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Underfloor heating problem

Discussion in 'Plumbing and Central Heating' started by rb1980, 27 Oct 2015.

  1. rb1980

    rb1980

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    Good morning all. I have a wet UFH system that seems to have stumped 4 plumbers etc.2 of the rooms just don't heat up at all. The other 2 zones do. Have a new pump , the last engineer said wasn't air locked..can adjust flow from 0 to 4 ltr/m but nothing seems to work. Any thoughts / suggestions much appreciated
     
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  3. dilalio

    dilalio

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    Have you tried shutting down all zones except the defective ones?
    Force all flow through each defective zone in turn, using the actuators, and see if the zones heat up!
     
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  4. rb1980

    rb1980

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    g.m sir. I have yes...I also tried to purge that loop of air and when running the water thru got 4 ltr/m flow too...? I have the mixer at 45/50 degrees...
    I have had the cold room running all day with the actuator removed..still nothing.
     
  5. Biggles..

    Biggles..

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    Crossed connections.
     
  6. rb1980

    rb1980

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    all the actuators are controlling the right rooms..if that's what you mean?
     
  7. dilalio

    dilalio

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    Without being there, I would consider...

    • blockages in circuits.
    • manifold problem
    • actuator problem
    • automatic/manual bypass allowing flow to take easiest route!

    As Above... Without being there, it is a bit baffling!
     
  8. sjroberts1

    sjroberts1

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    Has it ever worked in those said rooms?
     
  9. rb1980

    rb1980

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    Morning. Yes they have worked previously. As we're fine when my 1 kid slep there.
     
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  11. rb1980

    rb1980

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    Hi. They have worked before. How would I know if there's a blockage? When I purged that loop the flow showed 4 ltr/m . How do I know if there is some bypass as mentioned above? Room still cold even if only one on
     
  12. rb1980

    rb1980

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    What problems can the manifold have? Not actuator as I have taken them off and let the system run ..
     
  13. dilalio

    dilalio

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    When shutting all other zones down, Can you feel any heat at the flow pipes to the said zones at the manifold location? Can you trace that heat by feeling the floor as you come away from the manifold? Is the system in screed or on insulation between joists on a suspended floor?

    If there is any heat getting through from the motorised valve(?) to the manifold and then into the defective zones, you should be able to touch trace it!
     
  14. rb1980

    rb1980

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    yes the flow pipe to the "cold" room is very hot, the return comes back luke warm , does get a bit hotter when I turn the mixing valve up or the crank the flow right up..
    screed I believe. haven't tried to touch trace the heat.i guess I can try that later. the way the floor and pipes are layed out its possible there might be a small section that goes across the hall and into the room..i don't recall feeling any heat following that path tho. the flow side of the manifold is really hot. the only way to get really warm return is to turn up the flow and the mixing valve wihcih I guess isn't the best idea
     
  15. dilalio

    dilalio

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    Once isolated, any of those UFH zones should fly through and heat should almost be the same at the return, as the flow!

    Try seeing if the 'pins' on the actuators to those zone are sticking! Compare their positions to working zones. Try tapping them down gently and pulling them up. See if they free up and heat starts flowing through the circuit and manifold when other zones are off.

    Maybe a power flush is required otherwise?
     
  16. rb1980

    rb1980

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    the thermometer on the flow shoe anything from 50-60 degress. when I have the mixer valve set to say 45 the temp guage on the return shows 30 ish at say 2 ltr /min. I know the difference should be about 8-10 degrees . the last plumber said he thinks by looking at the water in the flow gauges the power flush prob not needed. is it something I can do my self?
     
  17. dilalio

    dilalio

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    When all else fails a power flush has to be considered!

    Unless there are kinks in the circuit when it was installed or constricted but not pierced by later works that could have affected them... Bottlenecks in the circuit!

    It does seem to lead to crud in the circuit!

    Can you feel heat by laying on the floors or is it just that those rooms feel colder? Are they poorly insulated, large windows? North corner of the house??
     
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