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Discuss Cold Bedroom Radiator in the Central Heating Forum area at

  1. clivestrong

    clivestrong New Member


    The radiator in the master bedroom is often cold while all others are hot. It's the furthest radiator from the boiler upstairs (and the biggest, probably 7ft or so in length). I've tried to bleed it but water there is no air.

    The general fix is pretty easy. Turn the lockshield half a turn clockwise (closing it, I believe) and then turn it half a turn anti-clockwise. A few minutes later, the radiator is hot again (top to bottom). I tend to have to do this every 2-3 days and then it may last for a week or two before I need to do this again.

    New combi-boiler fitted about 3 years ago with a power flush.

    This also happened last winter - can't recall if I had to do it the first year after the new boiler was installed.

    Just curious why I have to adjust the lockshield and return it to the normal position every so often and what could be done to fix this permanently?

  2. Stigster

    Stigster Plumber

    It's possible the washer inside the lockshield valve has come loose and drops down onto its seat restricting or blocking the flow through the rad. By screwing it closed and opening it back up again I think it is "picking up" the washer again and opening the valve. The washer is just about holding in the correct place for a few days then dropping off once more, repeating the failure cycle.

    The fact that the rad works properly after this procedure makes me think the issue is with the valve itself and it needs replacing.
    • Like Like x 2
  3. clivestrong

    clivestrong New Member

    Thanks Stigster. Sounds like I need a plumber in.

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