Mad central heating logic !!!

7 Mar 2005
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United Kingdom
Can someonwe please explain the logic behind the central heating system in my new house?

The condenser boilder has 2 zones.......

Zone 1 is for the downstairs (except hall) and is controlled by a thermostat in the lounge which has 2 radiators without TRVs. All the other downstairs rads have TRVs fitted. The problem is, in order to keep the house warm I have to set the lounge thermostat very high. The lounge is not usually used during the day and with the door shut it heats up quite quickly, reaches thermostat temperature and cuts off the heat to the rest of downstairs.

Zone 2 is for the TRV radiators upstairs and is controlled by a thermostat in the hall with a single non-TRV radiator adjacent. I have nearly closed off the valve on this rad but still the thermostat reaches temperature quite quickly (mainly from the downstairs rads) and so shuts off heat to upstairs. The only way round this is to set the hall thermostat to a very high setting so that the bedrooms have heat if the TRVs need it.

It all seems weird to me. I am thinking of fitting TRVs to the lounge rads and leaving it's thermostat on very high. The lounge rads will then turn-off at their set temperature but the thermostat will still run the rest of the downstairs zone as required.

Upstairs I can't think of anything besides buying a remote wireless thermostat and fitting it in the coldest bedroom. This room hardly gets warm as the hall thermostat has turned off long before it's had any time to get heated.

Any thoughts would be really appreciated as it just seems plain daft to me!

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it just seems plain daft to me!
You aren't alone.

Stat in the hall upstairs ??? OK if you leave all the bedroom doors open - maybe. Sounds, yes, daft.
All I can think of at this hour is to put stats in each bedroom set carefully to just below the trv temperature, connected in parallel so that any stat will bring the zone on, with the room temps being controlled by the trvs.

Downstairs turn down the rad valve(s) on the un-trv'd rads and they'll be slow to heat up and those with trv's will get enough hw through to work.
"turned down" may mean just 1/3rd of a turn open. Try nearly shut and work up over several warm-up cycles.
Thanks for the reply, just to clarify the stat for the upstairs zone is downstairs in the hall not on the upstairs landing.

I have already very nearly shut off the un-trv rad in the hallway so the stat keeps the heating on for longer allowing the upstairs rads to run up to their trv temperature.

Also I have bumped up the lounge stat to about 24 (!!) so again the rest of the downstairs zone has time to get to their trv temperature.

The problem is with both these solutions is that the lounge is now toasty warm and stays that way while people move in and out of the kitchen, hall,dining room etc and they get gradually colder.

Similarly the downstairs hall gets warm from rest of the downstairs rads and so the upstairs gets gradually cooler.

I think I may have to put trvs on the lounge rads and just run the stat hot. The boiler has a Danfoss auto bypass valve fitted so I don't think that will cause a problem. Similarly I could put a trv on the hallway rad or just follow your advice and keep it nearly closed off.

I am also considering moving the upstairs zone stat from the downstairs hall into the coldest bedroom. However, the wiring would not be easy and the RF type remote stats are not cheap.

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