thermostatic valves

helaus

help - ive just had an energy report (epc) the report states I should have a room thermostat to switch off boiler when temp is reached - BUT i have thermostatic radiator valves - which I thought was best - they also switch off boiler when temp is reached -
the rad valves do switch boiler !!!
anyone have any comment

victor2

How do thermostatic radiator valves switch the boiler on or off?

bob_a_builder

In theory,you shouldn't have rad valves on ALL rad, one rad should normally be left , else if they all shut off you could have a problem due to no flow
and in that case that one rad would keep on taking the heat, of course eventually boiler will overheat and cut itself off, may be running longer than you really need



p.s.- not a builder, so just an opinion

anotherbaldrick

In effect you have a system that works on the boiler stat cutting the boiler in and out and the pump is constantly running . This is very inefficient as the boiler stat may be cutting in the boiler just to keep itself warm not because heat is needed in the house . You really need to get room stats fitted downstairs and upstairs to work in conjunction with your thermo rad valves and the pump. You will then run far more efficiently

Cardew

bob_a_builder wrote: »

In theory,you shouldn't have rad valves on ALL rad, one rad should normally be left , else if they all shut off you could have a problem due to no flow
and in that case that one rad would keep on taking the heat, of course eventually boiler will overheat and cut itself off, may be running longer than you really need



p.s.- not a builder, so just an opinion

Although it is now recommended to have one radiator without a TRV,(in the room with the wall stat) it is perfectly acceptable to have them on all rads if you have an ABV.

The problem with a wall thermostat is that the temperature at that location controls the pump.

I actually have a room stat and TRVs on all radiators and towel rail(with an Automatic Bypass Valve(ABV) it is not necessary to have a one without a TRV)

However I never use my room stat; it is situated in a large hall with stairs leading off. I just turn it up to 28C and the temperature of each room is controlled by the TRV and obviously never reach 28C

I appreciate that it is not perfect in that the pump is running when the CH is on; however a stat in a cool hall is not ideal to determine temperature of other rooms. Similarly if I move the stat into a reception room, why should that determine if heating is off in other rooms?

Don't forget that the boiler stops firing when the water temperature reaches the set level.

helaus

because the rads have got to required heat - the valve closes and therefore no more hot water is required - so boiler switches off

helaus

yes i know about 1 normal valve - but the principle is that once all thermostatic valves close (because temp been achieved) then boiler doesn't need to pump any more hot water so turns off

helaus

anotherbaldrick wrote: »

In effect you have a system that works on the boiler stat cutting the boiler in and out and the pump is constantly running . This is very inefficient as the boiler stat may be cutting in the boiler just to keep itself warm not because heat is needed in the house . You really need to get room stats fitted downstairs and upstairs to work in conjunction with your thermo rad valves and the pump. You will then run far more efficiently

why should boiler be on to keep itself warm - the idea is to heat rooms via radators - also its not possile to more than 1 room thermostat

helaus

anotherbaldrick wrote: »

In effect you have a system that works on the boiler stat cutting the boiler in and out and the pump is constantly running . This is very inefficient as the boiler stat may be cutting in the boiler just to keep itself warm not because heat is needed in the house . You really need to get room stats fitted downstairs and upstairs to work in conjunction with your thermo rad valves and the pump. You will then run far more efficiently

its not possible to have room thermostats and radiator thermostats - either the rad valves turn off the boiler or room stat - they would just be a conflict with such thermostats

helaus

helaus wrote: »

its not possible to have room thermostats and radiator thermostats - either the rad valves turn off the boiler or room stat - they would just be a conflict with such thermostats

if an upstairs thermostat switches boiler off - then why have a thermostat downstairs - IF the system has already been switched off - then the other thermostat cant switch it off again

bob_a_builder

its not possible to have room thermostats and radiator thermostats - either the rad valves turn off the boiler or room stat - they would just be a conflict with such thermostats

or just take the head of the TRV in the same room as the room stat

if an upstairs thermostat switches boiler off - then why have a thermostat downstairs - IF the system has already been switched off - then the other thermostat cant switch it off again

no but if they were wired in parallel it could switch it back on again - no its ok I was only joking

However I never use my room stat; it is situated in a large hall with stairs leading off. I just turn it up to 28C and the temperature of each room is controlled by the TRV and obviously never reach 28C

I have always liked the sound of this approach for a more even consistent temp around the house, but fear (possibly incorrectly) that the system would cost quite a bit more to run that way, but have always meant to have an experiment with that way of operating ( i have all the TRVs fitted, just never got round to it)
pumps probably not rated for near continues operation though, but easy enough to replace