mechanical
thermostats have a heater for the bi metallic strip.

They do that to reduce the hysteresis, and they reduce it by
heating the bi metallic strip with the heater when the load is on.

That means that they switch more often than a bi metallic strip
thermostat with no heater would.

That means they switch more, and do take longer to get up to
temperature when starting from cold, because they switch off
before the set point is reached, because the heater heats the
bi metallic strip.

They do however still get to the set point, they just dont stay
on all the time until the setpoint is reached when starting from cold.

On Tue, 06 Mar 2012 21:14:41 -0000, Rod Speed wrote:

Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote
Rod Speed wrote
Sure, but its likely to have been designed to handle motorised valves.

Shouldn't any stat handle one?

Not if it hasnt got magnetised contacts to provide a snap action.

Presumably then it shouldn't have a rating for inductive load? I'm sure it did.

Presumably another one from china. All bets are off with the 'ratiings' with those.

I once bought a laptop power supply from there, and the mains lead conductors were hair-thin, much like the very fine wire in the leads of Seinheiser (sp?) headphones. Also, within a few weeks, I managed to snap one of the prongs of the plug, simply by pulling the plug out of the socket at a slight angle (not violently either).

Bet you'll find if you actually compare the inductive
load with the rating that both exceed it by quite a bit.

The inductive rating I remember as being a couple of amps. It was not a 480 watt fan. It was 30 watts.

You cant just use the amps with inductive loads.

Then why do they state them?

They are chinese.

I've seen some very good stiff from China, it's not all cheap ****e.

it's measuring the combination of the room temperature and the output of the resistor.

Nope, not when the it turns on and the heater is off.

It doesnt do that when turning off either, when its turning
off, it isnt even using the air temp at all, the heater just
turns it off well before it would otherwise turn off to
significantly reduce the hysteresis.

THEN it measures the air temp again, with the resistor off.

Exactly.

Fraid not.

It's turning off when it shouldn't,

Nope, its turning off when it should to reduce the hysteresis.

therefore the heater is not on as long as it needs to be to keep the room warm.

Wrong, it just comes on again sooner and keeps the room more
evenly warm than otherwise, because of the reduced hysteresis.

STILL no guessing of the temperature.

The resistor has to cool before it will allow the heater to come back on.

I do.

You said you don't mind it being really warm though.

Thats a different effect to when its say 20C

So presumably varying from your minimum comfortable temperature to 4C higher wouldn't bother you?

It does bother me when its 4C colder than I prefer.

Why not set your room temperature so that you aren't near the minimum of your comfort zone?

There is no such thing. The temp I require varys with
what I am wearing and what I am doing etc etc etc.

Oh my god..... your life must be really complicated. Can you program your stat to change temp depending on what clothing you're wearing? You could fit radio tags in everything....

As I said most people have a zone of comfort, not one precise temperature.

If that was true, they wouldnt have been able to sell any of the bi metallic
strip thermostats for a higher price than the ones without heaters.

I reckon it's because people will pay more for something that says it's accurate. "Oh that must be good, look it's got a 0.5C accuracy!"

Like people buy a car that can go 150mph when they never go over the speed limit.

I would if I am wearing just a T shirt in the heated house.

Even if it's only for a minute?

Yep, because its a lot more than a minute in total
for the whole trip when going out shopping etc.

But most of the time you are in a heated car or a heated shop.

And I prefer not to feel too cold when moving
between the car in the carpark and the shop etc.

For a minute!!! ONE MINUTE!!!!

And I always take a top when flying, because they run the planes
too cold for my likely when wearing just a T shirt and shorts and
thongs/flip flops as I always do in spring/summer/autumn.

EGAD!

Corse when we are having one of those 10 days over
40C the plane can get ****ING hot on the ground when
they turn it off for refueling with the passenger still on
board at the intermediate stops with the Saab 340Bs.

How much hand luggage do you take on board? I can just imagine you changing clothes 5 times during the flight.

Surely the specific heat capacity of your body causes you to take a while to cool down.

Your core temp doesn't change. You feel the cold when
your skin temp drops significantly unless you are like that
mate of mine that wears shorts right thru the entire winter.

Your skin temp is irrelevant.

Not to my comfort it aint.

Even if you are stupid enough to lie down naked in
a snow drift,

Why is it stupid?

your core body temp wont be affected
but even you might feel a tad uncomfortable.

You'll be telling me you wash your hands in warm water next.

Another one doesnt go quite that far, but doesnt wear
much on top. He's pretty fat tho and I keep reminding him
that its his fat that keeps him warm, its a built in jacket.

I find fat people usually feel the cold more,

None of the ones I know do and one of them is by far the fattest person
I have ever seen in person,

It would depend on WHY they are fat I suppose.

even tho I have seen fatter ones in docos.

Gotta love the way Aussies put "O" on the end of stuff!

We all call him Huge for a reason.

Aren't you meant to say the opposite? "Lofty" is normally the nickname of a short person for example.

as they are fat due to a low metabolism.

Nope because they shovel more calories into their mouths than they burn.

He eats VASTLY more than any of the rest of us do.

He's one of the motorhomers and while everyone else
talks about particular towns about particular things unique
to that town, with him, thats where there is a pastry shop
with a particularly good line in cream cakes etc.

When he shows up to visit anyone, he usually brings a great
swag of that sort of thing. The others eat one or two each
and he wolfes down the vast bulk of what he brought.

Never seen anything like it.

Is he American or something?

Even he does wear a top when we are standing
around in the dark with a heavy frost at -10C for
an hour so outside with a decent wind.

The one who wears shorts right thru the winter doesnt show up that early.

I used to ride to school on a bike when I was a kid and in the depths
of winter, my ears felt like they might freeze off after the long downhill run. I wasnt stupid enough to do that
wearing just a T shirt and shorts.

That'll be why you're not used to it then. Kids these days are wrapped in cotton wool,

Try telling that that to my GP. His kid was showing
off to his mates riding his bike along the top of a
waist high wall at the school, fell off and broke is arm.

He should have done this: http://youtu.be/PBFHxBFQssk

I did once walk along the balcony wall in the theatre at my school. The headmaster went NUTS!

so when they get to adulthood, they're wimps.

Must be why they get killed surfing on car roofs etc.

Australia sounds more fun than here.

I actually take pff my fleece that I wear over a sweat over the T
shirt in winter when I go out in all but the most extreme weather.
I leave the fleece on in the most extreme weather and when doing
the garage/yard sale run in the depths of winter because the
regulars often stand around talking waiting for somewhere to open
and that can be damned cold, particularly with a heavy frost.

http://i0.kym-cdn.com/entries/icons/...4/facepalm.jpg

Stop crying boy, you some sort of bald sook ?

That was not a cry, that was a "facepalm".

SURE it was. Pity about the sobbing that blows that claim completely out of the water.

http://lmgtfy.com/?q=facepalm

Most choose to do what is most comfortable, including me.

The trouble is people are becoming worse.

The damned ancient greeks used to sit around in
their togas or whatever they wore and howl like that.

What?

You deaf ?

What are Greeks wearing togas to do with anything?

In a few more generations, we'll be wanting thermostats with a 0.1C accuracy, and we simply won't be able to go
outside at all.

We used to drive around in unheated cars in the
depth of winter and now arent that stupid anymore.

That change didnt actually produce the end
of civilisation as we know it for some reason.

It was unnecessary (apart from increasing driving visibility).

So are cars.

They perform a useful function, without them we would not be able to get form here to 200 miles away whenever we want/need to.

We are getting more and more expensive ways of being comfortable, and more and more things we won't have but are used
to when they fail.

You're always free to go back to a cave if you want.

There is a sensible middle ground.

Ever stopped to think how much money we spend on this comfort, and how much less work we'd have to do without it? Time off is the ultimate comfort.

Corse they fail too.

Less often.

Locally, no one did anything much special during the inevitable
10 days over 40C that happens many years. Now almost
everyone has at least an evaporative cooler, what the yanks
call a swamp cooler, and many have full airconditioning.

I can remember one car trip in conditions like that in a car
with no airconditioning at all. It was so ****ing hot that we
pulled up at a river and just jumped in the water and stayed
there in the shade in the water until the sun started to go down.

In those temps, wearing more clothes can be useful,

Nope. I built the house from scratch myself wearing just shorts, not even a T shirt.

with regular soakings of water. Lots of evaporation.

Doesnt work too well inside a car.

Open the windows when you drive along, much draught to allow the evaporation.

Yes, whipping yourself furiously when naked can help
a bit in winter, but I prefer to wear more clothes myself.

There are other more interesting things to do when naked.

When I go out for exercise, I try to anticipate what I will be
wearing at the end of the very long walk, because it irritates me
to have to have removed the sweat because the movement has warmed me up and the air has warmed up. I normally start
at first light, when its just light enough so I dont trip over stuff. I dont walk
around the streets, too boring, I normally walk in the bush/scrub
areas on the hills at the back of town for 1:30-2 hours.

I don't have to do that anticipation :-P

And arent as comfortable as me.

I don't notice the temperature.

You would with one of our 10 days over 40C

Nonsense. I adapt.

Its more than most's preferred comfort range which is
why heaters in bi metallic thermostats were invented.

The wouldnt bother with an extra cost item like that if
most dont prefer the reduced hysteresis that produces.

I doubt a resistor costs that much.

Still cost more than not having it.

It's probably more that un-knowledgable people will think they're
faulty if they have a 4C hysteresis and be liable to send them back.

Nope. Most prefer a lower hysteresis when it can be achieved that cheaply.

But I disagree on WHY they want it.

Irrelevant, they want it anyway.

That's my point. The resistor isn't there for the purpose you explained, it's there to make the customer feel good. They're just as likely to buy a chrome plated one without a resistor.

That wont fly either with the hot weather.

We routinely have 10 days over 40C,

If you lot got that much you'd be dying like flys.

I went to the South of France when they had that heatwave that killed hundreds of people. It didn't bother me. I
became
accustomed to it within a couple of days.

You'd be dead if you tried digging ditches in ours.

I'd get used to it.

Not even possible. People die if they are that stupid.

Only if they are wimpy like yourself.

As long as I was permitted to take my shirt off that is. And some drinks!

You'd still end up dead.

********.

One of the garage/yard salers wears shorts the entire year.

We routinely get heavy frosts at -10C and we are out at that time, in the dark.

No one else is that silly.

There are a few sensible people around. Wait till there's an ice age, then only people like him and me will
survive.

I'll be basking in the sun in my passive solar house pointing
at your frozen corpse in the snow drift and laughing.

Your house has been carted off by a glacier.

Not even possible here, too flat.

Something terrible would happen to it. Crushed by snow then.

That's what I hate about the UK, cloud. Rain is fine, sun is fine, but cloudy all the time is boring.

Yeah, even a very heavy frost is quite pleasant when its
sunny, particularly when I'm basking in it in my passive
solar house looking out over the oval of the school thats
quite close with the entire area bright white from the frost.

And observing kids falling over and cracking their skulls open :-)

Nar, their skulls are too thick for that |-)

[ROFL]

We don't get snow here.

Never missed skiing?

We do have much more skiable areas than you do, just not where I personally live.

Mountains covered in snow? In Australia?

No idea. I just noticed that when I was trying to find an decent summary of why bi metallic thermostats normally
have a heater, on the web.

My Golf (1998 model) does seem to keep PRECISELY at 90C on the guage. Older vehicles never used to do that. Maybe
it makes the engine more efficient, or produce less pollution,

Yeah, likely, I meant to say that and forgot to say it.

How do you find the Golf ? My previous was a 72, lasted 35+ years
until I was stupid enought to not bother to fix the windscreen leak that I kinew produced a wet floor when it rained
much until that eventually rusted a hole in the floor and was no longer registerable and not
economic to repair.

I have a hole in the floor too. I think it's from a leak in the sunroof.

It also has both locks busted, the radio-locking is broken, the passenger window doesn't work, the bonnet catch is
busted, and the rear washer is broken.

Sounds like the yanks are right, they've gone down hill a lot since mine.

It's no worse than any other car, I've come to the conclusion they are all pretty much the same now.

Like any other car there are little bits that go wrong that I don't bother fixing as they aren't really necessary.

That wasnt the case with mine over a much longer period than yours.

I don't tend to service or look after my cars.

And it hasnt happened with the Hyundai Getz I replaced it with either.

Not one warranty quibble in the 5 year warranty. Even the Golf didnt manage that.

Or the beetle that I had before the Golf either.

I only replaced that with the Golf because I had a ****ing
great Alsatian that was absolutely obsessed with having
his head out the window, even in the depths of winter
and on long trips lasting days at highway speeds.

Define highway speed :-)

The beetle only has one opening window on each side and in
summer the bugger used to slobber down the back of my neck.

That's one reason I never got a dog. That and having to walk it. And the ****.

The Golf fixed that, he got his own window and its got a heater
that allows him to have his way even in the depths of winter.

The heater is powerful enough to keep you at 30C while the window is open?

You'd reduce your heating costs quite a bit if you did.

I don't believe it would be that much. After all when I come back it has to warm the house back up.

Thats another very common misapprehension. Its just
basic physics that you lose significantly less at the house
lower temps, because loss is entirely determined by the
temperature differential all other factors kept constant.

I know. But if it's 0C outside, and the house cools from 20C to 17C, then it still has a similar difference.

You still save by turning it off when you arent there.

Not by much at all. 20C minus 0C is pretty much equal to 17C minus 0C.

And only a super insulated house will only drop
3C with it 0C outside if you are out all day.

It is well insulated. Double brick with foam insulation, double galzing, and fibreglass in the attic with wooden flooring on top, and boxes full of stuff on top of that.

If you do have a super insulated house, you dont need a boiler.

It cools until it eventually approaches the outdoor temperature of 0C, at which point the pipes freeze and stuff goes damp and mouldy.

If it's 10C outside, then the house wouldn't have cooled by much in that time period.

There is no need for any instantly, modern digital thermostats
anticipate the setpoint, now how long it takes to move between
the setpoints and just stop heating at the appropriate time at bed
time and start heating before the daytime setpoint in the morning
so when you get up, its at the temp you say you want.

That would be fine if you got up at an exact time every day.

Doesnt have to be exactly. If you set it for the earliest
time you normally get up, you still save significantly.

Although it would still be a problem - either the house is cooling
down before your bedtime,

Nope, it just stops heating then.

or you are going to bed with the house too warm.

Not if you have enough of a clue to have a different zone temp
for the bedroom from wherever you are before you go to bed.

Taint rocket science.

I don't wish to isolate parts of my house. It's a small house, and I tend to leave internal doors open for
convenience.

Hardly the end of civilisation as we know it to open the bedroom door once a day.

More than once a day. There's more than just a bed in there.

--
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The Web brings people together because no matter what kind of a twisted sexual mutant you happen to be, you've got millions of pals out there. Type in "Find people that have sex with goats that are on fire" and the computer will say "Specify type of goat." -- Rich Jeni

On Monday, March 5, 2012 9:36:16 AM UTC, Harry Bloomfield wrote:

If there were no natural air flow, without the heater resistor to
encourage it, then the thing would take forever to sense the falling
temperature when the stat opens. The fact is that it doesn't, because
there is air flow through the stat, irrespective of whether the
resistor is energised or not.


Right, so air moves around through the thermostat housing, although there's nothing causing it to move?

There may be adequate convection air currents in the vicinity of the thermostat in some cases, in others there won't.

There are air vents in the thermostat housing and a heater in the housing which will cause air movement.

Are you the same HarryRhondo/Alhoa who has been trolling my posts because I told him he was a dangerous, incompetent dickhead Or are you a different one?

On Monday, March 5, 2012 3:03:00 PM UTC, Graham. wrote:

The other thing Onetap might consider is that the resistor body is
physically in contact with strip (at least it is on this old Satchwell
I have on the desk), so the design was to heat the strip by conduction
primarily.

So the resistor is in contact with the bi-mettalic strip. The bi-metallic strip dissipates the heat to the air by convection and to the surroundings by radiation. The convection causes air currents to pass through the air vents. Anyone still having difficulty with that one? I don't think it's that hard to grasp.

The fact that the heater is only on when the load is has probably got something to do with the high thermal capacity of the metal and the high radiant emissivity of the metal surfaces. Metal surfaces are usually colder than the air temperature, and usually are the first to attract condensation. Then again, I didn't design the things and have never used one. Some control technicians thought the heater was effective for some applications..

Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote
Rod Speed wrote

Sure, but its likely to have been designed to handle motorised valves.

Shouldn't any stat handle one?

Not if it hasnt got magnetised contacts to provide a snap action.

Presumably then it shouldn't have a rating for inductive load? I'm sure it did.

Presumably another one from china. All bets are off with the 'ratiings' with those.

I once bought a laptop power supply from there, and the mains lead conductors were hair-thin, much like the very fine
wire in the leads of Seinheiser (sp?) headphones. Also, within a few weeks, I managed to snap one of the prongs of
the plug, simply by pulling the plug out of the socket at a slight angle (not violently either).

And then there are those who had their pets killed by pet food from china.

And the chinese kids who died because some complete
arseholes were chucking melamine in the milk because
that increase the protien test results they were paid on.;

Bet you'll find if you actually compare the inductive
load with the rating that both exceed it by quite a bit.

The inductive rating I remember as being a couple of amps. It was not a 480 watt fan. It was 30 watts.

You cant just use the amps with inductive loads.

Then why do they state them?

They are chinese.

I've seen some very good stiff from China, it's not all cheap ****e.

Yeah, I buy most of the electronics I buy from there.

Not just electronics either. I bought some nail clippers for quite literally
1c, including postage which looked exactly like what I had lost.

They did turn out to be identical but the jaws didnt close properly,
didnt close squarely, so were useless. I told him that by email,
expected to be ignored because I had paid 1c but it didnt cost
anything to email him. He sent me another for free, and it was perfect.

it's measuring the combination of the room temperature and the output of the resistor.

Nope, not when the it turns on and the heater is off.

It doesnt do that when turning off either, when its turning
off, it isnt even using the air temp at all, the heater just
turns it off well before it would otherwise turn off to
significantly reduce the hysteresis.

THEN it measures the air temp again, with the resistor off.

Exactly.

Fraid not.

It's turning off when it shouldn't,

Nope, its turning off when it should to reduce the hysteresis.

therefore the heater is not on as long as it needs to be to keep
the room warm.

Wrong, it just comes on again sooner and keeps the room more
evenly warm than otherwise, because of the reduced hysteresis.

STILL no guessing of the temperature.

The resistor has to cool before it will allow the heater to come back on.

Sure but thats a minor part of the on/off ratio and you get a lower hysteresis anyway.

So it does what its designed to do very effectively indeed for peanuts.

You're always welcome to use a proper modern digital thermostat
for more money if you dont like the quirks inevitable with that design.

I do.

You said you don't mind it being really warm though.

Thats a different effect to when its say 20C

So presumably varying from your minimum comfortable temperature to 4C higher wouldn't bother you?

It does bother me when its 4C colder than I prefer.

Why not set your room temperature so that you aren't near the minimum of your comfort zone?

There is no such thing. The temp I require varys with
what I am wearing and what I am doing etc etc etc.

Oh my god..... your life must be really complicated.

Nope.

Can you program your stat to change temp depending on what clothing you're wearing?

I do it the other way, I wear what suits what its programmed to temp wise.

You could fit radio tags in everything....

Easier to wear what suits what its programmed to.

As I said most people have a zone of comfort, not one precise temperature.

If that was true, they wouldnt have been able to sell any of the bi
metallic strip thermostats for a higher price than the ones without heaters.

I reckon it's because people will pay more for something that says it's accurate.

I cant say I have ever seen a thermostat sold like that.

And few consumers buy thermostats anyway, they
usually come with the central heating they order.

"Oh that must be good, look it's got a 0.5C accuracy!"

Cant say I have ever seen a thermostat advertise an accuracy either.

Its just not possible, the accuracy you end up with depends on where its
located, how lossy the place being heated is, how responsive the heating
system is, whether you hold you mouth just right, whether you can monster
the kids into shutting the door when they tear in and out etc etc etc.

Like people buy a car that can go 150mph when they never go over the speed limit.

I doubt too many buy the car based on the top speed it can do.

I would if I am wearing just a T shirt in the heated house.

Even if it's only for a minute?

Yep, because its a lot more than a minute in total
for the whole trip when going out shopping etc.

But most of the time you are in a heated car or a heated shop.

And I prefer not to feel too cold when moving
between the car in the carpark and the shop etc.

For a minute!!! ONE MINUTE!!!!

Its more than one minute in the whole trip.

And I always take a top when flying, because they run the planes
too cold for my likely when wearing just a T shirt and shorts and
thongs/flip flops as I always do in spring/summer/autumn.

EGAD!

You can swoon now, we'll try not to laugh...

Corse when we are having one of those 10 days over
40C the plane can get ****ING hot on the ground when
they turn it off for refueling with the passenger still on
board at the intermediate stops with the Saab 340Bs.

How much hand luggage do you take on board?

Normally nothing. I deliberately take one of the smaller paperback
that fit in a pocket.

I can just imagine you changing clothes 5 times during the flight.

You were warned about those magic mushrooms...

Surely the specific heat capacity of your body causes you to take a while to cool down.

Your core temp doesn't change. You feel the cold when
your skin temp drops significantly unless you are like that
mate of mine that wears shorts right thru the entire winter.

Your skin temp is irrelevant.

Not to my comfort it aint.

Even if you are stupid enough to lie down naked in a snow drift,

Why is it stupid?

If you have to ask...

your core body temp wont be affected
but even you might feel a tad uncomfortable.

You'll be telling me you wash your hands in warm water next.

Fraid not, cold water suits me fine.

I'm not into cold showers tho, even in the middle of those 10 days over 40C

Another one doesnt go quite that far, but doesnt wear
much on top. He's pretty fat tho and I keep reminding him
that its his fat that keeps him warm, its a built in jacket.

I find fat people usually feel the cold more,

None of the ones I know do and one of them is by far the fattest person I have ever seen in person,

It would depend on WHY they are fat I suppose.

Yep, and I told you why he is.

even tho I have seen fatter ones in docos.

Gotta love the way Aussies put "O" on the end of stuff!

Quite few burst a blood vessel when I talk about Japs.

We all call him Huge for a reason.

Aren't you meant to say the opposite?

Nope. We do with some, like bluey for a red haired person,
tho they are now called rangas. Short for orangutan.

Thats what our current Prime Minister gets called, she's pom.

"Lofty" is normally the nickname of a short person for example.

I call kids midgets. That REALLY lights their fire.

as they are fat due to a low metabolism.

Nope because they shovel more calories into their mouths than they burn.

He eats VASTLY more than any of the rest of us do.

He's one of the motorhomers and while everyone else
talks about particular towns about particular things unique
to that town, with him, thats where there is a pastry shop
with a particularly good line in cream cakes etc.

When he shows up to visit anyone, he usually brings a great
swag of that sort of thing. The others eat one or two each
and he wolfes down the vast bulk of what he brought.

Never seen anything like it.

Is he American or something?

Nope, born here.

Even he does wear a top when we are standing
around in the dark with a heavy frost at -10C for
an hour so outside with a decent wind.

The one who wears shorts right thru the winter doesnt show up that early.

I used to ride to school on a bike when I was a kid and in the
depths of winter, my ears felt like they might freeze off after the long downhill run. I wasnt stupid enough to do
that wearing just a T shirt and shorts.

That'll be why you're not used to it then. Kids these days are wrapped in cotton wool,

Try telling that that to my GP. His kid was showing
off to his mates riding his bike along the top of a
waist high wall at the school, fell off and broke is arm.

He should have done this: http://youtu.be/PBFHxBFQssk

He's too stupid for that.

He came very close indeed to a retrospective abortion when
on another occassiion he was showing off to his mates how
much he knew about PCs by deleting files at random on his
dads PC that his dad used to keep all is patient records on.

Needless to say, no backups. That was in the days when
floppys were the only backup feasible even for a doctor.

I did once walk along the balcony wall in the theatre at my school. The headmaster went NUTS!

Yeah, we've had a craze of 'planking' with stupid kids
doing that on balcony walls way up on multistory buildings.

A few have been winners of the Darwin award.

so when they get to adulthood, they're wimps.

Must be why they get killed surfing on car roofs etc.

Australia sounds more fun than here.

I've seen some of yours doing stuff like that in one of those doco
series that I forget the name of 'craziest stuff of all time etc'

Presumably plenty of it on youtube.

I actually take pff my fleece that I wear over a sweat over the T
shirt in winter when I go out in all but the most extreme weather. I leave the fleece on in the most extreme
weather and when doing
the garage/yard sale run in the depths of winter because the
regulars often stand around talking waiting for somewhere to open
and that can be damned cold, particularly with a heavy frost.

http://i0.kym-cdn.com/entries/icons/...4/facepalm.jpg

Stop crying boy, you some sort of bald sook ?

That was not a cry, that was a "facepalm".

SURE it was. Pity about the sobbing that blows that claim completely out of the water.

http://lmgtfy.com/?q=facepalm

Fools no one. You cant hide the sobbing, boy.

Most choose to do what is most comfortable, including me.

The trouble is people are becoming worse.

The damned ancient greeks used to sit around in
their togas or whatever they wore and howl like that.

What?

You deaf ?

What are Greeks wearing togas to do with anything?

It wasnt what are wearing that matters, stupid.

And stop sobbing. You're lowering the tone, again.

In a few more generations, we'll be wanting thermostats with a
0.1C accuracy, and we simply won't be able to go outside at all.

We used to drive around in unheated cars in the
depth of winter and now arent that stupid anymore.

That change didnt actually produce the end
of civilisation as we know it for some reason.

It was unnecessary (apart from increasing driving visibility).

So are cars.

They perform a useful function, without them we would not be able to get form here to 200 miles away whenever we
want/need to.

So do thermostats, even you have one.

We are getting more and more expensive ways of being comfortable,
and more and more things we won't have but are used to when they fail.

You're always free to go back to a cave if you want.

There is a sensible middle ground.

Yep proper modern digital thermostats.

Even you can have one if you'd just stop that pathetic sobbing.

Ever stopped to think how much money we spend on this comfort, and how much less work we'd have to do without it?

You're always free to smash ever thermostat you
own, and then take to the boiler with an axe etc.

Corse you might have to spend a night in the cells when the plods
show up with the funky canvas jacket with the extremely long sleeves.

Feel free to call me, I'm used to getting calls from the loony bin.

Time off is the ultimate comfort.

Depends on how much you like what you are doing.

You can make a case that by far the best arrangement is
when someone is actually stupid enough to pay you very
well indeed for doing what you would happily do for free.

Corse they fail too.

Less often.

My house doesnt fail often enough to matter.

Niether does my car.

Locally, no one did anything much special during the inevitable
10 days over 40C that happens many years. Now almost
everyone has at least an evaporative cooler, what the yanks
call a swamp cooler, and many have full airconditioning.

I can remember one car trip in conditions like that in a car
with no airconditioning at all. It was so ****ing hot that we
pulled up at a river and just jumped in the water and stayed
there in the shade in the water until the sun started to go down.

In those temps, wearing more clothes can be useful,

Nope. I built the house from scratch myself wearing just shorts, not even a T shirt.

with regular soakings of water. Lots of evaporation.

Doesnt work too well inside a car.

Open the windows when you drive along, much draught to allow the evaporation.

The seats go mouldy.

Yes, whipping yourself furiously when naked can help
a bit in winter, but I prefer to wear more clothes myself.

There are other more interesting things to do when naked.

A likely story. I know about you poms.

When I go out for exercise, I try to anticipate what I will be
wearing at the end of the very long walk, because it irritates me to have to have removed the sweat because the
movement has warmed me up and the air has warmed up. I normally start at first light, when its just light enough
so I dont trip over stuff. I dont walk around the streets, too boring, I normally walk in the bush/scrub areas
on the hills at the back of town for 1:30-2 hours.

I don't have to do that anticipation :-P

And arent as comfortable as me.

I don't notice the temperature.

You would with one of our 10 days over 40C

Nonsense. I adapt.

Not even possible.

And you clearly dont, you heat your house.

Its more than most's preferred comfort range which is
why heaters in bi metallic thermostats were invented.

The wouldnt bother with an extra cost item like that if
most dont prefer the reduced hysteresis that produces.

I doubt a resistor costs that much.

Still cost more than not having it.

It's probably more that un-knowledgable people will think they're
faulty if they have a 4C hysteresis and be liable to send them back.

Nope. Most prefer a lower hysteresis when it can be achieved that cheaply.

But I disagree on WHY they want it.

Irrelevant, they want it anyway.

That's my point. The resistor isn't there for the purpose you explained, it's there to make the customer feel good.

**** all of the customers ever knew it was there.

They're just as likely to buy a chrome plated one without a resistor.

Nope, because you cant buy them anymore.

Because no one is actually stupid enough to demand those.

That wont fly either with the hot weather.

We routinely have 10 days over 40C,

If you lot got that much you'd be dying like flys.

I went to the South of France when they had that heatwave that killed hundreds of people. It didn't bother me. I
became
accustomed to it within a couple of days.

You'd be dead if you tried digging ditches in ours.

I'd get used to it.

Not even possible. People die if they are that stupid.

Only if they are wimpy like yourself.

Cant be wimpy if I built my house in those conditions.

As long as I was permitted to take my shirt off that is. And some drinks!

You'd still end up dead.

********.

Its happened. Plenty of you poms have ended up dead here that way.

One of the garage/yard salers wears shorts the entire year.

We routinely get heavy frosts at -10C and we are out at that
time, in the dark.

No one else is that silly.

There are a few sensible people around. Wait till there's an ice age, then only people like him and me will
survive.

I'll be basking in the sun in my passive solar house pointing
at your frozen corpse in the snow drift and laughing.

Your house has been carted off by a glacier.

Not even possible here, too flat.

Something terrible would happen to it.

Nope.

Crushed by snow then.

Not even possible.

That's what I hate about the UK, cloud. Rain is fine, sun is fine, but cloudy all the time is boring.

Yeah, even a very heavy frost is quite pleasant when its
sunny, particularly when I'm basking in it in my passive
solar house looking out over the oval of the school thats
quite close with the entire area bright white from the frost.

And observing kids falling over and cracking their skulls open :-)

Nar, their skulls are too thick for that |-)

[ROFL]

We don't get snow here.

Never missed skiing?

We do have much more skiable areas than you do, just not where I
personally live.

Mountains covered in snow? In Australia?

Yep. They might just be called the Snowy Mountains for a reason.

Bigger area than the whole of Britain in fact.

I wont call it a soggy little island again, otherwise
we will have more of that wimpy sobbing from you.

No idea. I just noticed that when I was trying to find an decent summary of why bi metallic thermostats normally
have a heater, on the web.

My Golf (1998 model) does seem to keep PRECISELY at 90C on the guage. Older vehicles never used to do that. Maybe
it makes the engine more efficient, or produce less pollution,

Yeah, likely, I meant to say that and forgot to say it.

How do you find the Golf ? My previous was a 72, lasted 35+ years until I was stupid enought to not bother to fix
the windscreen
leak that I kinew produced a wet floor when it rained much until
that eventually rusted a hole in the floor and was no longer
registerable and not economic to repair.

I have a hole in the floor too. I think it's from a leak in the sunroof.

It also has both locks busted, the radio-locking is broken, the
passenger window doesn't work, the bonnet catch is busted, and the rear washer is broken.

Sounds like the yanks are right, they've gone down hill a lot since mine.

It's no worse than any other car,

Its a hell of a lot worse than my Getz. Nothing has come off that
except the aerial I took off because I park it under the trees and
I was too lazy to trim the trees and it used to catch on that.

I've come to the conclusion they are all pretty much the same now.

Fraid not.

Like any other car there are little bits that go wrong that I don't bother fixing as they aren't really necessary.

That wasnt the case with mine over a much longer period than yours.

I don't tend to service or look after my cars.

Yeah, I dont either. The Golf only ever had one oil change in its entire life.

I did get the free one with the Getz but havent bothered with one since.

And it hasnt happened with the Hyundai Getz I replaced it with either.

Not one warranty quibble in the 5 year warranty. Even the Golf didnt manage that.

Or the beetle that I had before the Golf either.

I only replaced that with the Golf because I had a ****ing
great Alsatian that was absolutely obsessed with having
his head out the window, even in the depths of winter
and on long trips lasting days at highway speeds.

Define highway speed :-)

140KM/Hour in my case.

Hilarious, you could watch him try to bite the semis going
past in the opposite direction in the driver's wing mirror.

He never actually managed to catch one.

The beetle only has one opening window on each side and in
summer the bugger used to slobber down the back of my neck.

That's one reason I never got a dog. That and having to walk it.

I walk anyway.

And the ****.

I used to just mow it, can be quite spectacular when the dog lives
on dried dog food, quite a bit neveer gets digested and goes right thru.

Dont bother to mow anymore, the jungle is only waist high, nothing to worry about.

The Golf fixed that, he got his own window and its got a heater
that allows him to have his way even in the depths of winter.

The heater is powerful enough to keep you at 30C while the window is open?

Didnt bother to measure, certainly warm enough so he was free to do what he wanted.

Corse he was such a massive great dog across the chest that there wasnt
actually a huge amount of open window even with it wound right down.

You'd reduce your heating costs quite a bit if you did.

I don't believe it would be that much. After all when I come back it has to warm the house back up.

Thats another very common misapprehension. Its just
basic physics that you lose significantly less at the house
lower temps, because loss is entirely determined by the
temperature differential all other factors kept constant.

I know. But if it's 0C outside, and the house cools from 20C to 17C, then it still has a similar difference.

You still save by turning it off when you arent there.

Not by much at all. 20C minus 0C is pretty much equal to 17C minus 0C.

I dont buy the 17.

And only a super insulated house will only drop
3C with it 0C outside if you are out all day.

It is well insulated. Double brick with foam insulation, double
galzing, and fibreglass in the attic with wooden flooring on top, and boxes full of stuff on top of that.

Sure, but thats not super insulated.

If it really was super insulated, you wouldnt need a boiler.

If you do have a super insulated house, you dont need a boiler.

It cools until it eventually approaches the outdoor temperature of 0C,

Not if its super insulated and there are people living in it.

at which point the pipes freeze and stuff goes damp and mouldy.

Nope, it need to get well below that for that to happen.

And if it really was super insulated, even just a 100W light bulb would ensure
that the pipes never froze even if you were away for the whole of the winter.

If it's 10C outside, then the house wouldn't have cooled by much in that time period.

There is no need for any instantly, modern digital thermostats
anticipate the setpoint, now how long it takes to move between
the setpoints and just stop heating at the appropriate time at bed time and start heating before the daytime
setpoint in the morning
so when you get up, its at the temp you say you want.

That would be fine if you got up at an exact time every day.

Doesnt have to be exactly. If you set it for the earliest
time you normally get up, you still save significantly.

Although it would still be a problem - either the house is cooling down before your bedtime,

Nope, it just stops heating then.

or you are going to bed with the house too warm.

Not if you have enough of a clue to have a different zone temp
for the bedroom from wherever you are before you go to bed.

Taint rocket science.

I don't wish to isolate parts of my house. It's a small house, and
I tend to leave internal doors open for convenience.

Hardly the end of civilisation as we know it to open the bedroom door once a day.

More than once a day. There's more than just a bed in there.

"Rod Speed" wrote in message
...
Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote
Rod Speed wrote

large snip

And the award for patience in the line of ****ing stupidity goes to Rod
Speed. His responses are far beyond the call of duty and he deserves to be
heralded as a uk.d-i-y top-gun. Against all odds he selflessly attempted to
explain the operation of heated thermostats to a degree level scientist,
(without success). Apprenticeships just 'aint what they used to be.

Onetap wrote
Graham. wrote

The other thing Onetap might consider is that the resistor body
is physically in contact with strip (at least it is on this old Satchwell
I have on the desk), so the design was to heat the strip
by conduction primarily.

So the resistor is in contact with the bi-mettalic strip. The
bi-metallic strip dissipates the heat to the air by convection
and to the surroundings by radiation. The convection causes
air currents to pass through the air vents. Anyone still having
difficulty with that one? I don't think it's that hard to grasp.

Different matter entirely to why the heater is there at all and why
bi metallic strip thermostats work fine if you disconnect the heater.

The ONLY effect you get when you do that is that the hystersis increases.

You do NOT get a set point shift.

The fact that the heater is only on when the load is has probably
got something to do with the high thermal capacity of the metal
and the high radiant emissivity of the metal surfaces.

Nope, nothing to do with that at all.

It actually allows the bi metallic strip to see what the temperature of the air is.

Metal surfaces are usually colder than the air temperature,

Not even possible.

and usually are the first to attract condensation.

Thats wrong too.

Then again, I didn't design the things and have never used one.

Thats always been obvious.

Some control technicians thought the heater was effective for some applications..

And its completely trivial to prove that the heater does reduce the
hysteresis as it was designed to do by whoever invented that approach.

They wouldnt add an extra cost item like that if it didnt do something;

Onetap wrote :
Right, so air moves around through the thermostat housing, although there's
nothing causing it to move?

There may be adequate convection air currents in the vicinity of the
thermostat in some cases, in others there won't.

There are air vents in the thermostat housing and a heater in the housing
which will cause air movement.

I cannot think of any circumstance where there would not be a flow of
air through a thermostat, without need of an internal heater to
encourage the flow.

Air will always either flow up a wall surface or down it, depending
upon whether the wall is warmer than the air or cooler than it. In the
process of moving along the wall, it must pass through the stat..

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Rod Speed has brought this to us :
Onetap wrote
Graham. wrote

The other thing Onetap might consider is that the resistor body
is physically in contact with strip (at least it is on this old Satchwell
I have on the desk), so the design was to heat the strip
by conduction primarily.

So the resistor is in contact with the bi-mettalic strip. The
bi-metallic strip dissipates the heat to the air by convection
and to the surroundings by radiation. The convection causes
air currents to pass through the air vents. Anyone still having
difficulty with that one? I don't think it's that hard to grasp.

Different matter entirely to why the heater is there at all and why
bi metallic strip thermostats work fine if you disconnect the heater.

The ONLY effect you get when you do that is that the hystersis increases.

You do NOT get a set point shift.

The fact that the heater is only on when the load is has probably
got something to do with the high thermal capacity of the metal
and the high radiant emissivity of the metal surfaces.

Nope, nothing to do with that at all.

It actually allows the bi metallic strip to see what the temperature of the
air is.

Metal surfaces are usually colder than the air temperature,

Not even possible.

and usually are the first to attract condensation.

Thats wrong too.

Then again, I didn't design the things and have never used one.

Thats always been obvious.

Some control technicians thought the heater was effective for some
applications..

And its completely trivial to prove that the heater does reduce the
hysteresis as it was designed to do by whoever invented that approach.

They wouldnt add an extra cost item like that if it didnt do something;

You are wasting your time with providing explanations to this poster!

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Rod Speed was thinking very hard :
The earlier part of the thread is gone from the quoting now.

We were discussing why bi metallic strip mechanical
thermostats have a heater for the bi metallic strip.

They do that to reduce the hysteresis, and they reduce it by
heating the bi metallic strip with the heater when the load is on.

That means that they switch more often than a bi metallic strip
thermostat with no heater would.

That means they switch more, and do take longer to get up to
temperature when starting from cold, because they switch off
before the set point is reached, because the heater heats the
bi metallic strip.

They do however still get to the set point, they just dont stay
on all the time until the setpoint is reached when starting from cold.

That is not what my graphs from when we had a mechanical stat show.
They show an almost constant heating run, until the set point is
reached, then several short rapid boiler runs, as heat is absorbed by
the fabric. Once the fabric is up to temperature the graph settles down
to a more leisurely pace.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Wednesday, March 7, 2012 9:06:32 AM UTC, Harry Bloomfield wrote:


Air will always either flow up a wall surface or down it, depending
upon whether the wall is warmer than the air or cooler than it. In the
process of moving along the wall, it must pass through the stat..


I cannot think of any circumstance where there would not be a flow of
air through a thermostat, without need of an internal heater to
encourage the flow.

Wall surface is approximately the same temperature as the air = No/negligible heat transfer between the wall and the air = no/inadequate convection air currents along the the wall.

Ther sarcasm in the previous post went way over your head. Mr Newton says you have to have an energy input to move (or accelerate) mass. If there's no fan and heat differences to cause convection, what moves the air through the thermostat?

Harry Bloomfield wrote
Rod Speed wrote
Onetap wrote
Graham. wrote

The other thing Onetap might consider is that the resistor body
is physically in contact with strip (at least it is on this old
Satchwell I have on the desk), so the design was to heat the strip
by conduction primarily.

So the resistor is in contact with the bi-mettalic strip. The
bi-metallic strip dissipates the heat to the air by convection
and to the surroundings by radiation. The convection causes
air currents to pass through the air vents. Anyone still having
difficulty with that one? I don't think it's that hard to grasp.

Different matter entirely to why the heater is there at all and why
bi metallic strip thermostats work fine if you disconnect the heater.

The ONLY effect you get when you do that is that the hystersis increases.

You do NOT get a set point shift.

The fact that the heater is only on when the load is has probably
got something to do with the high thermal capacity of the metal
and the high radiant emissivity of the metal surfaces.

Nope, nothing to do with that at all.

It actually allows the bi metallic strip to see what the temperature of the air is.

Metal surfaces are usually colder than the air temperature,

Not even possible.

and usually are the first to attract condensation.

Thats wrong too.

Then again, I didn't design the things and have never used one.

Thats always been obvious.

Some control technicians thought the heater was effective for some applications..

And its completely trivial to prove that the heater does reduce the
hysteresis as it was designed to do by whoever invented that approach.

They wouldnt add an extra cost item like that if it didnt do something;

You are wasting your time with providing explanations to this poster!

True, but I do that in case anyone considers that he might be right.

And you did so yourself too.

On Wednesday, March 7, 2012 3:25:31 AM UTC, Rod Speed wrote:

The ONLY effect you get when you do that is that the hystersis increases.

You do NOT get a set point shift.

The sensing element, the bi-metallic strip, responds to the temperature of the bi-metallic strip. You think that you have an electric heater attached or adjacent to the bi-metallic strip and it doesn't affect the temperature of the bi-metallic strip. How very quaint.


The fact that the heater is only on when the load is has probably
got something to do with the high thermal capacity of the metal
and the high radiant emissivity of the metal surfaces.

Nope, nothing to do with that at all.

It actually allows the bi metallic strip to see what the temperature of the air is.

Metal surfaces are usually colder than the air temperature,

Not even possible.

You don't think so? So, you think that the metal temperature will always equal the air temperature?

That is so far removed from reality that I'm not even going to try to correct your ignorance.



Thats wrong too.

No, it's correct.

Then again, I didn't design the things and have never used one.

Thats always been obvious.

Yes, all my controls experience has involved thermistor temperature sensors..


And its completely trivial to prove that the heater does reduce the
hysteresis as it was designed to do by whoever invented that approach.

They wouldnt add an extra cost item like that if it didnt do something;

You seem to be hard of understanding. You should have an argument with the person who said it didn't reduce the hysteresis. You haven't noticed that it wasn't me. IT does that partly by inducing convection air flow through the thermostat housing.

Harry Bloomfield wrote
Rod Speed wrote

The earlier part of the thread is gone from the quoting now.

We were discussing why bi metallic strip mechanical
thermostats have a heater for the bi metallic strip.

They do that to reduce the hysteresis, and they reduce it by
heating the bi metallic strip with the heater when the load is on.

That means that they switch more often than a bi metallic strip thermostat with no heater would.

That means they switch more, and do take longer to get up to
temperature when starting from cold, because they switch off
before the set point is reached, because the heater heats the
bi metallic strip.

They do however still get to the set point, they just dont stay on all the time until the setpoint is reached when
starting from cold.

That is not what my graphs from when we had a mechanical stat show.
They show an almost constant heating run, until the set point is reached,

Cant see how thats possible with a bi metallic strip thermostat with a heater.

Maybe the heater wasnt actually connected properly so there was no heater.

then several short rapid boiler runs, as heat is absorbed by the fabric.

I'd expect more than several. Whats the fabric ?

Once the fabric is up to temperature the graph settles down to a more leisurely pace.

On Wednesday, March 7, 2012 9:06:32 AM UTC, Harry Bloomfield wrote:
Onetap :

You didn't answer the question, Harry.

Are you the Rhondo aka Alhoa aka Harry who was responsible for this?

http://www.diynot.com/forums/viewtop...770026#1770026

Why did you delete the pictures from that post , they were really, erm, interesting?

I think I upset that Harry by informing him that his '3-port valve' was a piece of tat.

Onetap wrote
Harry Bloomfield wrote

Air will always either flow up a wall surface or down it, depending
upon whether the wall is warmer than the air or cooler than it. In
the process of moving along the wall, it must pass through the stat..

I cannot think of any circumstance where there would not be a flow of air
through a thermostat, without need of an internal heater to encourage the flow.

Wall surface is approximately the same temperature as the air

Wrong. The heat can only be leaving via the walls and roof and floor.

= No/negligible heat transfer between the wall and the air

Even sillier.

= no/inadequate convection air currents along the the wall.

You can see it with suitable thermal imaging.

Ther sarcasm in the previous post went way over your head.
Mr Newton says you have to have an energy input to move
(or accelerate) mass. If there's no fan and heat differences
to cause convection, what moves the air through the thermostat?

The air flowing up or down the wall, as he said.

Onetap wrote
Rod Speed wrote

The ONLY effect you get when you do that is that the hystersis increases.

You do NOT get a set point shift.

The sensing element, the bi-metallic strip, responds
to the temperature of the bi-metallic strip.

Mindlessly silly.

You think that you have an electric heater attached or adjacent to the
bi-metallic strip and it doesn't affect the temperature of the bi-metallic strip.

Not when it isnt being heated it doesnt.

How very quaint.

Harry Blomfield is right.

The fact that the heater is only on when the load is has probably
got something to do with the high thermal capacity of the metal
and the high radiant emissivity of the metal surfaces.

Nope, nothing to do with that at all.

It actually allows the bi metallic strip to see what the temperature of the air is.

Metal surfaces are usually colder than the air temperature,

Not even possible.

You don't think so?

I know so.

So, you think that the metal temperature will always equal the air temperature?

Nope.

That is so far removed from reality that I'm not even going to try to correct your ignorance.

Having fun thrashing that straw man ?

Thats wrong too.

No, it's correct.

Nope.

Then again, I didn't design the things and have never used one.

Thats always been obvious.

Yes, all my controls experience has involved thermistor temperature sensors.

And you dont have a clue about even the most basic physics.

And its completely trivial to prove that the heater does reduce the
hysteresis as it was designed to do by whoever invented that approach.

They wouldnt add an extra cost item like that if it didnt do something;

You seem to be hard of understanding.

Then you need to get your seems machinery seen to, bad.

You should have an argument with the person
who said it didn't reduce the hysteresis.

No one said that.

You haven't noticed that it wasn't me.

Wrong, as always.

IT does that partly by inducing convection
air flow through the thermostat housing.

Have fun explaining why its turned off when the load is off.

If it was there so there is convection thru the thermostat,
it would be on all the time. It isnt. You are just plain wrong.

On Wednesday, March 7, 2012 10:01:48 AM UTC, Rod Speed wrote:

The sensing element, the bi-metallic strip, responds
to the temperature of the bi-metallic strip.

Mindlessly silly.

A simple fact that you haven't managed to grasp.

The sensing element or transducer relies on heat transfer to & from the medium to provide a temperature measurement. In this case we want to measure air temperature, the heat transfer to & from metal to air is mostly by convection and there is a heater inside the thermostat which will cause convection. Is that a co-incidence?


Harry Blomfield is right.

Are you Harry? Quite probably.

Straw man? Who was the other troll who was fond of that phrase?
I shall never care.

On Wednesday, March 7, 2012 9:51:14 AM UTC, Rod Speed wrote:
Onetap wrote
Harry Bloomfield wrote


I cannot think of any circumstance where there would not be a flow of air
through a thermostat, without need of an internal heater to encourage the flow.

Wall surface is approximately the same temperature as the air

Wrong. The heat can only be leaving via the walls and roof and floor.

Or by air infiltration and exfiltration. Oh look, Ron was wrong.

What if the thermostat is mounted on an internal partition? Is there's no temperature difference between the spaces and the air temperature is approximately equal to the wall temperature, there's nothing to generate convection.

Well would you look at that? Ron's wrong again.

What a ****.

Onetap wrote
Rod Speed wrote

The sensing element, the bi-metallic strip, responds
to the temperature of the bi-metallic strip.

Mindlessly silly.

A simple fact

Taint anything like a fact.

that you haven't managed to grasp.

Nothing to 'grasp'

The sensing element or transducer relies on heat transfer
to & from the medium to provide a temperature measurement.

Duh.

In this case we want to measure air temperature,

Duh.

the heat transfer to & from metal to air is mostly by convection

Wrong, as always.

and there is a heater inside the thermostat which will cause convection.

Not when the load off it doesnt.

Is that a co-incidence?

There is a reason the heater is off when the load is off, and you
still want the bi metallic strip to measure the temperature of the air.

Harry Bloomfield is right.

Are you Harry?

Nope.

Quite probably.

Even you should be able to check the headers, stupid.

Straw man? Who was the other troll who was fond of that phrase?

You wouldnt know what a real troll was if one bit you on your lard arse, boy.

I shall never care.

No one actually gives a flying red **** if you ever care.

Onetap wrote
Rod Speed wrote
Onetap wrote
Harry Bloomfield wrote

I cannot think of any circumstance where there would not be a flow
of air through a thermostat, without need of an internal heater to
encourage the flow.

Wall surface is approximately the same temperature as the air

Wrong. The heat can only be leaving via the walls and roof and floor.

Or by air infiltration and exfiltration.

That still happens via one of those, stupid.

Oh look, Ron was wrong.

Nope.

What if the thermostat is mounted on an internal partition?

That wall still has air moving up or down it.

Is there's no temperature difference between the spaces
and the air temperature is approximately equal to the wall
temperature, there's nothing to generate convection.

Try that again in english, when not ****ed.

Well would you look at that? Ron's wrong again.

Having fun thrashing that straw man ?

What a ****.

Wota stunning line in rational argument you have there.

On Wed, 07 Mar 2012 02:11:28 -0000, Rod Speed wrote:

Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote






Not if it hasnt got magnetised contacts to provide a snap action.

Presumably then it shouldn't have a rating for inductive load? I'm sure it did.

Presumably another one from china. All bets are off with the 'ratiings' with those.

I once bought a laptop power supply from there, and the mains lead conductors were hair-thin, much like the very fine
wire in the leads of Seinheiser (sp?) headphones. Also, within a few weeks, I managed to snap one of the prongs of
the plug, simply by pulling the plug out of the socket at a slight angle (not violently either).

And then there are those who had their pets killed by pet food from china.

And the chinese kids who died because some complete
arseholes were chucking melamine in the milk because
that increase the protien test results they were paid on.;

No that would never happen in the UK.......

You cant just use the amps with inductive loads.

Then why do they state them?

They are chinese.

I've seen some very good stiff from China, it's not all cheap ****e.

Oops.... STUFF....

Yeah, I buy most of the electronics I buy from there.

Not just electronics either. I bought some nail clippers for quite literally
1c, including postage which looked exactly like what I had lost.

They did turn out to be identical but the jaws didnt close properly,
didnt close squarely, so were useless. I told him that by email,
expected to be ignored because I had paid 1c but it didnt cost
anything to email him. He sent me another for free, and it was perfect.

I broke a pair of cheap snips (for wires), but I was cutting a piece of plastic - a bit on the side of a plastic backbox for some switch or other. The plastic was stronger than the steel (or whatever crappy metal it was) jaws, and one of the jaws snapped and pinged with considerable force across the room, after bouncing off my finger. I wondered what the **** had hit me!

I've bought lots of electronics that haven't turned up after a month, then they give me my money back, then it turns up another month later. How can "airmail" take 2 months? A plane simply couldn't fly that slowly, it's against the laws of physics!

Nope, not when the it turns on and the heater is off.

It doesnt do that when turning off either, when its turning
off, it isnt even using the air temp at all, the heater just
turns it off well before it would otherwise turn off to
significantly reduce the hysteresis.

THEN it measures the air temp again, with the resistor off.

Exactly.

Fraid not.

It's turning off when it shouldn't,

Nope, its turning off when it should to reduce the hysteresis.

therefore the heater is not on as long as it needs to be to keep
the room warm.

Wrong, it just comes on again sooner and keeps the room more
evenly warm than otherwise, because of the reduced hysteresis.

STILL no guessing of the temperature.

The resistor has to cool before it will allow the heater to come back on.

Sure but thats a minor part of the on/off ratio and you get a lower hysteresis anyway.

So it does what its designed to do very effectively indeed for peanuts.

You're always welcome to use a proper modern digital thermostat
for more money if you dont like the quirks inevitable with that design.

It wasn't very bloody effectively from what I've seen.

I am replacing them all with digitals. They shouldn't be making that ****e anymore.

It does bother me when its 4C colder than I prefer.

Why not set your room temperature so that you aren't near the minimum of your comfort zone?

There is no such thing. The temp I require varys with
what I am wearing and what I am doing etc etc etc.

Oh my god..... your life must be really complicated.

Nope.

Well I have to change my clothes twice a day only. When I get up and when I go to bed.

Can you program your stat to change temp depending on what clothing you're wearing?

I do it the other way, I wear what suits what its programmed to temp wise.

Well I have to change my clothes twice a day only. When I get up and when I go to bed!!

You could fit radio tags in everything....

Easier to wear what suits what its programmed to.

Well I have to change my clothes twice a day only. When I get up and when I go to bed!!!!

As I said most people have a zone of comfort, not one precise temperature.

If that was true, they wouldnt have been able to sell any of the bi
metallic strip thermostats for a higher price than the ones without heaters.

I reckon it's because people will pay more for something that says it's accurate.

I cant say I have ever seen a thermostat sold like that.

And few consumers buy thermostats anyway, they
usually come with the central heating they order.

"Oh that must be good, look it's got a 0.5C accuracy!"

Cant say I have ever seen a thermostat advertise an accuracy either.

It must be in the pamphlet. They always qquote temp range, accuracy, etc, etc. If one said "+/- 4C", people would think that doesn't sound very good.

Its just not possible, the accuracy you end up with depends on where its
located, how lossy the place being heated is, how responsive the heating
system is, whether you hold you mouth just right, whether you can monster
the kids into shutting the door when they tear in and out etc etc etc.

They still give a quote for lab conditions with some silly legal disclaimer.

Like people buy a car that can go 150mph when they never go over the speed limit.

I doubt too many buy the car based on the top speed it can do.

Yes they do. And brag about it. Then you ask how fast they've ACTUALLY driven.

I always insist on flooring it on a test drive - it's the best way to find the problems with it before you buy. And fun to scare the previous owner. My Golf can do 117 mph, and doesn't shake or rattle (apart from the passenger).

Yep, because its a lot more than a minute in total
for the whole trip when going out shopping etc.

But most of the time you are in a heated car or a heated shop.

And I prefer not to feel too cold when moving
between the car in the carpark and the shop etc.

For a minute!!! ONE MINUTE!!!!

Its more than one minute in the whole trip.

Not in one go. You really are a... what do they say in Australia? Jessie?

And I always take a top when flying, because they run the planes
too cold for my likely when wearing just a T shirt and shorts and
thongs/flip flops as I always do in spring/summer/autumn.

EGAD!

You can swoon now, we'll try not to laugh...

That's NOT what I was doing.....

Corse when we are having one of those 10 days over
40C the plane can get ****ING hot on the ground when
they turn it off for refueling with the passenger still on
board at the intermediate stops with the Saab 340Bs.

How much hand luggage do you take on board?

Normally nothing. I deliberately take one of the smaller paperback
that fit in a pocket.

But above you said about wearing all those different clothes because the plane is the wrong temperature!

I can just imagine you changing clothes 5 times during the flight.

You were warned about those magic mushrooms...

Well you do go on about needing the right clothing....

Your core temp doesn't change. You feel the cold when
your skin temp drops significantly unless you are like that
mate of mine that wears shorts right thru the entire winter.

Your skin temp is irrelevant.

Not to my comfort it aint.

Even if you are stupid enough to lie down naked in a snow drift,

Why is it stupid?

If you have to ask...

I do.

your core body temp wont be affected
but even you might feel a tad uncomfortable.

You'll be telling me you wash your hands in warm water next.

Fraid not, cold water suits me fine.

But.... aren't your hands all uncomfortable? You can't go outside for a minute without wearing a fur coat, yet your hands are fine in cold water.

I'm not into cold showers tho, even in the middle of those 10 days over 40C

I detest throwing away hot water straight down the drain.

Gotta love the way Aussies put "O" on the end of stuff!

Quite few burst a blood vessel when I talk about Japs.

Why?

We all call him Huge for a reason.

Aren't you meant to say the opposite?

Nope. We do with some, like bluey for a red haired person,
tho they are now called rangas. Short for orangutan.

Hahahha!!!!! I must remember that.

Thats what our current Prime Minister gets called, she's pom.

Do you guys still worship our Queen? If so can you please take the parasitical [expletive] away?

"Lofty" is normally the nickname of a short person for example.

I call kids midgets. That REALLY lights their fire.

I usually do, but some are taller than me!

Even he does wear a top when we are standing
around in the dark with a heavy frost at -10C for
an hour so outside with a decent wind.

The one who wears shorts right thru the winter doesnt show up that early.

I used to ride to school on a bike when I was a kid and in the
depths of winter, my ears felt like they might freeze off after the long downhill run. I wasnt stupid enough to do
that wearing just a T shirt and shorts.

That'll be why you're not used to it then. Kids these days are wrapped in cotton wool,

Try telling that that to my GP. His kid was showing
off to his mates riding his bike along the top of a
waist high wall at the school, fell off and broke is arm.

He should have done this: http://youtu.be/PBFHxBFQssk

He's too stupid for that.

He came very close indeed to a retrospective abortion

ROFL!

when on another occasion he was showing off to his mates how
much he knew about PCs by deleting files at random on his
dads PC that his dad used to keep all is patient records on.

Needless to say, no backups. That was in the days when
floppys were the only backup feasible even for a doctor.

I knew a professor who had THIRTY years work on an antique computer. He called me in a panic when it wouldn't start. When I asked when the last backup was done he drew a completely blank face and said "I'd never thought of doing that, should I have done?" He was bloody lucky I fixed it, I should have pretended it was ****ed though...

I did once walk along the balcony wall in the theatre at my school. The headmaster went NUTS!

Yeah, we've had a craze of 'planking' with stupid kids
doing that on balcony walls way up on multistory buildings.

A few have been winners of the Darwin award.

Life's no fun without risks, best to get your mates to do some of them though just in case.

Stop crying boy, you some sort of bald sook ?

That was not a cry, that was a "facepalm".

SURE it was. Pity about the sobbing that blows that claim completely out of the water.

http://lmgtfy.com/?q=facepalm

Fools no one. You cant hide the sobbing, boy.

Ignoranus.

The damned ancient greeks used to sit around in
their togas or whatever they wore and howl like that.

What?

You deaf ?

What are Greeks wearing togas to do with anything?

It wasnt what are wearing that matters, stupid.

Then explain your warped analogy.

We used to drive around in unheated cars in the
depth of winter and now arent that stupid anymore.

That change didnt actually produce the end
of civilisation as we know it for some reason.

It was unnecessary (apart from increasing driving visibility).

So are cars.

They perform a useful function, without them we would not be able to get form here to 200 miles away whenever we
want/need to.

So do thermostats, even you have one.

It's not THAT useful. I'd rather have no thermostat than no car.

We are getting more and more expensive ways of being comfortable,
and more and more things we won't have but are used to when they fail.

You're always free to go back to a cave if you want.

There is a sensible middle ground.

Yep proper modern digital thermostats.

Until something goes wrong. Millions of things are now relied upon or it's the end of the world.

Ever stopped to think how much money we spend on this comfort, and how much less work we'd have to do without it?

You're always free to smash ever thermostat you
own, and then take to the boiler with an axe etc.

Corse you might have to spend a night in the cells when the plods
show up with the funky canvas jacket with the extremely long sleeves.

Feel free to call me, I'm used to getting calls from the loony bin.

Think about the sentence I wrote again. Then come up with a sensible answer including numbers.

Time off is the ultimate comfort.

Depends on how much you like what you are doing.

You can make a case that by far the best arrangement is
when someone is actually stupid enough to pay you very
well indeed for doing what you would happily do for free.

Yes, although that isn't always possible.

Locally, no one did anything much special during the inevitable
10 days over 40C that happens many years. Now almost
everyone has at least an evaporative cooler, what the yanks
call a swamp cooler, and many have full airconditioning.

I can remember one car trip in conditions like that in a car
with no airconditioning at all. It was so ****ing hot that we
pulled up at a river and just jumped in the water and stayed
there in the shade in the water until the sun started to go down.

In those temps, wearing more clothes can be useful,

Nope. I built the house from scratch myself wearing just shorts, not even a T shirt.

with regular soakings of water. Lots of evaporation.

Doesnt work too well inside a car.

Open the windows when you drive along, much draught to allow the evaporation.

The seats go mouldy.

At that temperature, they dry off before mould can start.

Yes, whipping yourself furiously when naked can help
a bit in winter, but I prefer to wear more clothes myself.

There are other more interesting things to do when naked.

A likely story. I know about you poms.

http://youtu.be/BGf0QqvMBeU

And arent as comfortable as me.

I don't notice the temperature.

You would with one of our 10 days over 40C

Nonsense. I adapt.

Not even possible.

Of course it is, all animals adapt.

And you clearly don't, you heat your house.

I heat my garage for breeding parrots. I heat my house to prevent mould and busted pipes.

They're just as likely to buy a chrome plated one without a resistor.

Nope, because you cant buy them anymore.

Because no one is actually stupid enough to demand those.

I've seen plenty houses with chrome plated everything. I prefer brass myself.

You'd be dead if you tried digging ditches in ours.

I'd get used to it.

Not even possible. People die if they are that stupid.

Only if they are wimpy like yourself.

Cant be wimpy if I built my house in those conditions.

Now build one below zero.

As long as I was permitted to take my shirt off that is. And some drinks!

You'd still end up dead.

********.

Its happened. Plenty of you poms have ended up dead here that way.

There are wimpy poms too.

I'll be basking in the sun in my passive solar house pointing
at your frozen corpse in the snow drift and laughing.

Your house has been carted off by a glacier.

Not even possible here, too flat.

Something terrible would happen to it.

Nope.

Crushed by snow then.

Not even possible.

Read up on ice ages.

We don't get snow here.

Never missed skiing?

We do have much more skiable areas than you do, just not where I
personally live.

Mountains covered in snow? In Australia?

Yep. They might just be called the Snowy Mountains for a reason.

Bigger area than the whole of Britain in fact.

I wont call it a soggy little island again, otherwise
we will have more of that wimpy sobbing from you.

It ****ing well is soggy. And yet our water boards say we have to save water?!?

Yeah, likely, I meant to say that and forgot to say it.

How do you find the Golf ? My previous was a 72, lasted 35+ years until I was stupid enought to not bother to fix
the windscreen
leak that I kinew produced a wet floor when it rained much until
that eventually rusted a hole in the floor and was no longer
registerable and not economic to repair.

I have a hole in the floor too. I think it's from a leak in the sunroof.

It also has both locks busted, the radio-locking is broken, the
passenger window doesn't work, the bonnet catch is busted, and the rear washer is broken.

Sounds like the yanks are right, they've gone down hill a lot since mine.

It's no worse than any other car,

Its a hell of a lot worse than my Getz. Nothing has come off that
except the aerial I took off because I park it under the trees and
I was too lazy to trim the trees and it used to catch on that.

Who listens to the radio nowadays anyway?

I've come to the conclusion they are all pretty much the same now.

Fraid not.

Every make I've tried has fallen apart equally.

Ford, Renault, Peugeot, Rover, VW, Honda, .....

Like any other car there are little bits that go wrong that I don't bother fixing as they aren't really necessary.

That wasnt the case with mine over a much longer period than yours.

I don't tend to service or look after my cars.

Yeah, I dont either. The Golf only ever had one oil change in its entire life.

My Golf tells me when it needs new oil, so I do what it says. First car I've ever had that knows.

I've been told the engines last longer with fresh oil, but I dunno how much of that is bull****.

I did get the free one with the Getz but havent bothered with one since.

And it hasnt happened with the Hyundai Getz I replaced it with either.

Not one warranty quibble in the 5 year warranty. Even the Golf didnt manage that.

Or the beetle that I had before the Golf either.

I only replaced that with the Golf because I had a ****ing
great Alsatian that was absolutely obsessed with having
his head out the window, even in the depths of winter
and on long trips lasting days at highway speeds.

Define highway speed :-)

140KM/Hour in my case.

Pah! I drove 140 *mph* in a Renault Laguna. 140km/h is 86 mph! That's hardly even speeding!

Hilarious, you could watch him try to bite the semis going
past in the opposite direction in the driver's wing mirror.

He never actually managed to catch one.

That would have made a mess.

The beetle only has one opening window on each side and in
summer the bugger used to slobber down the back of my neck.

That's one reason I never got a dog. That and having to walk it.

I walk anyway.

And the ****.

I used to just mow it, can be quite spectacular when the dog lives
on dried dog food, quite a bit neveer gets digested and goes right thru.

URGH!!! Didn't that stink?

Dont bother to mow anymore, the jungle is only waist high, nothing to worry about.

The natural look?

The Golf fixed that, he got his own window and its got a heater
that allows him to have his way even in the depths of winter.

The heater is powerful enough to keep you at 30C while the window is open?

Didnt bother to measure, certainly warm enough so he was free to do what he wanted.

Corse he was such a massive great dog across the chest that there wasnt
actually a huge amount of open window even with it wound right down.

ROFL!

Thats another very common misapprehension. Its just
basic physics that you lose significantly less at the house
lower temps, because loss is entirely determined by the
temperature differential all other factors kept constant.

I know. But if it's 0C outside, and the house cools from 20C to 17C, then it still has a similar difference.

You still save by turning it off when you arent there.

Not by much at all. 20C minus 0C is pretty much equal to 17C minus 0C.

I dont buy the 17.

What?

And only a super insulated house will only drop
3C with it 0C outside if you are out all day.

It is well insulated. Double brick with foam insulation, double
galzing, and fibreglass in the attic with wooden flooring on top, and boxes full of stuff on top of that.

Sure, but thats not super insulated.

If it really was super insulated, you wouldnt need a boiler.

There is no such thing as completely insulated.

If you do have a super insulated house, you dont need a boiler.

It cools until it eventually approaches the outdoor temperature of 0C,

Not if its super insulated and there are people living in it.

But we were talking about when people are out.

at which point the pipes freeze and stuff goes damp and mouldy.

Nope, it need to get well below that for that to happen.

And if it really was super insulated, even just a 100W light bulb would ensure
that the pipes never froze even if you were away for the whole of the winter.

The mould happens earlier. Mind you it's damper here. 75% humidity is average.

--
http://petersparrots.com
http://petersphotos.com

Computers are like air conditioners: They stop working when you open Windows.

On Wed, 07 Mar 2012 02:37:59 -0000, brass monkey wrote:


"Rod Speed" wrote in message
...
Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote
Rod Speed wrote


large snip

And the award for patience in the line of ****ing stupidity goes to Rod
Speed. His responses are far beyond the call of duty and he deserves to be
heralded as a uk.d-i-y top-gun. Against all odds he selflessly attempted to
explain the operation of heated thermostats to a degree level scientist,
(without success). Apprenticeships just 'aint what they used to be.

I doubt you even have an O level you silly little troll.

--
http://petersparrots.com
http://petersphotos.com

INSTALLING SUMMER: ¦¦¦¦¦¦¦¦¦¦¦¦¦--------------- 44%
Installation failed.
404 error: Season not found.

"Lieutenant Scott" wrote in message
newsp.wasr2ha0ytk5n5@i7-940...
On Wed, 07 Mar 2012 02:37:59 -0000, brass monkey wrote:


"Rod Speed" wrote in message
...
Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote
Rod Speed wrote


large snip

And the award for patience in the line of ****ing stupidity goes to Rod
Speed. His responses are far beyond the call of duty and he deserves to be
heralded as a uk.d-i-y top-gun. Against all odds he selflessly attempted
to
explain the operation of heated thermostats to a degree level scientist,
(without success). Apprenticeships just 'aint what they used to be.

I doubt you even have an O level you silly little troll.

I only have a BEng, not a PhD like yourself but I don't tend to shout it
about too much. Then, when I type ******** I don't look so bloody stupid.

On Mar 4, 11:16*pm, Onetap wrote:
On Sunday, March 4, 2012 9:57:22 PM UTC, Harry Bloomfield wrote:
Wrong! There will always be a natural flow of air because they have
vents top and bottom. The resistor is simply there to reduce
hysteresis.

Why would there be a "natural flow of air" because there are air vents? I know there's ****ing air vents, but the presence of vents does not make the air move. *You need an energy input to move air (or anything else). You need a fan or a heat sourcesink that causes convection. Convection currents in the room will not necessarily cause air movement through the thermostat.

On Wed, 07 Mar 2012 12:24:46 -0000, brass monkey wrote:


"Lieutenant Scott" wrote in message
newsp.wasr2ha0ytk5n5@i7-940...
On Wed, 07 Mar 2012 02:37:59 -0000, brass monkey wrote:


"Rod Speed" wrote in message
...
Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote



large snip

And the award for patience in the line of ****ing stupidity goes to Rod
Speed. His responses are far beyond the call of duty and he deserves to be
heralded as a uk.d-i-y top-gun. Against all odds he selflessly attempted
to
explain the operation of heated thermostats to a degree level scientist,
(without success). Apprenticeships just 'aint what they used to be.

I doubt you even have an O level you silly little troll.

I only have a BEng, not a PhD like yourself but I don't tend to shout it
about too much. Then, when I type ******** I don't look so bloody stupid.

[admittance of talking ******** noted]

--
http://petersparrots.com
http://petersphotos.com

The only differences between lawyers and prostitutes are that prostitutes are generally better looking and more honest about how they make a living.

On Wednesday, March 7, 2012 2:00:52 PM UTC, Mathew Newton wrote:


* *Alternative view; the heater in the thermostat WILL generate convection air currents through the thermostat housing. Is this a coincidence?

Yes, it is.

Here's a link to what appears to be the original US patent, filed in
1926, on the use of an 'anticipator' within a thermostat...................

No, it isn't.

What is hysterisis, and how might you reduce it in a thermostat?

See the end of the post.

But first, a few of things you might not be aware of.

First, I suspect Harry is a bloke I had a disagreement with on another forum, he uses a similar vocabulary and rubbishes my posts at every opportunity. The topic was something to do with woodburners, I can't remember the exact details, can't be arsed to search, but it was something hair-raisingly stupid. He has since made a couple of other posts about innovations he has made (butchering a zone valve and a 3-port TMV control valve), both of which he was very proud and both of which were equally ****ing stupid.

Second, Harry seems to have a couple of accounts in different names on here. I suspect Rod Speed is Harry's sock puppet, Harry agreeing with Harry, but don't give a stuff. Rod uses a similar tactic, posting 'wrong' in response to anything I write.

Third, my background is mechanical building services. I stsrted in that field in about 1984 and have spent a fair bit of time on controls, mostly BMS. I did a bunch of BMS short courses and was the 'BMS bloke' on one site where there were 100 to 200 outstations (they were putting them in while I was there). Each outstation would have 3 or 4, or in some cases, 56 sensors, mostly thermistors, but also Rh, pressure, velocity, etc., sensors. I have had little involvement with thermostats (other than hard-wired manual-reset over-heat or frost protection stats) since all the control was done by PID loops in the BMS software in which the thermistor sensor provided the process variable. Thermostats were obsolete before I started.

Hysterisis, in this case, is where the rising room temperature reaches the set-point and the thermostat reacts some time later. Typically, this might involve a thermometer or sensor (or a black globe thermometer/ black bulb sensor) in the middle of a room, giving a very different reading to the stat or sensor on the wall. You can reduce the lag by increasing the air movement (15 AC/hr typical for close control), reducing the mass or heat capacity of the sensor element, or increasing the surface area (fins, heat sink) to increase the rate of heat transfer between sensor and air. Of these, lack of air movement has the most impact, since the air has a low density and small specific heat capacity. Adding a heater will increase the air flow through the thermostat housing and WILL reduce the hysterisis on a rising room temperature.

Rod/Harry has a high opinion of himself but has no grasp of what I regard as the fundamentals of heat transfer. I can guarantee that he has never heard of the mean radiant temperature and is, even now, Googling to find out what a globe thermometer is. The bloke's a ****.

On Wednesday, March 7, 2012 10:56:48 AM UTC, Rod Speed wrote:
Onetap wrote
Rod Speed wrote
Onetap wrote


Wall surface is approximately the same temperature as the air

Wrong. The heat can only be leaving via the walls and roof and floor.

Or by air infiltration and exfiltration.

That still happens via one of those, stupid.

Not necessarily, the conduits and ducts for electrical installations are also a source of air leakage. It gets interesting if the air leaks through the conduit which carries the sensor wiring, since outside air is then passing through the sensor wiring. I came across that on a job in which the temperature, humidity and room pressure were controlled. What was it you were pontificating about? Domestic wall thermostats How very quaint.

Oh, and if the heat loss by exfiltration was through any one of the building elements (walls, roof, floor) it wouldn't cool the surface and the surface wouldn't not generate convective air currents due to the heat loss. You're still wrong.

That wall still has air moving up or down it.

Is there's no temperature difference between the spaces
and the air temperature is approximately equal to the wall
temperature, there's nothing to generate convection.

Try that again in english, when not ****ed.


Perfect English, makes perfect sense to me. Do you need me to explain any of that in small words?

Well would you look at that? Ron's wrong again.

Having fun thrashing that straw man ?

What a ****.

Wota stunning line in rational argument you have there.

Argument? Didn't I tell you? I'm not arguing with you. The argument's over, you lost, You were disqualified for writing ********.

In message , Graham.
writes
On Mon, 5 Mar 2012 12:09:02 -0800 (PST), "js.b1"
wrote:

On Mar 5, 3:21*pm, Graham. wrote:
OK confession time.
For a long time I had the neutral terminal of my room stat connected
to the CPC because there was no neutral. The CU didn't contain an RCD
at the time

SI 2002 #2665, ESQCR.
"A consumer shall not combine the neutral and protective functions in
a single conductor in his consumer's installation."

Reason being whilst the earth tests as dead, when you disconnect the
CU earth then every single (electrically) earthed object in the house
including gas & water pipes re MEB is now a floating live whose
ability to shock is only limited by the resistor (in this case).


820k in this case, so less than 30mA if my maths are right.

Oh and just remembered I think the two indicator neons in the control
box were returned to earth for the same reason.


So the next time John Prescott comes around... :-)

'Twas a long time ago, I'll plead the statute of limitations.


I have the same problem - no neutral as the original thermostat was
simple on/off. However the new thermostat is double insulated and
doesn't need an earth, according to the manufacturer. The earth terminal
is there purely for convenience to park an earth wire, if it is present.
So provided I am sure this earth is isolated from all others and I put
blue tape on each end can I use it to feed a neutral to the new stat?
--
hugh

In message , Harry
Bloomfield writes
Rod Speed has brought this to us :
Onetap wrote
Graham. wrote

The other thing Onetap might consider is that the resistor body
is physically in contact with strip (at least it is on this old Satchwell
I have on the desk), so the design was to heat the strip
by conduction primarily.

So the resistor is in contact with the bi-mettalic strip. The
bi-metallic strip dissipates the heat to the air by convection
and to the surroundings by radiation. The convection causes
air currents to pass through the air vents. Anyone still having
difficulty with that one? I don't think it's that hard to grasp.

Different matter entirely to why the heater is there at all and why
bi metallic strip thermostats work fine if you disconnect the heater.

The ONLY effect you get when you do that is that the hystersis increases.

You do NOT get a set point shift.

The fact that the heater is only on when the load is has probably
got something to do with the high thermal capacity of the metal
and the high radiant emissivity of the metal surfaces.

Nope, nothing to do with that at all.

It actually allows the bi metallic strip to see what the temperature
of the air is.

Metal surfaces are usually colder than the air temperature,

Not even possible.

and usually are the first to attract condensation.

Thats wrong too.

Then again, I didn't design the things and have never used one.

Thats always been obvious.

Some control technicians thought the heater was effective for some
applications..

And its completely trivial to prove that the heater does reduce the
hysteresis as it was designed to do by whoever invented that approach.

They wouldnt add an extra cost item like that if it didnt do something;

You are wasting your time with providing explanations to this poster!

Maybe but it's been useful information for myself who has such a
thermostat but because of the way it is currently wired, the heater
doesn't work and so I will persevere with my attempts to get it wired up
correctly as I now am more convinced it will improve the performance of
my heating system.
--
hugh

On Mon, 05 Mar 2012 11:17:31 -0000, "Lieutenant Scott"
wrote:

I have a degree in Digital Microelectronics.

That explains a lot about the state of the UK today.

All that training and you appear to know nothing about control theory.
No idea about PID, no idea about the bi-metallic strip, no idea about
resistive heating, no idea about basic thermodynamics.

--

On Wed, 07 Mar 2012 23:12:51 -0000, The Other Mike wrote:

On Mon, 05 Mar 2012 11:17:31 -0000, "Lieutenant Scott"
wrote:

I have a degree in Digital Microelectronics.

That explains a lot about the state of the UK today.

All that training and you appear to know nothing about control theory.
No idea about PID, no idea about the bi-metallic strip, no idea about
resistive heating, no idea about basic thermodynamics.

DIGITAL.......

--
http://petersparrots.com
http://petersphotos.com

Lysdexia: a peech imspediment we live to learn with...

In message , The Other Mike
writes
On Mon, 05 Mar 2012 11:17:31 -0000, "Lieutenant Scott"
wrote:

I have a degree in Digital Microelectronics.

That explains a lot about the state of the UK today.

All that training and you appear to know nothing about control theory.
No idea about PID, no idea about the bi-metallic strip, no idea about
resistive heating, no idea about basic thermodynamics.

Mine is a Honeywell T6360 which doesn't have a bi-metallic strip.

"The thermostat sensing element comprises two circular,
flexible metal plates welded together at the rims
encapsulating a liquid whose pressure changes greatly in
response to small variations in temperature. In effect, this
dual diaphragm forms a 'bellows' which expands/contracts in
sympathy with the ambient temperature changes - this
movement serving to operate a snap acting switch rated to
control the heating or cooling circuit."

It doesn't show where the "anticipator" is physically located but the
wiring diagram shows it is only active when the thermostat is "on".
--
hugh

Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote
Rod Speed wrote
Lieutenant Scott wrote

I've seen some very good stiff from China, it's not all cheap ****e.

Oops.... STUFF....

Yeah, I buy most of the electronics I buy from there.

Not just electronics either. I bought some nail clippers for quite literally 1c, including postage which looked
exactly like what I had lost.

They did turn out to be identical but the jaws didnt close properly,
didnt close squarely, so were useless. I told him that by email,
expected to be ignored because I had paid 1c but it didnt cost
anything to email him. He sent me another for free, and it was
perfect.

I broke a pair of cheap snips (for wires), but I was cutting a piece
of plastic - a bit on the side of a plastic backbox for some switch
or other. The plastic was stronger than the steel (or whatever
crappy metal it was) jaws, and one of the jaws snapped and pinged
with considerable force across the room, after bouncing off my
finger. I wondered what the **** had hit me!

I've bought lots of electronics that haven't turned up after a month,
then they give me my money back, then it turns up another month
later. How can "airmail" take 2 months? A plane simply couldn't fly
that slowly, it's against the laws of physics!

Yeah, something odd with airmail from china.

At one time I would often get it in a couple of days, but lately it takes weeks.

And they mostly say it will take weeks on the ebay page too.

It does bother me when its 4C colder than I prefer.

Why not set your room temperature so that you aren't near the
minimum of your comfort zone?

There is no such thing. The temp I require varys with
what I am wearing and what I am doing etc etc etc.

Oh my god..... your life must be really complicated.

Nope.

Well I have to change my clothes twice a day only. When I get up and when I go to bed.

Thats all I normally do too.

Can you program your stat to change temp depending on what clothing you're wearing?

I do it the other way, I wear what suits what its programmed to temp wise.

Well I have to change my clothes twice a day only. When I get up and when I go to bed!!

Thats all I normally do too.

You could fit radio tags in everything....

Easier to wear what suits what its programmed to.

Well I have to change my clothes twice a day only. When I get up and when I go to bed!!!!

Thats all I normally do too.

Like people buy a car that can go 150mph when they never go over the speed limit.

I doubt too many buy the car based on the top speed it can do.

Yes they do. And brag about it.

Cant say I have ever had that, even with stupid kids.

Then you ask how fast they've ACTUALLY driven.

I always insist on flooring it on a test drive

I dont even bother with a test drive at all.

I bought the Getz after checking the basics online, ringing
the Hyundai dealers in my state capital, rubbing the local
dealer's nose in the best price I could find, had him claim
that he has to pay a higher delivery charge than they do,
agreed to pay the higher delivery charge, and told him
to ring me when the car was ready to pick up.

The dealer principle was quite literally speachless when
I told him that I hadnt even bothered with a test drive,
and II put it on my card too, paying cash for a new car.

- it's the best way to find the problems with it before you buy.

Dont have that problem with a new car and since I used the
last one for 35+ years and couldnt keep using it due to my
stupidity, there isnt any point in farting around with used cars.

And fun to scare the previous owner. My Golf can do 117 mph, and doesn't shake or rattle (apart from the passenger).

I did have a test drive with the Golf. The dealer principle
did a pretty interesting demo, put one wheel in the dirt,
the other one on the sealed road, at highway speed,
jammed his foot on the brake as hard as he could and
didnt have any hands on the wheel. Pretty impressive.

The beetle only has one opening window on each side and in
summer the bugger used to slobber down the back of my neck.

That's one reason I never got a dog. That and having to walk it.

I walk anyway.

And the ****.

I used to just mow it, can be quite spectacular when the dog lives
on dried dog food, quite a bit neveer gets digested and goes right thru.

URGH!!! Didn't that stink?

Nar, with 10 days over 40C and 5% humidity it
damned near dries out before it hits the ground.

Dont bother to mow anymore, the jungle is only waist high, nothing to worry about.

The natural look?

Yep, bugger the neighbours.

Corse it was a bit of a problem when I wanted to grow vegys.

Kikuyu is basically african jungle pretending to be grass.

The Golf fixed that, he got his own window and its got a heater
that allows him to have his way even in the depths of winter.

The heater is powerful enough to keep you at 30C while the window is open?

Didnt bother to measure, certainly warm enough so he was free to do what he wanted.

Corse he was such a massive great dog across the chest that there wasnt actually a huge amount of open window even
with it wound right down.

ROFL!

Thats another very common misapprehension. Its just
basic physics that you lose significantly less at the house
lower temps, because loss is entirely determined by the
temperature differential all other factors kept constant.

I know. But if it's 0C outside, and the house cools from 20C to 17C, then it still has a similar difference.

You still save by turning it off when you arent there.

Not by much at all. 20C minus 0C is pretty much equal to 17C minus 0C.

I dont buy the 17.

What?

You deaf ?

And only a super insulated house will only drop
3C with it 0C outside if you are out all day.

It is well insulated. Double brick with foam insulation, double
galzing, and fibreglass in the attic with wooden flooring on top,
and boxes full of stuff on top of that.

Sure, but thats not super insulated.

If it really was super insulated, you wouldnt need a boiler.

There is no such thing as completely insulated.

I said super insulated, not completely insulated.

And cool rooms are completely insulated anyway.

If you do have a super insulated house, you dont need a boiler.

It cools until it eventually approaches the outdoor temperature of 0C,

Not if its super insulated and there are people living in it.

But we were talking about when people are out.

Then even a 100W bulb will do fine.

On Wed, 07 Mar 2012 23:19:00 -0000, "Lieutenant Scott"
wrote:

On Wed, 07 Mar 2012 23:12:51 -0000, The Other Mike wrote:

On Mon, 05 Mar 2012 11:17:31 -0000, "Lieutenant Scott"
wrote:

I have a degree in Digital Microelectronics.

That explains a lot about the state of the UK today.

All that training and you appear to know nothing about control theory.
No idea about PID, no idea about the bi-metallic strip, no idea about
resistive heating, no idea about basic thermodynamics.

DIGITAL.......


FFS what DID they teach you?

What esteemed institution did you get this degree from?


--

On Thu, 08 Mar 2012 00:17:11 -0000, The Other Mike wrote:

On Wed, 07 Mar 2012 23:19:00 -0000, "Lieutenant Scott"
wrote:

On Wed, 07 Mar 2012 23:12:51 -0000, The Other Mike wrote:

On Mon, 05 Mar 2012 11:17:31 -0000, "Lieutenant Scott"
wrote:

I have a degree in Digital Microelectronics.

That explains a lot about the state of the UK today.

All that training and you appear to know nothing about control theory.
No idea about PID, no idea about the bi-metallic strip, no idea about
resistive heating, no idea about basic thermodynamics.

DIGITAL.......


FFS what DID they teach you?

What esteemed institution did you get this degree from?

Do you want me to photograph the ****ing certificate?

--
http://petersparrots.com
http://petersphotos.com

Tower: "Delta 351, you have traffic at 10 o'clock, 6 miles!"
Delta 351: "Give us another hint! We have digital watches!"

"Lieutenant Scott" wrote in message
newsp.watshf07ytk5n5@i7-940...
On Thu, 08 Mar 2012 00:17:11 -0000, The Other Mike
wrote:

On Wed, 07 Mar 2012 23:19:00 -0000, "Lieutenant Scott"
wrote:

On Wed, 07 Mar 2012 23:12:51 -0000, The Other Mike
wrote:

On Mon, 05 Mar 2012 11:17:31 -0000, "Lieutenant Scott"
wrote:

I have a degree in Digital Microelectronics.

That explains a lot about the state of the UK today.

All that training and you appear to know nothing about control theory.
No idea about PID, no idea about the bi-metallic strip, no idea about
resistive heating, no idea about basic thermodynamics.

DIGITAL.......


FFS what DID they teach you?

What esteemed institution did you get this degree from?

Do you want me to photograph the ****ing certificate?

No need for that, but if I were you I'd take bloody good care of it.
Safety deposit box perhaps.
LMFAO.

hugh ] wrote:

I have the same problem - no neutral as the original thermostat was
simple on/off. However the new thermostat is double insulated and
doesn't need an earth, according to the manufacturer. The earth terminal
is there purely for convenience to park an earth wire, if it is present.
So provided I am sure this earth is isolated from all others and I put
blue tape on each end can I use it to feed a neutral to the new stat?

No.
What if the cable is cut half way along in the future? Blue and
Brown/Red and black will both be live, and copper will be neutral.
Also, no insulation on the ends. Far too easy to get it wrong in the
future when you have gone.
Someone drills through the cable - it wont trip as there is no earth
there, so they'll be buzzing away, using your electric to fry, and
hopefully pass enough current through themselves to trip the fuse/CB
through an overload.

But people do things like this all the time, as it is your house, do
whatever you want.

Alan.

--
To reply by e-mail, change the ' + ' to 'plus'.

On Mar 7, 8:09*pm, Onetap wrote:

Here's a link to what appears to be the original US patent, filed in
1926, on the use of an 'anticipator' within a thermostat...................

http://www.google.com/patents/US1583496

* No, it isn't.

Err, yes it is.

What do you think it is?

Mathew

On Mar 7, 10:17*pm, hugh ] wrote:

I have the same problem - no neutral as the original thermostat was
simple on/off. However the new thermostat is double insulated and
doesn't need an earth, according to the manufacturer. The earth terminal
is there purely for convenience to park an earth wire, if it is present.
So provided I am sure this earth is isolated from all others and I put
blue tape on each end can I use it to feed a neutral to the new stat?

It would contravene the wiring regs, in particular BS 7671 514.4.2
which states that a green/yellow cable is not to be used for any
purpose other than as a protective conductor (at may not be overmarked
to the contrary at the terminations).

Mathew