Radiator TRV Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[mblago]

Need some advice please. The TRV's in my 3 bedrooms upstairs come on in even when they are turned off, will they all need to be changed or could it be something else?, also if they need to be changed, is it an easy job to do. many thanks in advance.
Mike

[plumbbob]

Three points. Firstly, older TRV's didn't actually have an off setting. IF you look at the valve and the lowest setting is a * (snowflake) this is a frost setting, and whilst in the summer may pretty well switch off, still may allow a minimal flow if the room is cold. Only valves with a 0 (Zero) setting guarantees an off.

Secondly, as valves age, scale and deposits build up on the seal surface preventing the valve from shutting fully.

Lastly, the head may fail causing the valve to stay open.

All older style TRV's were supplied with a cap that replaced the thermostatic head and allowed the valve to be shut manually. Of course, these are always lost!

Unfortunately, replacement is the only cure.