Which thermostat has priority on heating system?

essexsi_2

Hi all,

I am trying to get my head around how to help set up my parents new British Gas installed heating system. BG are not a good company to deal with nothing but problems !!

The set up has TRV's on all the radiators except the one in the hall which has a programmable room stat.

At present all the TRV's are set to 3 which apparently is 19-21oC. The room stat in the hall is set to 18oC. The boiler stat is set to 80oC.

Which out of all them has priority???

If the room stat has reached temp and shuts the boiler down does that mean all the TRV controlled radiators are off until the temperature drops in the hall to below 18oC and the boiler fires up again!?! Should the room stat always be set higher than the TRVs are set at, for example 23oC?

Thanks a lot for any help.

Si

silvercar

Id the hall generally cooler than other rooms? The way it is set up at the moment, the boiler won't come on if the hall temp is 18C or higher. So if all rooms are the same temp, the rooms won't have a chance to reach any higher. If your hall is generally cooler than other rooms, then the hall dropping below 18C lets the boiler come on and that gives more heat to other rooms.

Given that the hot water in the radiators is still circulating, even if the boiler isn't on, the radiators can still be on even if the hall temp is above 18C.

essexsi_2

hi silvercar thanks for the reply.

The hall is actually quite cold, so the boiler has been on pretty much all day trying to heat that up. The boiler has only been in 2 days so my mum and dad are trying to get their heads around it, with my misguided help!

So the water still circulates around the system even though the boiler is not firing, would that still be hot enough to heat up the other rooms.

Thanks for your help. Si

paulsad

TRV's only control the radiator they are on - the room stat will control the heat in the room it is in. So really I'd set the trv's low or off in rooms you don't use and full on in the room where your stat is - this should be your main living room where you want to be warm in the cold evenings.

paulsad

BY the way I'd move the room stat into your living room - not the hall as you don't actually want to sit in the hall.

stevemcol

80° is OK for your water temp.
Set the hall stat for the temp you want to achieve in the hall then wind down the rad stats to achieve the desired room temperatures. Make sure you hall radiator is fully on. All the stats should then work in harmony.

Paulsad...I don't agree with your advice to put the stat in the living room. It should generally be in a room or space with a non TRV radiator. The hall is generally the best place for a non zoned system.

paulsad

I was looking at it from an economy point of view as in our house its a big old building and I see no point in heating all of it fully (ie rooms we don't generally spend much time in) with gas prices being so high.

stevemcol

Well if you do chose to put the thermostat in a room with a rad stat, you should open that rad stat fully.

paulsad

Understood stevemcol - my lad works as a gas engineer and he always gives us the latest gizmo - the latest wireless stat we can just use freestanding and move as we like. So I appreciate its a problem with a wired in one. In some houses the hall is warm and cozy whereas ours is a large open space bit draughty and all exposed to upstairs so thats why I have mine in the main living space. Plus the mrs likes a cold bedroom - its her age!!!

essexsi_2

Thank you for your input paulsad and stevemcol. I like a bit of a debate as you can learn a lot.

The room stat cannot be moved, but the radiator in the hall has no TRV and is fully on. The upstairs rooms are turned down to 2, just to keep the chill off, and the others downstairs are turned to 3. This seems to be keeping my ma and pa quite happy!!

You are quite right to be thinking of the money saving side as thats why were all here and why my parents paid for the new system. That is what I am aiming for the most cost efficient way of setting this system up for them.

I still do not really understand which of the stats the boiler 'listens' to as a priority?

Really appreciate your help. Cheers Si

iamcornholio

essexsi wrote: »

I still do not really understand which of the stats the boiler 'listens' to as a priority?

The main thermostat in the hall switches the boiler on or off according to its settings

There are no control 'thermostats' on the rads - these are just valves (albeit thermostatically controlled) which open or close at set temperatures and do not control the boiler - just the water in the circuit

The problem with the main thermostat in the hall is that you can potentially have a warm hall and cold rooms. Or the boiler coming on every time the front door is opened and a cold draught blows in

But you could still set the hall temp high (to activate the boiler) and the valves on the radiators will switch off at the room temperatures you set, and then effectively the only radiator getting heat will be the hall one -so this can be economical