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Discuss Uponor UFH, do i have a stuck valve? in the Underfloor Heating Forum area at

  1. johnny1drink

    johnny1drink New Member

    Hi all,
    Thanks all in advance for any advice! (excuse my terminology - I am a basic DIY-er, but like to work things out)

    I have a wet uponor UFH system. I am getting hot water to the valve in the picture attached, but it is not passing through the valve to the underfloor pipework. The underfloor system is calling for heat - the pump is triggering when the thermostats call for heat, but i cant get the hot water to feed. So in essence, the system is pumping round room temperature water (20c), and is not getting the top up from my hot water inflow.

    i THINK the problem is this valve (is it called a manifold?). Hot water will not pass through. I have removed the casing, and the pin does operate freely up and down (whatever that does?!). I have also taken a photo of the inside as best i can. How do i know if this is broken? Is it as simple as replacing this part? I can isolate the flow with a valve upstream, would I just remove & replace?!

    HELP (cold and frustrated)

  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

  3. Chalked

    Chalked Plumber GSR

    The thermostatic valve could be stuck, the pump could be seized, the heads or flow restrictors could be blocked/ stuck. Or there could be a problem with the thermal heads not working/ getting power.
    All this needs systematically testing to see where the fault lies.
  4. Ric2013

    Ric2013 Plumber

    Does the OP have two thermostatic valves?
    There is a Tapstat/ Drayton RAVI type thing, plus the blue Uponor mixing valve. Am I wrong?
    This seems unusual. I wonder if the Uponor valve has previously failed and the Tapstat-type thing was a workaround?
  5. Chalked

    Chalked Plumber GSR

    Some Uponor manifolds have the thermostatic valve like that. It remote senses the manifold flow temp.
    • Like Like x 1
  6. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    in the second pic does the pin move up and down easily ?
  7. johnny1drink

    johnny1drink New Member

    Now fixed.
    Thanks all, in the end i troubleshooted valve by valve, one of the nuts had an allum key and i was able to free the flow by turning that. I'm not sure what or how, but its fixed.

    I will definitely tap this forum in the future, great find!
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