Temperature alone doesn't dictate how warm a house is, as high or low humidity will impact how warm or cold it feels
We set out thermostat to 9c, when we turn it on it gets set to 20c. We don't use timers so it's just on when we want it, otherwise it comes on if my loft based sensor shows it's 3C to get some water circulating round the pipes
I've posted this before but it's worth knowing as many people have TRV's but don't understand them
Numbers & temperatures
The numbers on the valve roughly correlate to the room temperatures below. When the room drops below these temperatures, the TRV will allow hot water to flow into the radiator:
- 0 = Off
- * = 7°C
- 1 = 10°C
- 2 = 15°C
- 3 = 20°C
- 4 = 25°C
- 5 = 30°C
A fully functional TRV will detect the temperature of the room and automatically adjust the amount of hot water in the radiator accordingly.
During the winter, you should really set your TRV to 2 or 3 and leave it. If you go into a room that's cold and the radiator is burning hot, leave it alone and don't turn it up to 5. Let it do it's job and allow the TRV to heat the room accordingly.
(If you're away for a long time in winter, set your TRVs to * so that the rads will come on for a short while if the temp gets below 7°C)
Use TRVs properly to save money
If you turn a TRV up to 5, basically you are telling it not to stop letting hot water into the radiator until the room reaches a very very high temperature (around 30°C). If the temperature drops below 30 degrees, water will be hot allowed into the radiator.
This is unnecessary as you rarely need the room to be that hot and it also means you lose any savings you may have otherwise made on heating bills because the hot water will be constantly flowing.
The best way to use thermostatic radiator valves is to decide on a comfortable room temperature and set the number on the TRV accordingly.
Regularly changing the settings on a TRV is not recommended and will undermine their money saving qualities, which is one of the main benefits of installing them in the first place.
There are several things that can cause problems with TRV’s, but as they are relatively simple devices it is not too difficult to diagnose the problem. It is recommended to maintain them to ensure that they last and perform well.
The most common problem with a TRV is that the valve sticks or catches. This means that they are either stuck open or closed. This will happen when the setting has not been moved for some time, such as after the summer.
Solution and Maintenance: Set the TRV to the highest heat setting (generally number 5) which will open the valve fully. Then undo the thermostat removal nut, which you should be able to do by hand. When the thermostat unit comes off, you should see the little plunger or piston, which should be able to be depressed and then should spring back up when released. If this is very stiff or catching, give it a little squirt of WD40 and work it a little until it slides freely. An annual check and squirt of WD40 is advisable to keep the TRV working efficiently.
If you cannot get the plunger working again, then the valve has failed and will need to be replaced completely. See below section on how to change a TRV for help with this.
The second problem that can occur is that the thermostat can fail. If the valve is working, and the plunger is moving freely, it is likely that the thermostat is not depressing and releasing the plunger, therefore opening and closing valve as it should. The thermostats is relatively simple which uses a trapped bubble of gas, liquid or wax to expand and contract with the change in temperature of the room to move the plunger.
Solution and Maintenance: If the thermostat has stopped working there is nothing you can do except replace it. Before you do buy a new one it is worth making sure that this is the problem, but swapping the thermostat with a working TRV and confirming that the valve now works.
For general maintenance of your TRV it is worth opening and closing the TRV fully several times to get the mechanism working. Do this several times per year to stop the plunger or piston seizing up.
