On Tuesday, 14 November 2017 18:39:54 UTC, T i m wrote:
On Tue, 14 Nov 2017 09:14:55 -0800 (PST), whisky-dave
wrote:
snip
Aren't you the one who seemed to have no idea about any of this?
No I find out by testing not reading the data sheet.
Because you have it in front of you and don't understand the data
sheet?
I understand some of it.
safety information .
1 / Check that the voltage indicated on the rating plate corresponds with that of the local network before connecting the before connecting the applince to the mains supply.
I don't think they are using the term network correct or not as we use it.
Our netword uses cat 6 cable perhaps 6e installed y the networks team who install network cable but they aren't qualified electricians which are a differnt set of individuals as our plumbers and gas workers are.
I understand and can translate the data sheet can you ?
But I can do both, all you can do is read the data sheet.
Yes, because I don't have a rad in front of me (doh!). When I bought a
new rad last year (well, 4 in fact) I did *exactly* what I suggested
and took the end off one and checked out the wiring (and measured the
function). That's how I *know* how yours is doing what it does and you
don't.
I do I can't take them apart they do NOT belong to me or my department.
we have been lent them. I do NOT believe that they have a wiring fault.
It has a thermostat, an overtemp switch / cutout and a thermal fuse.
I do NOT know if it has a thermal fuse did you see it mentioned anywhere ?
These are the actual terms people who know what they are talking about
use to ensure they all understand each other.
https://en.wikipedia.org/wiki/Thermostat
https://en.wikipedia.org/wiki/Therma...Thermal_switch
https://en.wikipedia.org/wiki/Therma...f#Thermal_fuse
None of which appear in the data sheet.
"A thermal switch (sometimes thermal reset or thermal cutout)", no
mention of a 'thermal cut-back' notice.
Which page is that mentioned on ?
I am describing the electrical device as being what it is, whilst you
are trying to conflate that and the function you (you believe) you see
it having.
I know what's happening vai experimentation.
Noo, you observed some effects and others explained what was
happening.
I know what's happening but I didnlt get that knowledge from the data sheet..
You know what should happen hopefully via the data sheet.
I've never seen the data sheets.
perhaps it's time you loked then.
I *know* what is happening from
practical contact with such systems and knowledge of the subject.
Me too.
But that's not what happens because when left on for 2 hours or more it seems when it cuts out the heater still consumes 700 watts.
I know, and I'm not going to explain to you *again* why that happens.
This is what they call the Overheat protection it switches back to 700W.
So it seems.
At last.
So if this heater is left on it;s doen;t produce 2KW of heat it doesn't consume 2KW of electrical power it drops to 700W
No, it doesn't consume nor (therefore) give off 2kW of heat because
the supply voltage won't allow it to.
The supply will allow it, the supply has little to nothing to do with it, it is plugged into the mains supply.
so effectively a 700W heater after two hours NOT a 2KW heater which is what most would assume as it's written on the box and the unit.
Not quite. When you first turn it on and with the thermostat turned to
max and both switches on and plugged into a 240V supply, what current
would it draw and therefore what power would it consume ?
In my office it consumers about ~8amps on switch on. At that moment the voltage is beTween 211 & 213 .
Don;t forget the data sheep spoec that says any voltage from 220-240 the rad will comsume 2KW ;-P
What would you expect a heater with a label that says 220-240 50Hz 2000W to do ?
The cut-out is the Safety tip over switch,
No, there *is a* safety cut-out that (de-)activates when the heater
isn't standing upright.
Yep pretty much says that in the manual and I've tried it and it works
it goes dwon to 0W consumtion when laying on it's side or rather it switchees out at about 40 degrees.
which acutally does cut out or off the electicity supply to the heater giving a reading of 0 Watts.
Yes, that is *another* safety function and only relevant to the
discussion if you knock the heater over. It cuts the power to 0, just
as the main thermostat does.
Yes I know, I've know that all along. I've had one in my office for about 2 years now.
So you can't tell the differnce between those labels is that it. ?
Thermostat, cut-out, resettable fuse.
What? As you don't want to open a unit up and without recourse to a
wiring diagram you would (normally) have no idea which one had
operated if the unit had gone off (as they are all usually in series).
ITRW, if you adjust the main thermostat and it all comes back on, of
leave it to cool down a bit and it comes back on, then the thermal
fuse hasn't blown.
Not blown but reset but rarely happens it seems,
They are not generally self resetting.
But something is, otherwise it wouldnlt go back to 1.7KW .
so the only sure way of getting the heater to again comnsume 2KW is to use a cold air blower (I have another fan heater) to blow cool air over the fins of the 2KW heater.
Yup, because as I explained elsewhere, the radiator is unable to
dissipate sufficient heat fast enough and so 'overheats' and trips
itself (or the just main element in your case it seems) out.
Yes trips out and auto-resets yes. And while in this state it does NOT give out 2KW of heat.
Are you now just trolling mate?
All I'm saying is a 2KW heater won't consume 2KW if yuo leave it on 'full' power
It will if on a suitably rated supply and does initially.
It's always been on a suitabley rated supply.
and does initially.
So the penny has started to drop at long last.
it will drop to 700W
So must have been higher (than 700W) or it wouldn't 'drop' would it?
well done you're almost there now.
so if you're calculating how much heat this unit will give out don't assume you'll always get 2KW because after 2 hours you won't it'll switch down to 700W.
No, it won't 'switch down to 700W', it cycles between 700 and 2000W
(~1600W because of your low voltage) indefinitely until the
temperature set by the thermostat is met.
Nothing to do with the thermostat (the thinbg with the knob on it) that remains at maxium setting .
I;m sorry you are finding this difficult to understand but it really isn't that difficult.
Bwhahahaha. Oh the irony!
Ok, let me see if you can understand a solution I am working on around
the very same issues.
I have a mini oil-filled 450W, thermostatically controlled radiator
(well, 4 actually) that do *exactly* the same thing as yours in that
they cycle on the overtemp stat (because the energy in is the energy
out).
Why is the energy in is the energy out is it becazuse yuor supply isn't up to standard ?
I wouldn't have thought so myself.
So, I was going to design and build a controller that uses an Arduino
Nano, a triac and a couple of external temperature sensors to properly
'manage' the heater. The std heater plugs into my solution.
Are you suggeting that the thermostats on those heaters don't work ?
Temp sensor 1 will be clipped to the heater and will moderate the max
temp of the rad to less than the internal overtemp switch.
why bother.
Temp sensor 2 will measure the ambient temperature of the room.
At start up, both sensors are read and if the value of either is above
their desired setting, the heater stays off.
If the Temps sensor 2 indicates it is lower than the desired
temperature it will apply power to the heater and the maximum
temperature of the heater will be managed by the Arduino in either PWM
(possibly via a PID) or bang bang with some allowance for thermal
overshoot.
Once the room heats up and reaches the setting for Sensor 2, the
heater is turned off again.
Is this because the thermostts don't work ?
You see most people buying these heaters arent; likey to set up an arduino adn why you'd use a nano I don't know I'd use one of the new Arduino PRIMO so you can control it wirelessly.
The *reason* for doing that is we only need a small heater in the
bedroom but both the overtemp stat and thermostat are quite noisy,
hence the electronic solution.
well noise isn't our concern the amount of heat supplied is more important.
As an alternative / experiment I intend wiring two heaters in
*series*, as that way I will still have my 450W (2 x 225) but the
heaters may then be able to dissipate the lower energy without cycling
on the overtemp stat. Then I could use a std plug-in electronic timer
/ stat and save all the building bit (I'd just need to set the rad
stats to a level *above* my desired room temperature).
So what made you choose 450W heater ?
What's wrong with 2KW or 2.5KW which I use at home.
So, do you still think I don't understand exactly what is going on
with your setup?
Yes I still think that, going by what you've said.
What measurements, most situations you decide what you want before taking measurements, because yuo buy based on teh specifications of the product.
Not in this case you shouldn't (tail wagging the dog) and John has
explained the process clearly enough elsewhere.
And that would fail in this case.
Doing the calculations should be step one mate, not step two.
Shouldn't be a step for me or anyone else here.
Can you show yuor calculations for step 1 ?
What has
actually failed is the particular solution you are trying to implement
(and possibly including a design / wiring fault).
Design fault YES (at last) wiring faulty NO.
But I don't believe they are useless if you understand how they work.
Bwhahaha ... I understand how they work mate ... ;-)
Not shown much evidence of that yet, well not a true understanding, perhaps a casual users understanding like those that ordered them who have degrees in managment but can't tell a plug from a socket.
You bought a car to tow a trailer but with no idea how big the trailer
was.
I know how big the trailer is I just didn't expect the car to go from say 2000 HP to 700 HP.
And if it did you would contact the supplier and ask why eh?
That would depend on the car and the cost of that car.
I'd assume NOT but you seem to think it would, and I don't understand why.
I know you don't, in spite of me explaining it several times and
suggesting you check one yourself (wiring) and contact the supplier /
manufacturer.
Not interested when 3 of the 5 all do the same just like it says in the supplied manual.
I'll try one more time and in simple terms even you should be able to
understand ...
You've just lost the plot that's all.
\
(Potentially ...) The heater has the ability to give off something
*less* than the maximum it can consume (even when that is only 1600W)
because the heater power is too big for it's surface area. The end.
Well ****ing done at last, so how would you calculate how many heaters would be needed if the heaters you brought can only dissapate the stated heat for about 2 hours then switch down to a 1/3 of their rated value ?
Explain it to me, if you do really understand this.
So, if you stuck a diode in series with the heater and reduced it's
power by 50%, the chances are it wouldn't 'cut out' (the main element)
... cut-back in power (because of how it's wired) and you would be
happy.
I would NOT be happy buying a 2KW heater just to reduce it to 1KW with a diode in the hope it didn't drop to 700W.
The thermostat is meant to control both the amount of current heating the eliment and therfore the amount of heat generated or whay donlt yuo explain what the thermostat is for.
If yuo look in ther manual it tells you how to set these units up using the thermostat rather than the over heat protection or the trip out.
so how would an engineer predict what sort of heater and what power would be required ?
See Johns replies for an answer on those.
doesnt give the answer and shows exactly what I predict a wrong result due to lack of actual knowledge.
No, it gives you the number you do still need to allow you to
determine if the goal is achievable or not.
So how woul yuo work that out if 2KW heaters all reduce to 700W after 2 hours ?
This is the key point the point you keep missing.
Lets try this again a 2KW heater is consuming 700W of electrical power so I assume if is giving nout less than 2KW of heat.
Unless of course tyuo believe these £25 rads are the answer to propectual montion or similar where 700W of electrical power can produce the same heating effect as 2KW of electrical power.
Is that really what you believe ?
Suppose he was told that 10KW heater would be required to do what he wanted and then on installign them, he found that after a while the 5x2KW were no longer 2KW but reduced in power to 700W, would that change any calculation,
Of course?
AT LAST the pennies dropped.
With you, hopefully! It wouldn't change the calcs for the requirement
Yes it would change what was needed.
but it would change the calcs for the / your solution.
So can you show me where this is indicated on the web site. ?
Ok ...
PLease make sure you chek all links before answering.
Yes Sir! (P.s. Do you have my bank details to pay me for doing this
for you)?
Not that'll post.
http://cpc.farnell.com/pro-elec/pel0...ack/dp/HG00575
http://www.farnell.com/datasheets/2339828.pdf
As I have explained (at length):
"This heater includes an overheat protection system that shuts off the
heater when parts of the heater are getting excessively hot."
and that will happen nif yuo have the heater on full.
So a 2KW heater after 2 hours turns into a 700W heater how many times do you need telling ?
Except is doesn't does it, it cuts *part* of the heater off (also as I
have explained at length).
http://www.easyflip.co.uk/CPC_Digita...gue/?page=1906
You have a oil filled radiator that has the potential of giving 2000w
exactly a potential that is only reached for 2 hours for the rest of the day/night it will be a 700W heater have you got that yet.
worth of heat continuously, as long as the heater is in a cold enough
environment (or the convection efficiency improved by putting it in an
airflow) to ensure the radiator doesn't 'overheat'.
so the heater can't or isnlt cable of truelly dissapating the heat for more than two hours so it turns into a 700W heater which for the rest of the day only dissapates 700W of heat have you understood this yet.
A 2KW heater is a 2KW heater for 2 hours then it 'morphes' into a 700W heater
Why is this difficult to understand, if I want a 700W heater I;d buy a cheaper smaller heater.
HTH (finally).
Cheers, T i m