My heating system has reported that one of the TRVs is not fully shutting off and I have found the radiator getting warm when it should be off. I have carried out the recommended service of moving the stem and adding some silicone lubricant. My question is how much movement should there be in the valve stem it protrudes approximately 3mm above the valve and there is about 2mm of movement, is this normal or am I looking at replacing the valve body?
Richard
On a spare Myson TRV sitting here, the protrusion is a little more, but the movement is about the same ...
Thanks Andy the protrusion on second look could be slightly more than 3mm as I did not measure it and it was just by eye guess. It is reassuring that the movement is correct.
Richard
Check that the TRV body is properly seated on the valve body and not cross threaded. It only needs to be off by 1mm to prevent the valve shutting fully.
Tim
That sounds like about a normal movement. Have you got a decorators cap that you can put on it in place of the head? If so does that keep the radiator cold? Are you sure that you have installed the head on the body correctly? Put the temperature to the highest setting, fully undo the retaining screw ring, push down on the head to firmly to seat the head on the body before doing up the retaining screw ring.
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