Question on Room Thermostats

[hulk hogan]

When installing gas central heating, is it possible/easy to install a system where the the temperature in each room is controlled via a programmable thermostat? I suppose the basic system would be to have a TRV on each radiator in each room, and adjust these to obtain the temperature you want. Multiple radiators in a room makes this more fiddly. And you can't control temperature settings by time period.

Or do I have the point of room thermostats wrong, and is it the case that generally a room thermostat is used as a global on-off switch for the entire system, but designed to control the temperature in the 'most important' room? If there was a thermostat controlling each room, would it connect to some valve that would cut off water to all the radiators in that room? I realise these are kind of vague questions, but I'd like to know the possibilities over and above just using TRVs. Thanks for any input.

[Owain]

Yes. You have each room (multiple radiators if you want) as a separate zone.

The cost of multiple zone valves and programmable stats soon mounts up though, as does the inconvenience of going round reprogramming each one.

Owain

[Roger Mills]

The most common systems have just one room thermostat, which turns the lot on and off, in conjunction with TRVs on most of the radiators. This works more or less ok, but is of course a compromise.

If you want proper independent control of each room, you need something like an S-Plan+ system (see

) with a separate zone for each room. That implies one room stat and one motorised valve per room - all wired up such that whenever one or more rooms are demanding heat, the boiler and pump fire up. Gets a bit expensive though!

It could probably more easily be done if you controlled the whole thing with a computer. You would then only need a sensor in each room rather than a programmable stat, and you could probably control the flow with the sort of radiator valves which are like TRVs with electrical heaters built in, which heat the wax element and close the valve. You could then program the whole lot from a central point.

[Ed Sirett]

That level of zoning would come expensive. However if the matters are dealt with at the design stage a couple or three heating zones in a house is plausible.

You are right the (programmable) wall thermostat is the global time and temperature control and TRVs are used to fine tune the rooms. The trick is to get the wall themrostat in just the right place that it... 1) represents the overall temperature of the house or zone of the house. 2) is not subject to influences like sunshine, fires, cooking or bathing. 3) is a little behind the rest of the house so that everywhere is warm enough when it cuts out.

4) is conveniently sited.