On Fri, 07 May 2004 18:50:55 +0100, Daern's Instant Fortress wrote:

I'm after a little bit of impartial advice on my recent CH upgrade. It's a
bit of along tale, but quite simple in truth...

Our old CH system used a single room (house?) thermostat, located in the
hall. The radiators did not have thermostats fitted. Our house has a very
large conservatory, which was heated by a CH fed convector. Unfortunately,
because the room 'stat at the other end of the house would always turn off
before the conservatory was warm, we would be left with either a warm house
and cold conservatory or, after turning the 'stat up, a warm conservatory
and a _very_ warm house :-(

I've now had a Worscester Bosch 35CDi II combi fitted to replace my
(somewhat ageing) gravity fed boiler as part of some work we are having done
on the house.

Because of the conservatory problem, we have decided to remove the room
'stat and use radiator thermostats on all of the radiators, bar a single one
near the boiler. This should (apparently) allow each room to maintain its
own temperature and once the whole system reaches temperature, the system
will shut off because the returned water feed is at the same temperature as
the outgoing feed (apparently this is because it's heating only one
radiator).

I suppose my question is - is this a good plan, or am I going down the
totally wrong road? What considerations should I be making here? Can I run a
combi CH system without a house 'stat?

Thanks in advance for any help you can offer me - as you have probably
gathered, I know very little about plumbing ;-)


The very best way would be to zone the conservatory independantly fromt the
rest of the house heating.

TRVs on cooler rooms is no bad thing.

However the arrangement you outline
assumes that you want to heat the conservatory whenever you heat the house
and to much the same sort of level.
If you can arrange for the conservatory to be independantly heated you can
opt for such things as having it mildly heated for plants even when you
are out or away. Alternatively you might want to avoid heating the
conservatory entirely in deep-winter? Again you will probably want your
heating system to stop heating the conservatory when the sun shines as
such locations are apt to have a large solar gain.

Depending on how the pipes are laid and the state of decor the ease of
doing what you want will vary. In essence you would block off the existing
feed to the conservatory then connect a new feed pipe from before the
first T to feed any house radiators. Both the existing pipework and the new
pipe would then have there own valves to control them independantly.
A programmable thermostat would be used to control the conservatory.

I guess others will want to give you their own 2ps.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html