Thermostat for panel heater

Hi
I have panel heaters (1250w creda) with a pilot wire. The control centre that utilised the pilot wire is no longer available. Can I connect the pilot wire to a receiver for a programmable room thermostat?

Likely yes but would need to look at the data sheet for that heater, Creda 1250 watt is not enough. I did try looking but got and to find the manual for your heater one needs the info, so seems better if you down load the manual your self.

Some of the old fashioned CH room stats had 5A contacts. I use a couple for small heaters. I think they are still available.

Thanks and meant to the model - apologies - heater is creda eph1250, manual is attached. Currently the heater is connected to a FCU. My thoughts- remove the wiring from the FCU. Run a cable from the receiver into the FCU to power the receiver. Wire the heater into the receiver - will a receiver cope with power of heater? Which terminal on a receiver would the pilot wire go into? I have used Drayton digistat SCR and room thermostat on a GCH system before and would like to use those again if possible. I have also attached the manual for the creda zone controller which is no longer available but is what I would like to achieve using a wireless room thermostat and receiver (just for one heater)

The Moes BHT 002 series has a version for electric underfloor heating with 16 amp contacts. However just read the linked instructions, and the pilot wires is not connected to a thermostat, it is used to switch the heater between comfort (no power) and Eco (powered) so you can turn multi-heaters down when leaving the house for over 2 hours.

I have the same with my Nest thermostat, I can set the Eco and Comfort temperatures so geofencing can auto turn down the heating when I leave the house, and turn it back up when I am returning.

So it seems the heater has a built in thermostat. Again same with my central heating, all my radiators have TRV heads which control the radiators, the whole idea is natural thermals in a room will mean air returning to the radiator is a true indication as to room temperature. As to if that's what we want is another matter, my TRV says the room is at 17ºC and 16.3ºC, but in real terms it is more like 19ºC as I have an old TRV on the mantle place which is still reporting. Try moving a thermometer around a room and one can get many different readings depending on height and position, I know my mothers house the living room caught the sun with a bay window, and have recorded 32ºC near window and 16ºC at the back of the room at same height.

So we need to allow for this, and this can mean setting the thermostat at what seems the wrong temperature, my hall TRV shows 16ºC and the wall thermostat in the same room shows 18.5ºC but come summer when heating not in use, they show the same.

What the early mechanical TRV heads did was have a dial marked * 1 2 3 4 5 6 which seemed about as good as a chocolate fire guard, but it was because the temperature at the radiator where it is measured is not what the actual room temperature is, so one is told to adjust until at required temperature so you select likely a lot lower than what you would if marked in degrees C.

So you can get a geofencing relay, I note Energenie do one, the MIHO015, but to be frank I have turned off the geofencing on my TRV's and wall thermostat, as the room does not heat up fast enough. Using a Sonoff relay to turn the heating up/down remotely may be a good idea, these may well work, but clearly it needs to be put in a box some where, as it has live terminals. The data sheet is not that plain as to how the trigger wire is powered, it states 230 volt, but it seems the unit has 4 modes, off, frost, eco, comfort, and it not clear how it works all 4 with a single wire, it does say if not connected it defaults to comfort, but not how the other three are selected if not using the PW E4ZC.

@ericmark
Surely the TRV next to a radiator should be reading a higher temp not lower.

Thanks again. Yes the heaters have a built in thermostat. I have relooked at the manual for the controller that was available and I misunderstood - there is no temperature control on that as you said. However, my further thoughts:
The pilot wire is ‘dumb’ - it waits for a signal to turn the heater on or off. Surely this signal can come from a thermostat receiver. The receiver will only send the signal to the pilot wire when the room thermostat tells it to

Mister Banks said:

@ericmark
Surely the TRV next to a radiator should be reading a higher temp not lower.

Click to expand...

No although I note the energenie one claims to have a water sensor to compensate for the heat from the radiator direct, but once the thermals are started the hot air rising draws in cold are to bottom of radiator.

garyslater said:

The receiver will only send the signal to the pilot wire when the room thermostat tells it to

Click to expand...

Not really, making the pilot line reduced the temperature setting at the heater, one could fit a thermostat to the supply, but it would need to be double pole as the heater is class II so since very few if any thermostats are double pole it would need a relay, and can't see it is worth all the messing around.

Putting it simple I would not want to heat the home with electric to start with, so maybe I am not the right person to ask, the reason why I have worked out how the home is heated, is my own heating is not working as it should. So I have gone around with thermometers to see what is going on. My first house was hot air, worked great but expensive to run, but since it worked never really played with it, second house upstairs got too hot, fitted TRV's upstairs, then all worked A1 so again forgot about it, it worked so why worry.

So not until I went to look after mother with a house with internal doors down stairs, did I come across a heating which did not heat the house as wanted, some rooms hot and some rooms cool. And I started to look at how a home should be heated. Pictures like this are not really helpful as today most windows are double glazed, however it does show how the heat should be on the internal wall, not next to window, and for some reason we have traditionally fitted heaters under the window, maybe because can't put furniture there? This one tries to show how it circulates and how under the heater is a good place to monitor air temperature, however the building regulations stipulate the height of the thermostat on the wall at a position where we can both see it and access it, and say it should be on opposite wall to heater, mainly one assumes as placed so high, but today the wall thermostat is more like a hub, taking demands for heat from the electronic TRV heads, but this is because we have a central heating boiler which has a minimum and maximum output, with electric panel heaters it should be simple, the thermostat is built into the heater, no need to mess around, I had something similar with my Myson fan assisted heater on my old central heating.

The main problem today is to stop all the thermostats fighting each other, set at different heights in the room, they will not show same temperature, and the difference changes with the temperature outside, summer no heating on all mine show same temperature, but winter there can be a wide variation.

With central heating the answer is analogue control, this is far better than digital (on/off) there has been attempts with digital to use a mark/space ratio to start switching the heater on/off/on/off and as the temperature gets closer to the target to increase the off and decrease on time, to try to emulate analogue control and reduce the hysteresis, but this means the contacts wear out quicker, using semi-conductors one can change how much heat is released, but in real terms easier to fit the heater with oil to damp down the difference between on and off.

There is a balance the storage heater takes too long to re-heat a room, the delay between turning on power and getting heat is too long, the inferred heater is the opposite heat felt immediately, but also cold felt intermediately when switched off, it will vary room to room and home to home which is the best, but in general the oil filled radiator is about the best compromise with resistive heating, but clearly running costs drop using a heat pump.

My Wiser TRV’s read warmer than the actual room temperature so they might indicate the temperature is 20c but actual room temperature is 18c but when the heating is off the temperatures match quite closely.

I have a garden room which is heated by two Dimplex electric panel heaters and have also been looking for a better way to control them. I think the Drayton Wiser electric heat switch is closest I have found but you need not just the switch but also a room thermostat and hub. Overall cost is about £140 for one heater but each additional switch would only cost £40.

@ericmark - thanks again. Given a choice I wouldn’t heat with electric either but live in new build house with ASHP which works well to the underfloor downstairs but builders put panel heaters upstairs which aren’t that easy to fine control according to room temperature. This means we don’t have them on consistently and so huge fluctuations in temperature. I could just upgrade the heater to one with better programming but limited space and furniture arranged around heater position - can’t find one that is the right size.
@Mister Banks - thanks- will look at this

I remember one place I worked we had heater control problems, the rapid switching around once a minute caused the contacts to wear out quickly, so we used a solid state relay. And in my home now the domest hot water is heated with an iboost+ which can control the immersion heater 200 to 3000 watt, so the technology is there.

We have inverter drives, soft starts etc. So there should be something to control a little heater. I suspect that there is an electric under floor thermostat that will do the job, but been retired too long to know what is around today.

UPDATE: I have now installed the Drayton Wiser hub, electrical switch and thermostat. Will post in DIY projects