TRV's + Room Thermostat?!

bpk101

We've just had wet underfloor heating installed in our new kitchen. We have a wall mounted thermostat in the kitchen to control the UFH.

Our builder has advised us that we should now get a room thermostat for the main house (possibly positioned in the open plan lounge / diner are) even though we have TRV's on all the radiators.

I think his logic was that we're better off having a master room stat controlling the temperature in the house rather than having to run round adjusting individual TRV's.

He says although we can turn off the UFH in the kitchen via it's own thermostat (which we would do every day during hours we're out at work), the boiler will be constantly feeding the radiators in the rest of the house unless we dash round and turn all the TRV's off (or down low) each morning.

I can see the sense but i always though TRV's + Room Thermostat was a big no?

bob_a_builder

"but i always though TRV's + Room Thermostat was a big no?"

No,No in the same room ! - otherwise no issue - so just take the TRV head off the rad in the room you fit the stat it

chappers

doesn't really matter, the master stat controls whether the boiler feeds to the rads via the motorised valve whereas the TRVs turn off individual rads.
So if you have a thermostat and TRVs you will still need to adjust each one accordingly.
If the stat is in a room with a rad on flat out, the boiler will keep sending heat to the rads until the stat tells it to stop then it will shut heat off to all the rads, up until that point (whilst the heat is sent to the rads) each other radiator will heat up as per it's TRV setting.

If the TRV in the room with the stat is set lower than the stat then heat will be sent to all the rads until their TRV heat is achieved as the room with the stat won't get hot enough because the TRV will cut it off and won't shut off the heat to the boiler loop.

Chrishazle

When we had our CH overhauled in the old house in 1983 I was also told I could not have an area stat as the fan rads we were installing in some rooms had their own thermostats so we had to have TRV's on the remaining normal rads. I was therefore surprised when we moved to this house - with gas CH installed in 2003 - to find TRV's on all rads and an area stat at one end of the hall by the lounge door - and an ordinary rad with TRV at the other end of the hall by the front door! There's also a bypass loop in the airing cupboard (where the pump and CH/Hot Water control valves are) so when both control valves close water can still circulate back to the boiler until it sools down enought for the boiler and pump to switch off. Mostly I keep the area stat set to 25C so the TRV's control the temp in each room, especially when we have the wood burner going in the lounge as that can trip the area stat and turn the boiler off - rest of the house then gets cool! However, we do find times when we turn the area stat down as, even though the TRV's are set to 1 1/2-2 (3 is supposed to be 68F) the house can get too warm.