Personal opinion, and counter to what most responses to this will
be, but:

If I'm answering an easy question, I top post because the OP
knows what he's already asked and he's prime. IF others have
been following the thread, they also know what's been said or,
sometimes might have to dip down to see the original question,
but it's no big deal for me, shouldn't be for them.

If it's more comples, I post inline and trim contectually.

If it's an ongoing discussion I bottom post because it's easiest
to go back thru a long post to read it chronologically.

Most of the silly where-post talk, including my own message here,
is just to waste time when it's available and to quiver a liver
here and there for those who make too much out of it.

That said,

"Guy King" wrote in message
...
The message Zz3Qf.6150$sp4.4886@trnddc01
from "Gooey TARBALLS" contains these
words:

I'm new to these groups. And I think I "top post."

Thing is - I've no idea to what you're referring unless I first
read the
bottom of the page - which is counter to how most people read
English.

eg.

Because it goes counter to the flow of how English is read.

Why is top-posting bad?

--
Skipweasel
Pay no attention to the man behind the curtain.

sometimes I do both. g.

Pop

On Fri, 10 Mar 2006 13:00:40 GMT someone who may be Guy King
wrote this:-

The trouble is they draw water from hot /and/ cold when hot is required
- for two reasons. 1) There may be no hot water connected 2) The hot
water may be too hot.

This could easily be solved with more complicated controls, which
would measure water temperatures. They would then use as much hot
water as possible, only adding cold if the hot was too hot for the
programme selected. No doubt manufacturers think this would cost too
much.

Equalising the pressure on the hot and cold sides, by feeding them
from the same source, can also reduce the enthusiasm of the cold
water.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Doctor Drivel wrote:

... a collector above an unpressurized tank with the ends of the supply
and return pipes underwater and a small hole above the water line. This
would need less pumping energy than a system with the return pipe above
the water line.

The air hole in the pipe needs to be exposed when the pump is operating...
If the water level is too high then no drain down.

simpler to have the vent hole above the top of the tank. Add a sleeve
to prevent splash possibility.

It has to be "in" the tank. The pump will squirt water everywhere. Best to
have say 15mm into the tank, then immediately up to 28mm (1")...

Or put a T 6' above the tank with a small tube that goes back to the tank.

Nick

"David Hansen" wrote in message
...
On Fri, 10 Mar 2006 13:00:40 GMT someone who may be Guy King
wrote this:-

The trouble is they draw water from hot /and/ cold when hot is required
- for two reasons. 1) There may be no hot water connected 2) The hot
water may be too hot.

This could easily be solved with more complicated controls, which
would measure water temperatures. They would then use as much hot
water as possible, only adding cold if the hot was too hot for the
programme selected. No doubt manufacturers think this would cost too
much.

Equalising the pressure on the hot and cold sides, by feeding them
from the same source, can also reduce the enthusiasm of the cold
water.

A neighbour saw that on a 50C wash hot an cold came in and mixed making the
50C tap water about 30C, then the electric element cut in to heat the water
to 50C. She realised that at the very hot wash (90C?) only hot ever came
through and the cold was off. So she made sure hot water was at the tap,
selected the 90C wash and the drum filled with 50C water, then she would
switch off and then select the 50C wash. It worked, also the wash was
quicker.

wrote in message
...
Doctor Drivel wrote:

... a collector above an unpressurized tank with the ends of the
supply
and return pipes underwater and a small hole above the water line.
This
would need less pumping energy than a system with the return pipe
above
the water line.

The air hole in the pipe needs to be exposed when the pump is
operating...
If the water level is too high then no drain down.

simpler to have the vent hole above the top of the tank. Add a sleeve
to prevent splash possibility.

It has to be "in" the tank. The pump will squirt water everywhere. Best to
have say 15mm into the tank, then immediately up to 28mm (1")...

Or put a T 6' above the tank with a small
tube that goes back to the tank.

6 foot? This pipe will take water back to the tank, and may disturb
stratification. You could have it horizontal above the tank water line and
it sprays onto the surface not disturbing stratification. Best have the pipe
small bore like 6mm to 8mm.

As hot water comes in from the panels you want this to stay at the top of
the tank. You don't want to disturb any stratification aiming to reinforce
it putting hot water at the top. Pumping it into the centre of the water
body will make it warm with mixing. Not what you want.

Best have a tee under the lowest water level that acts as a spreader. Pipe
in - tee - two lengths of pipe horizontal from each port of the tee to
the edges of the tank - cap on each end. Drill holes in speader pipe
horizontally, so hot water does not flow downwards into the main water body
and stays on the surface.

Now for the vent. Just before the speader tee insert another tee, this can
be under the water line. Take a soft copper pipe, about 8mm, from the tee up
and out of the water to the highest level in the tank, Bend it downwards in
a "U". Depending on pump pressure and size of holes in the spreader pipes,
water should take the line of least restisance and not work its way up the
soft copper pipe, only exiting via the speader pipes.

But if enough people go to Rome, and do different, what people do in
Rome changes..

PopS wrote:
...
Now you bottom feeders may be using some other mail reader. And
maybe you can recommend one better suited to the task than
Outlook. But, as I said, from this perspective it seems
everyone should change and do it (respond) my way.

See, that's where nearly everyone's wrong. No one should change.
They should simply do what makes sense and allow for a variation
of opinions. If one cannot do as t hey do in rome, don't go to
rome ...

Pop


So there.

"David Hansen" wrote in message
...
On Fri, 10 Mar 2006 09:54:57 +0000 someone who may be AJH
wrote this:-



However, for solar water heating the disadvantages of an open vented
system include the trouble of placing the header tank high enough,
then maintaining it and the inability to heat water above 100C.

?



The system at http://www.solartwin.com/easy_to_plumb_in.htm involves
much less plumbing, so is easy to fit and has simple PV powered
controls. Provided that the existing hot water cylinder is well
insulated and of an adequate size this has great advantages.

That's the one we have, with which we are so well pleased.

You'll also note at the bottom of the page, "Solartwin offers minimum
disruption when installing, and then is as equally easy to un-install and
load in a van when moving house.

It'sguaranteed for up to (I think) three moves. So no potential buyer of the
house need be put off and the happy owner won't be deprived. :-)
Mary

"Guy King" wrote in message
...
The message ews.net
from "Doctor Drivel" contains these words:

PS maybe 'mericans arent familiar with the fact that British washing
machines dont use a hot water feed.

Some do. Mine does and it is pretty new.

Mine certainly does.

So does ours. It's not new.

Mary

"Doctor Drivel" wrote in message
reenews.net...

A neighbour saw that on a 50C wash hot an cold came in and mixed making
the 50C tap water about 30C, then the electric element cut in to heat the
water to 50C. She realised that at the very hot wash (90C?) only hot ever
came through and the cold was off. So she made sure hot water was at the
tap, selected the 90C wash and the drum filled with 50C water, then she
would switch off and then select the 50C wash. It worked, also the wash
was quicker.


You should explain to her that you don't need 50C for a wash.
Set it to 40C or even 30C and save some energy.

On Fri, 10 Mar 2006 15:35:59 -0000 someone who may be "Mary Fisher"
wrote this:-

However, for solar water heating the disadvantages of an open vented
system include the trouble of placing the header tank high enough,
then maintaining it and the inability to heat water above 100C.

?

Provided it is under enough pressure water can be heated to above
100C. It will not turn into steam, unless the pressure is reduced.
Such systems are used in big heating systems.

However, this is very much something for those who know what they
are doing. It is best to think of such high temperature hot water
systems as liquid steam, because if it gets out the results are very
nasty. My staff once had to recover the bodies of two men who had
been killed by such a system and it haunted them.

The application to solar heaters is more complicated than I wanted
to explain, but I will now. In any heating system one wants an
adequate margin between what happens normally and what might happen
in a strange situation. If an open vented solar water heating system
was running with the water coming out of the collector at 95C then
there is little margin between hot water coming out and the hot
water turning into steam. There is little pressure because the
header tank is likely to only just be above a roof mounted collector
and thus the water will turn into steam at 100C. This isn't so much
of a problem with flat plate collectors, which are unlikely to reach
this temperature, but it will be with evacuated tube collectors.

With a pressurised system there is more margin, so that in odd
conditions the collector could get to say 120C without too much risk
of a problem. This could happen if the pump is not working for some
reason, such as a power cut. With the Solartwin and Imagination
systems the collector will never get to this sort of temperature
anyway and the pump is solar powered and thus fewer things can go
wrong with its electricity supply.

You'll also note at the bottom of the page, "Solartwin offers minimum
disruption when installing, and then is as equally easy to un-install and
load in a van when moving house.

That is one of the advantages of the system. I think that if they
could reduce the price of the unit they could corner a large slice
of the market. When they started selling it some years ago ISTR a
price of £1500, rather then the current £2000. However, reducing the
price means increasing the volume sold and that depends on reducing
the price...


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Mary Fisher wrote:
"David Hansen" wrote in message
...

The system at http://www.solartwin.com/easy_to_plumb_in.htm involves
much less plumbing, so is easy to fit and has simple PV powered
controls. Provided that the existing hot water cylinder is well
insulated and of an adequate size this has great advantages.

That's the one we have, with which we are so well pleased.

Does seem nice and simple but £2000 for the DIY kit buys a lot of gas heated
hot water. Certainly our house would be very suitable for solar water
heating (rear of house faces due south, v. little shade).

Tim

Doctor Drivel wrote:
wrote in message

simpler to have the vent hole above the top of the tank. Add a sleeve
to prevent splash possibility.

It has to be "in" the tank. The pump will squirt water everywhere.

What I'm suggesting is a 1/4" hole in the panel output pipe just above
the top of tank, say 1/2" above. There will be close to no pressure
there, and no possibility of any squirting.

NT

On Fri, 10 Mar 2006 17:02:26 -0000 someone who may be "Tim Downie"
wrote this:-

Does seem nice and simple but £2000 for the DIY kit buys a lot of gas heated
hot water. Certainly our house would be very suitable for solar water
heating (rear of house faces due south, v. little shade).

If the price of gas were to remain the same the simple payback
period would be around 20-25 years. However, unlike the price of
sunshine, the price of gas is unlikely to remain the same.

There are also other reasons for installing such things, for example
reducing greenhouse gas emissions and reducing the maintenance
on/extending the life of the boiler (which can usually be turned off
for several months a year).


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

AJH wrote:
On 9 Mar 2006 14:05:11 -0500, wrote:
Derek Broughton wrote:

"Those guys" show a system that is reliable as long as that valve opens.

Aha. I've been thinking drainBACK, as in "the water drains back when the pump
stops, by gravity, with no valve."

Yes this was my assumption, the water header being sufficient cross
section, and within the insulated area of the house, that once the
pump stopped it just filled up a bit. The only drawback I could see
was that the pump would always work against the head from the header
tank up to the panels. In a sealed system the pump only circulates
against the friction in the system.

I realised this isnt so. Once the panel circuit fills with water, the
pump is only pumping against the running friction, and not the head.
The panel output piping is filled with water after a second or 2, so
gravity has the same effect on both sides, so no extra pumping
resistance.

NT

David Hansen wrote:
On Fri, 10 Mar 2006 09:54:57 +0000 someone who may be AJH
wrote this:-

Once the option for sealed
system is taken I can see little advantage in drainback over a glycol
or food grade antifreeze system.

When you choose sealed you're choosing not drainback, so the above
doesnt seem to make sense, unless you know of a sealed drainback
design?


However, for solar water heating the disadvantages of an open vented
system include the trouble of placing the header tank high enough,

I cant see how this is a problem. The loft is normally fine, sitting on
the usual dividing wall. The tank is below the panels for drainbacks,
it only needs to be above them for thermosyphons, which are not the
usual choice.

then maintaining it

again I dont see any downside with vented system maintenance. Sealed
system maintenance does introduce extra issues, and for CH seems to
result in more maintenance need in practice, as well as being less easy
to work on.

and the inability to heat water above 100C.

That is one of the plusses for vented systems, that they will never go
into that dangerous region of pressurised steam. Any sealed system that
does requires extra certification, which isnt free, and must be
designed to withstand much higher pressures. If it is not pressure safe
then its just dangerous. Vented eliminates any such risk. Worst case
for vented is steam coming out the overflow pipe, a non issue, or in
the highly unlikely event of both a system boiling and a blocked
overflow pipe, the steam simply comes out from around the tank lid.
Safely.


The system at http://www.imaginationsolar.com/system.htm has a
number of advantages. One of these is that it does not use mains
electricity, which can exterminate 20% of the savings gained by
using solar hot water heating [1]. The control system is very
simple, if the sun is shining it pumps water into the panel and
starts warming up the cylinder. If the sun is not shining, or there
is snow on the PV panel, then the pump is not running and the panel
is drained of water.

Imho this is more the hype than the reality. The one advantage of a
solar panel pump supply is simplicity, but thats all. The electricity
created by the solar panel is the opposite of a worthwhile investment
for 99% of end users. The control system is a bit crude, and will
result in the system actively cooling your HW some of the time instead
of heating it. In short it isnt worth it, unless you're just not
skilled to do anything better.


NT

David Hansen wrote:

...There is little pressure because the header tank is likely to only just
be above a roof mounted collector and thus the water will turn into steam
at 100C. This isn't so much of a problem with flat plate collectors, which
are unlikely to reach this temperature, but it will be with evacuated tube
collectors.

Not if the pump turns off and the water drains down at 95C. For long life,
EPDM-lined tanks should be less than 77C.

Nick

PS maybe 'mericans arent familiar with the fact that British washing
machines dont use a hot water feed.

Solar Flare wrote:
So it used to be the "White and blue"? and now it is the "grey and the
blue"?

Ah yes, ignorance. Our machines use cold fill because by the time the
hot gets thru the pipes the machines have already had enough water. The
water is heated electrically within the machine.

Cue silly statement about enormous pipes...


NT

dennis@home wrote:
wrote in message

PS maybe 'mericans arent familiar with the fact that British washing
machines dont use a hot water feed.

Most of them do.
There aren't many cold feed only machines in Currys.

Pedant mode: they dont use the hot fill for most washes, only for the
boiling washes will they use it.


NT

Doctor Drivel wrote:

In yea olden dayes the dishwasher
was a large tray of water with powder like sand. It sand blasted the dishes
clean, hence why you could not put patterned plates in the things.

Early dw machines can be seen on various net sites, and in books from
the time. They used flow of hot water and soap to clean the dishes, and
were only really effective on freshly used still wet food. They were
used in large kitchens, being ineffective for smaller scale use.
Restaurant machines are descended from these, todays home machines use
somewhat different principles. The simplest early dishwashers were no
more than a sink of hot soapy water with a pump to circulate it, plus a
clean rinsing sink.

If you have any reference or link to sandblasting dishwashers I'd be
curious to see it, but I'm doubtful.


NT

"dennis@home" wrote in message
. uk...

"Doctor Drivel" wrote in message
reenews.net...

A neighbour saw that on a 50C wash hot an cold came in and mixed making
the 50C tap water about 30C, then the electric element cut in to heat the
water to 50C. She realised that at the very hot wash (90C?) only hot
ever came through and the cold was off. So she made sure hot water was
at the tap, selected the 90C wash and the drum filled with 50C water,
then she would switch off and then select the 50C wash. It worked, also
the wash was quicker.


You should explain to her that you don't need 50C for a wash.
Set it to 40C or even 30C and save some energy.

Whites still need hot washes, no matter what they say.

wrote in message
oups.com...
AJH wrote:
On 9 Mar 2006 14:05:11 -0500, wrote:
Derek Broughton wrote:

"Those guys" show a system that
is reliable as long as that valve opens.
Aha. I've been thinking drainBACK,
as in "the water drains back when
the pump stops, by gravity, with no valve."

Yes this was my assumption, the water header being sufficient cross
section, and within the insulated area of the house, that once the
pump stopped it just filled up a bit. The only drawback I could see
was that the pump would always work against the head from the header
tank up to the panels. In a sealed system the pump only circulates
against the friction in the system.

I realised this isnt so. Once the
panel circuit fills with water, the
pump is only pumping against the
running friction, and not the head.

It is pumping against the head (pressure) always. Gravity asserts pressure.
A 3 floor British house with attic. Inc' space between floor it could be 10
foot per floor. A radiator in the attic space and the pump at the bottom of
the ground floor. The pump has to overcome 1 bar (~30 foot), one atmosphere,
to get to the top, even in a sealed system. OK is assisted a little when
the water is dropping from 30 foot on the return, but it still has to
overcome one atmosphere plus system friction. Gravity doesn't care if it is
open vented or sealed.

wrote in message
oups.com...
dennis@home wrote:
wrote in message

PS maybe 'mericans arent familiar with the fact that British washing
machines dont use a hot water feed.

Most of them do.
There aren't many cold feed only machines in Currys.

Pedant mode: they dont use the hot fill for most washes, only for the
boiling washes will they use it.

Hotpoints use hot for washes other than boil.

wrote in message
ups.com...
David Hansen wrote:
On Fri, 10 Mar 2006 09:54:57 +0000 someone who may be AJH
wrote this:-

Once the option for sealed
system is taken I can see little advantage in drainback over a glycol
or food grade antifreeze system.

When you choose sealed you're choosing not drainback, so the above
doesnt seem to make sense, unless you know of a sealed drainback
design?

Sealed and pressurised are two differnt things. You can have a sealed
system with an air gap in the top of a cyldiner, yet it is not pressurised -
only when heated. When cold it will be atmospheric.

However, for solar water heating the
disadvantages of an open vented
system include the trouble of placing
the header tank high enough,

I cant see how this is a problem.

It isn't a problem an open vented drainback system does not requires a
header tank at all, just space in a tank or cylinder at a lower level for
the panels to drain into.

The system at http://www.imaginationsolar.com/system.htm has a
number of advantages. One of these is that it does not use mains
electricity, which can exterminate 20% of the savings gained by
using solar hot water heating [1]. The control system is very
simple, if the sun is shining it pumps water into the panel and
starts warming up the cylinder. If the sun is not shining, or there
is snow on the PV panel, then the pump is not running and the panel
is drained of water.

Imho this is more the hype than the reality. The one advantage of a
solar panel pump supply is simplicity, but thats all. The electricity
created by the solar panel is the opposite of a worthwhile investment
for 99% of end users. The control system is a bit crude, and will
result in the system actively cooling your HW some of the time instead
of heating it. In short it isnt worth it, unless you're just not
skilled to do anything better.

It is true a solar powered pumps may reverse the panel/cylinder and
dissipate heat. But it is its overall performance that matters over a year.

wrote in message
oups.com...
dennis@home wrote:
wrote in message

PS maybe 'mericans arent familiar with the fact that British washing
machines dont use a hot water feed.

Most of them do.
There aren't many cold feed only machines in Currys.

Pedant mode: they dont use the hot fill for most washes, only for the
boiling washes will they use it.

Most will on 50C and above.

wrote in message
ups.com...
Doctor Drivel wrote:

In yea olden dayes the dishwasher
was a large tray of water with powder like sand. It sand blasted the
dishes
clean, hence why you could not put patterned plates in the things.

Early dw machines can be seen on various net sites, and in books from
the time. They used flow of hot water and soap to clean the dishes, and
were only really effective on freshly used still wet food. They were
used in large kitchens, being ineffective for smaller scale use.
Restaurant machines are descended from these, todays home machines use
somewhat different principles. The simplest early dishwashers were no
more than a sink of hot soapy water with a pump to circulate it, plus a
clean rinsing sink.

If you have any reference or link to sandblasting dishwashers I'd be
curious to see it, but I'm doubtful.

Did you ever feel that powder? My first dishwasher would clean the chrome
over grills and shelves spotless, as it sand blasted them. The powder was
course and took a long time to dissolve. The new one does not. But the
crockery is much cleaner.

Yes, well said. Let's cater to those active folks following the threads.


"PopS" wrote in message
news:5NfQf.10505$452.5346@trndny03...
Personal opinion, and counter to what most responses to this will be, but:

If I'm answering an easy question, I top post because the OP knows what
he's already asked and he's prime. IF others have been following the
thread, they also know what's been said or, sometimes might have to dip
down to see the original question, but it's no big deal for me, shouldn't
be for them.

If it's more comples, I post inline and trim contectually.

If it's an ongoing discussion I bottom post because it's easiest to go
back thru a long post to read it chronologically.

Most of the silly where-post talk, including my own message here, is just
to waste time when it's available and to quiver a liver here and there for
those who make too much out of it.

That said,

"Guy King" wrote in message
...
The message Zz3Qf.6150$sp4.4886@trnddc01
from "Gooey TARBALLS" contains these words:

I'm new to these groups. And I think I "top post."

Thing is - I've no idea to what you're referring unless I first read the
bottom of the page - which is counter to how most people read English.

eg.

Because it goes counter to the flow of how English is read.

Why is top-posting bad?

--
Skipweasel
Pay no attention to the man behind the curtain.

sometimes I do both. g.

Pop

"dennis@home" wrote in message
. uk...

wrote in message
oups.com...
dennis@home wrote:
wrote in message

PS maybe 'mericans arent familiar with the fact that British washing
machines dont use a hot water feed.

Most of them do.
There aren't many cold feed only machines in Currys.

Pedant mode: they dont use the hot fill for most washes, only for the
boiling washes will they use it.

Hotpoints use hot for washes other than boil.

60% of washing machines sold in the UK are Hotpoints. I don't know why as
they are complete crap. They also hold the market for fridges, which they
are better at.

"Gooey TARBALLS" wrote in message
news:YQkQf.3744$wH5.3216@trnddc02...
Yes, well said. Let's cater to those active folks following the threads.

Top poster

** PLONK **

On Fri, 10 Mar 2006 10:24:49 GMT, "dennis@home"
wrote:


Dishwashers are almost invariably cold fill.

Mine takes water up to 60ºC, so I'd expect some can.

Depends largely on the run length of the hot pipe to the dishwasher,
but as the short prewash and first rinse don't have to be so hot, the
initial cooler water from the pipes may not be such a problem.

cheers,
Pete.

wrote in message
oups.com...
Doctor Drivel wrote:
wrote in message

simpler to have the vent hole above the top of the tank. Add a sleeve
to prevent splash possibility.

It has to be "in" the tank. The pump will squirt water everywhere.

What I'm suggesting is a 1/4" hole in the panel output pipe just above
the top of tank, say 1/2" above. There will be close to no pressure
there, and no possibility of any squirting.


Okay, and if there is no check-valve in the pump or its suction, I can see
that working. Maybe even a baffle just to be sure of little splash.
Shut-off head of the pump will still have to be high enough to initially
fill the collector, but once the return has flooded, less pressure should be
needed to maintain flow.

Now, just need a large enough tank to accomodate the drain-water, and you're
all set.

daestrom

"Guy King" wrote in message
...
The message .com
from contains these words:

Lots of people round the country expose hosepipes to subzero temps day
in day out. Does this make them burst? No, because theyre not full of
water.

Even those that are don't burst 'cos they're sufficiently elastic.


If by 'hosepipes' you mean the 'outside faucet' used to water the
garden/etc..., around here we use 'frost-free' faucets. The valve stem is
quite long (about 12 inches) and the actual valve/seat located inside the
house. As long as the hose is disconnected so the foot long section from
actual valve to the faucet can drain, these don't have a problem even in 0F
winter nights like we have here in NY. Because none of the flooded portion
upstream of the actual valve seat is exposed to freezing conditions.

daestrom

"raden" wrote in message
...
In message , daestrom
writes

"raden" wrote in message
...
In message , "David Turner,
Island Computers US Corp" writes
Calculated using 13C/KW not 9c for a start

Remember this new thing call ed fuel recovery charge - well we get
stuffed
with it and it is going up again this month

Our KW cost 2 years ago was one of the lowest in the US at 7c/KW

Figure it out

Granted I have a high electric bill from other things but HOT water is
defintely the highest cost


The computer illiterate wannabe septic's done it again

no context because what he was replying to follows his sig sep

here ...



Actually, the entire previous message is contained below. Must be your
screwed up settings. The server shows his (David's) message, followed by
'Docter Drivel's message. You saying your news-reader is worse than
OhOh-Express???

It's there because I copied and pasted it you simpleton. Note the "what he
was replying to follows his sig sep


Nope. It was there in his reply (before you got to it). Must be your
news-reader.

daestrom

"Pete C" wrote in message
...
On Fri, 10 Mar 2006 10:24:49 GMT, "dennis@home"
wrote:


Dishwashers are almost invariably cold fill.

Mine takes water up to 60ºC, so I'd expect some can.

Mine can too ( I think its upto 80C though).
It is cheaper to run on cold and has no effect on cleaning ability.
It may save a few minutes.


Depends largely on the run length of the hot pipe to the dishwasher,
but as the short prewash and first rinse don't have to be so hot, the
initial cooler water from the pipes may not be such a problem.

The prewash and rinses are usually cold.
The final rinse is usually hot to speed up drying.

Doctor Drivel wrote:

wrote in message

... Once the panel circuit fills with water, the pump is only pumping
against the running friction, and not the head.

It is pumping against the head (pressure) always...

Wrong. Eric Hawkins at Powertech Ltd (UK) has been done this for years in lots
of systems with no loss of prime (the vacuum in the Apricus evac tube header
loop above the unpressurized tank) after initial priming. Then again, they
don't shut off the pump at some max water temp. So a "slow draindown system"
with a small hole in the return pipe above the tank water line should work
fine, with a lower flow and higher head to start with and higher flow and
lower head after the pump has pushed all the bubbles out of the underwater
return pipe.

Nick

"daestrom" wrote in message
...

wrote in message
oups.com...
Doctor Drivel wrote:
wrote in message

simpler to have the vent hole above the top of the tank. Add a sleeve
to prevent splash possibility.

It has to be "in" the tank. The pump will squirt water everywhere.

What I'm suggesting is a 1/4" hole in the panel output pipe just above
the top of tank, say 1/2" above. There will be close to no pressure
there, and no possibility of any squirting.


Okay, and if there is no check-valve in the pump or its suction, I can see
that working. Maybe even a baffle just to be sure of little splash.
Shut-off head of the pump will still have to be high enough to initially
fill the collector, but once the return has flooded, less pressure should
be needed to maintain flow.

Now, just need a large enough tank to accomodate the drain-water, and
you're all set.

Although it would take three pipes. A foolproof way is have a tee inside
the tank on the hot pipe from the panels. From this tee take a small bore
pipe up to the same height as the top of the panel and back to the tank.
Vented and no pump over at all. If there is a problem it goes back to the
tank. Pipe is cheap.

Doctor Drivel wrote:

... A foolproof way is have a tee inside the tank on the hot pipe from
the panels. From this tee take a small bore pipe up to the same height
as the top of the panel...

There's no need to go that high. A foot would suffice.

Nick

In message , "Andy Luckman
(AJL Electronics)" writes
In article Zz3Qf.6150$sp4.4886@trnddc01, Gooey TARBALLS
wrote:

And, I suspect I am an A.S.S. (American Senile Sitizen)

Possibly, but a troll certainly. Even an American can't
really be that stupid.

The fact that Bush got re-elected proves that a significant proportion
of them are ...

--
geoff

wrote in message
...
Doctor Drivel wrote:

wrote in message

... Once the panel circuit fills with water, the pump is only pumping
against the running friction, and not the head.

It is pumping against the head (pressure) always...

Wrong. Eric Hawkins at Powertech Ltd (UK)
has been done this for years in lots
of systems with no loss of prime (the vacuum
in the Apricus evac tube header
loop above the unpressurized tank) after initial priming.

I was on about a sealed system, any system whether hearting or whatever.
Hawkins vacuum is not new.

http://powertech-solar.com/article.php?newsID=10


Eric Hawkins is pushing product that is clear. In his house:



- He stripped out the copper pipe in his house and installed plastic. Most
new homes are fitted out in plastic these days, with copper where pipes are
seen. What he thought he would gain with plastic is beyond me,



- He fitted solar panels fitted to a thermal store in his loft/attic. I
have a thermal store in my loft too. Nothing special there.



- He insulated pipes in the loft. All new homes require that exposed pipes
are insulated. Nothing new there.



- He fitted solar panels to heat his thermal store. Nothing new there.



- Now! He stripped out his NG boiler and fitted an air to water heat pump
in the loft. In the UK gas is approx 4 times cheaper than electricity. And
the condensing boilers are very small in physical size and highly efficient.
So a heat pump that "averages" COP 4 would equal a NG boiler in running
cost. NG condensing boilers are cheap (some 26kW version were available from
B&Q for £300 [same as your Home Depot]), heat pumps are not cheap at all.
NO GAIN THERE at all, except a very cold loft, as that is where he is moving
the heat from. No wonder he needs to insulate the hell out his pipes up
there.



- He fitted low temperature underfloor heating in his house. One hell of an
upheaval in an existing house. But nothing new there. Low temperature UFH
is ideal for solar panels.



What he has done is have a thermal store heated by solar panels that heats
wet underfloor heating. For backup he has an air to water heat pump.



He would have been wiser to keep, or update to, a NG condensing boiler.
Much cheaper and guaranteed to give heat when needed, which the heat pump is
not, and then insulate the hell out of his house. Cavity wall insulation is
cheap enough. We have cavities in the UK and this is now very popular with
recent energy price hypes, with government grants too. It is pumped into the
cavity. So a wrap round blanket of insulation. He then could have had
400mm of Warmcell celluloid insulation sprayed on the floor of the loft
(this seals up the ceiling/loft too). Then did some air tight measures
around the house. That would have dropped his heating bills further than his
£180 per ann, with the heat pump and wind turbine. Service for NG boilers
is comprehensive, not so for heat pumps.



The rainwater harvesting is off the shelf stuff. Mandatory in the BenNeLux
countries in new builds. It is worth it I believe with a 7 year payback.
Nothing special there.



PV panels are not new and so far not worth it. Micro turbines in a built up
area are difficult to get permission to erect. They also have long payback
periods, but fine in off-the-grid locations.



His point is: Has the Traditional Boiler Had Its Day? A long time to go
yet. Heat pumps are fine for off the gas grid systems. Even then you have
to do your arithmetic well to justify one. The capital cost of them is
horrendous in the UK. Solar panels a thermal store and low temperature UFH
could be worth it. Unless the air to water heat pump is the same price as a
NG boiler, I would think very hard.

wrote in message
...
Doctor Drivel wrote:

... A foolproof way is have a tee inside the tank on the hot pipe from
the panels. From this tee take a small bore pipe up to the same height
as the top of the panel...

There's no need to go that high. A foot would suffice.

It "probably" would, but I said "foolproof".

Doctor Drivel wrote:

wrote in message

... Once the panel circuit fills with water, the pump is only pumping
against the running friction, and not the head.

It is pumping against the head (pressure) always...

Wrong...

Nick