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  • Re: TRV valve stem movement

    From Tricky Dicky@21:1/5 to Andy Burns on Sun Mar 16 15:59:19 2025
    Andy Burns <[email protected]> wrote:
    Tricky Dicky wrote:

    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

    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

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  • From Tricky Dicky@21:1/5 to All on Sun Mar 16 15:37:21 2025
    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

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  • From Andy Burns@21:1/5 to Tricky Dicky on Sun Mar 16 15:52:01 2025
    Tricky Dicky wrote:

    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

    On a spare Myson TRV sitting here, the protrusion is a little more, but
    the movement is about the same ...

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  • From Tim+@21:1/5 to Dicky on Sun Mar 16 16:54:29 2025
    Tricky Dicky <[email protected]> wrote:

    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



    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

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  • From alan_m@21:1/5 to Tricky Dicky on Sun Mar 16 17:36:51 2025
    On 16/03/2025 15:37, Tricky Dicky wrote:

    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



    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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