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Discuss Wet underfloor heating problem in the Underfloor Heating Forum area at

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  1. Kippy-Ken

    Kippy-Ken New Member

    Hi Guys,

    I hope some one can help.

    We have a simple 2 circuit water UFH upstairs in our flat one circuit for each bedroom.

    The Master bedroom heats but the spare is stone cold. The Actuators seem to be operating and the valves opening.

    Below is a picture of the valves. Please ignore the right hand one as that is spare.

    Middle one is to the Master bedroom. Left hand to the spare room that isn't working.

    Only difference I can see is that the left hand one doesn't seem to have the 'float' in the valve.

    Does this indicate what the problem is? Is it and air block?

    If it does and or is, how do I fix it or so I need some help?

    Thanks in advance for any help.



  2. Ch4 plumbing

    Ch4 plumbing Plumber GSR

    Take the actuator head off and make sure the pin rises up, also you can wind the flow restrictor open more with a radiator key, if you only have 2 zones then I would open it all the way up and see if that helps.

    Remember how many turns it took to open and then screw it back to its original position.
  3. Kippy-Ken

    Kippy-Ken New Member

    Hi Ch4,

    Thanks for the reply.

    I took the actuator off and the pin was sticking out by about a centimetre, so I assume that is OK.

    Which valve on the manifold is the flow restrictor? Picture below of the manifold.



  4. Chalked

    Chalked Plumber GSR

    Try turning the flow off. ( red valve) see if the flow meters pop up. If they don't, they might be stuck.
    To fix , turn both valves off and remove the restrictors. Clean then and refit.
  5. Kippy-Ken

    Kippy-Ken New Member

    Hi Chalked,

    Both valves popped up but circuit 1 valve still has no water in it.


  6. Chalked

    Chalked Plumber GSR

    Is the manifold warm? Look like your getting circulation. Also check the water thermostat. Should be about 45 degrees. Try turning it fully clockwise then back to 45. Pipe with red lever should feel warm.
  7. Kippy-Ken

    Kippy-Ken New Member

    Hi Chalked,

    Bottom of the manifold is hot, top half cooler.

    Are you suggesting the water thermostat on the boiler?

    Is the red lever you talk about one of the two shown in the picture on the left? If it is, one pipe with the red lever is hot the other one is cold.

    Could it be a thermostat or controller problem?


  8. Chalked

    Chalked Plumber GSR

    The thermostat girl the manifold is the white knob above the pump. On polypipe systems ( yours) they tend to jam. So fully opening and closing, you should be able to feel the water temperature rise or fall. Depending on what number you set it on. If you can't feel any difference, a new cartridge may be needed.
  9. Kippy-Ken

    Kippy-Ken New Member


    It appears to be working and I can hear it opening and closing.

    If it was jammed wouldn't both circuits not be working? Only circuit 1 is not getting hot.

    Circuit 1 was working so could an air blockage have formed somehow?

    Could there be a fault on the controller that is stopping something from opening (or closing) properly?


  10. Kippy-Ken

    Kippy-Ken New Member

    Hi Chalked,

    I have had someone in to look at the system and now the working circuit has reversed somehow but the state of the flow valves remains the same.

    They are suggesting it is a an air blockage somewhere and they need to drain the whole system and refill it. Cost £250.

    I'm not convinced this is needed, or if the cost is fair.

    Your thoughts would be appreciated.


  11. Chalked

    Chalked Plumber GSR

    They can't drain the underfloor pipework. It does sound like an air lock.
    They will need to fill the loops properly from a hose connected to the water main. The job sould take an hour or so. Try a local plumbing company, who install underfloor,not a call out guy.

    Or have a go yourself. If you look online there will be a video of how to do it.
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