Thermostatic Radiator Valves

[Bonzo 2000]

We've recently bought a house with thermostatic valves on each radiator. Some of them dont work and seem to remain fully on or fully off regardless of the setting. Sometimes a good whack on the side wityh a wrench seems to free them up, but I cant imagine this is doing any good. Does anyone have any good tips to service these things?

[sddsddean]

If the heating has been off for a while, they do stick. I always have 1 or 2 stick come winter. Rather than whacking them with a wrench(!), unscrew the knurled collar at the bottom of the plastic bit and lift the whole plastic bit off. You will see a pin about 1mm in diameter in the top of the brass fitting. Tap this VERY gently with a small hammer, just enough to release it (you should see it pop up a couple of mm's). Screw the plastic bit back on. After that it should work OK once the heating is back on and the valve is being 'worked'.

[fazer]

TRVs will not control the temperature of the water in the radiator, so the radiator will either appear to be on or off! What TRVs do, is sense the temperature of the air in the room, once the air in a room reaches the desired temperature a wax valve within the valve expands and closes the valve stopping the hot water from going into the radiator. As the room cools down, the wax contracts and opens the valve, hence keeping the room at the set temperature. They can be quite slow to react though! From what you have described they are working as they should! I do not recommend that you hit them with a wrench as this could cause leaks on your system and possibly lead to flooding your house :)

As sddsddean has said, they do have a tendancy to stick every now and then just do as he said and you will fix this problem! But as I said I dont think you have a problem.