Central Heating - TRV query

[russell58]

Is it possible to adjust TRV's?

I have two radiators which do get hot but then the radiators cool before the target room temperature is reached (ie the room / general thermostat is still calling for heat). I am wondering if this is because the TRV's are closing at a lower temperature than the target room temperature. The TRV's are set to max. The room thermostat is set to 21 deg C, but the radiators cool before that temperature is reached. As background the system has been balanced and these two radiators have a different make of TRV. The TRV's are Monza by Victorian Plumbing.

Two questions 1) is my diagnosis likely to be right? and 2) can the TRV's be adjusted to respond to a different temperature range they respond - I can't see anything on this.

 

[Harry Bloomfield]

I have two radiators which do get hot but then the radiators cool before the target room temperature is reached (ie the room / general thermostat is still calling for heat). I am wondering if this is because the TRV's are closing at a lower temperature than the target room temperature. The TRV's are set to max.

The thermostat, should not be installed in the same space as a radiator, fitted with a TRV. The simple solution, is to remove the TRV head.

 

[russell58]

The thermostat, should not be installed in the same space as a radiator, fitted with a TRV. The simple solution, is to remove the TRV head.

The thermostat is actually in an adjacent room, which feels warmer than the room than the room with the TRV's. So its difficult to get the room with the TRV's to a comfortable temperature. All the other different rooms the different TRV's work fine.

 

[Harry Bloomfield]

The thermostat is actually in an adjacent room, which feels warmer than the room than the room with the TRV's. So its difficult to get the room with the TRV's to a comfortable temperature. All the other different rooms the different TRV's work fine.

A TRV set on max, is usually not controlling the temperature at all, it is wide open. Assuming no problems with your system - It's seems the room where you have the stat., warms up much quicker/easier, than your problem room. You could try turning the stat up to a higher temperature, or moving it and taking off the TRV of your problem room.

 

[fixitflav]

A TRV set on max, is usually not controlling the temperature at all, it is wide open. Assuming no problems with your system - It's seems the room where you have the stat., warms up much quicker/easier, than your problem room. You could try turning the stat up to a higher temperature, or moving it and taking off the TRV of your problem room.

And check that the rad iso valve (on the other end of the rad from the TRV) is fully open

 

[stem]

The thermostat is actually in an adjacent room, which feels warmer than the room than the room with the TRV's. So its difficult to get the room with the TRV's to a comfortable temperature. All the other different rooms the different TRV's work fine.

I had exactly the same problem when I moved into my present home.

The hall where the room thermostat was located heated up quickly so the central heating was turned off before the rest of the house got warm. I solved it by fitting a smaller radiator in the hall so that it didn't heat up quite so quickly providing enough time for the other rooms to reach their required temperature.

 

[fixitflav]

I had exactly the same problem when I moved into my present home.

The hall where the room thermostat was located heated up quickly so the central heating was turned off before the rest of the house got warm. I solved it by fitting a smaller radiator in the hall so that it didn't heat up quite so quickly providing enough time for the other rooms to reach their required temperature.

You could have just throttled the existing rad

 

[stem]

You could have just throttled the existing rad

Yes, I thought that and tried it when we first moved in, but I couldn't manage to get it right, it wasn't consistent, too hit and miss. Managed to get it right for a few weeks, then when it was really cold and all the other TRV's were fully open it didn't come on at all, so opened it up a fraction to get it on, then later on when the weather warmed a bit it was too hot again. So thought simpler in the long run to change it. 27 years ago now and it works perfectly under all conditions. No fiddling required

 

[russell58]

I had exactly the same problem when I moved into my present home.

The hall where the room thermostat was located heated up quickly so the central heating was turned off before the rest of the house got warm. I solved it by fitting a smaller radiator in the hall so that it didn't heat up quite so quickly providing enough time for the other rooms to reach their required temperature.

Thanks but this is a different problem. The rads aren't going off because the main thermostat is cutting the heating - the main thermostat is calling for heat.

 

[russell58]

A TRV set on max, is usually not controlling the temperature at all, it is wide open. Assuming no problems with your system - It's seems the room where you have the stat., warms up much quicker/easier, than your problem room. You could try turning the stat up to a higher temperature, or moving it and taking off the TRV of your problem room.

Ok thanks good to know a TRV on max is probably not controlling the temperature at all. Now I don't really understand why the radiators in the problem room get hot then cool. The main thermostat in the adjacent room is still calling for heat when this happens so I don't think its the main thermostat cutting heat due to that room being up to temperature. A little bit stuck now. (The isolation valves are open - and I assume the radiators would never get hot if this was the problem)

 

[denso13]

Ok thanks good to know a TRV on max is probably not controlling the temperature at all. Now I don't really understand why the radiators in the problem room get hot then cool. The main thermostat in the adjacent room is still calling for heat when this happens so I don't think its the main thermostat cutting heat due to that room being up to temperature. A little bit stuck now. (The isolation valves are open - and I assume the radiators would never get hot if this was the problem)

Take the TRV head off completely and see if it is any different.

 

[Harry Bloomfield]

The main thermostat in the adjacent room is still calling for heat when this happens so I don't think its the main thermostat cutting heat due to that room being up to temperature.

Sorry, I think I misunderstood your original issue...

If there is still a call for heat from the room stat., and boiler is still producing heat, yet that rad goes cold - the heat must be finding another, easier route back to the boiler.

Do your other radiators remain hot, when that one goes cold?