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.

In an earlier contribution to this discussion,
hulk hogan wrote:

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.

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
http://content.honeywell.com/uk/homes/systems.htm ) 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.
--
Cheers,
Roger
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On Wed, 19 Sep 2007 14:27:34 +0100, Owain wrote:

hulk hogan wrote:
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?

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

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.



--
Ed Sirett - Property maintainer and registered gas fitter.
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