Electric heating thermostat

[john4703]

I’m looking for some advice about thermostats for electric convector heating. I’ve got a caravan with electric heating. It has two completely separate heaters. One is either 750 watts or 1500 watts so it uses 3.25 or 6.5 amps.

The other heater has three power settings 500 watt, 1kw and 2kw so current ranges from about 2 amp to 9 amp.

I want to fit wo separate wall mounted thermostats to control these heaters. In both cases it would be good to be able to leave them set at 4 or 5 degrees to protect against frost when the caravan is not being used and to be able to set a comfortable temperature when we are using it.

I’d like a nice accurate digital display if possible but what I really want is the experts’ recommendation of decent thermostats fort these loads. I could fit contactors but with such low loads I’d rather have a thermostat that can handle the range of currents involved.

 

[copea]

Honeywell DT90E (wired) can handle an 8A load, and the DT92E (wireless) can handle a 5A load.
I think I'd rather use a contactor/relay though, as they're not normally used to switch such large loads. I would imagine they wouldn't last long at the upper limits.

EDIT: Or an underfloor heating controller with an air temperature sensor? They're designed to deal with larger loads...

 

[stem]

I have had a Salus RT500rf controlling a 2kW heater in my conservatory for 3 years without a problem, in fact it was the first Salus I had ever used and I chose it specifically because its was the only one I could find with switching contacts rated at 16A. It can't be set to operate as low as 5 degrees, but it does have a frost setting which when selected, it will override the programmed settings and turn on the heating at 5 degrees. This model has recently been updated to the RT510rf, which I don't have experience of, but looking at the literature, its current rating is still given as being the same.

Salus do also make wired thermostats, but for some reason their current rating is lower.

I know there are some on here that don't rate Salus products too highly, but I have installed several RT500rf without any problems. Most problems occur because either the distance between the thermostat and receiver is too great, or obstructed. Which, unless your caravan is massive is unlikely. Or, the unit has been left on the factory set RF address code and is being interfered with by another unit also on the same address code. If you had two receivers, you would have set them differently anyway. Unless of course, you wanted just to use one thermostat to operate both receivers.

You don't say what type of electric heating you have, but I'm assuming that it is resistive. Most thermostat specifications. Including the Honeywell mentioned by copea above, give a resistive rating which is fine for electric heating elements, and a lower rating usually shown in ( ) for an inductive rating, which would apply if the unit was being used to control a large motor for example.

 

[john4703]

Thanks for the replies. It is a resistive load as both heaters are convector heaters so no problem with that. I'll look at the suggestions and work out which will fit the situation best. The Honeywell wired will certainly handle the 1.5kw and that is the one that is easiest to change and most urgent as i like to leave that on while the caravan is parked at my house but don’t want a massive bill, or frozen pipes in that part of the ‘van.