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Discuss One of Downstairs Radiators does not heat up! in the Central Heating Forum area at UKPlumbersForums.co.uk.

  1. Fredy

    Fredy New Member

    I C.H. system with a combi boiler. 4 rads on 1st floor,1 in the attic and 2 on ground floor heat up perfectly but 1 of 3 rads on the ground floor does not heat up. It gets warm across the upper 1/3 part after at least about an hour. 22mm return and flow pipes feed all of the mentioned radiators via 22mm x 10mm (metallic bronze) manifolds on first and ground floor. Hot water from the boiler gets to one side of the rad but does not flow back to the return pipe through it. I have done the following work to resolve the problem without any joy.
    1. TRV & lockshield valves checked - found functional not seized,
    2. suspected blockage in the radiator, return pipe to the manifold - rad
    flushed and pipe checked but there was neither blockage in the rad nor
    any sign of restriction in either pipe or in manifold - rad still cold,
    3. air lock in the pipes and the the rad in question checked,
    4. pump is checked, the whole system balanced, all of the upper floors
    rads turned off - pump found running fine and no difference observed on the ground floor rads,
    5. turned off all of the rads including ground floors except the one in
    the question - No Joy! A mystery.
    6. coupled TRV and lockshield valves using a 15mm pipe - Hot water
    from flow side flows to the manifold at the return pipe.
    I am planning to change replace 22mm x 10mm manifold to 22mm x 15mm manifold. Boiler is situated in the kitchen on ground floor. The above mentioned mysterious rad is in the living room i.e. nearest to the boiler. It is very mysterious problem. Any advice / suggestion from fellow forum members would be appreciated.
     
  2. Rob Foster

    Rob Foster Top Contributor!!

    This is a very good post, you have covered most of the bases. I think that this rad may be piped up wrong ie rtn to rtn or feed to feed so it’s only getting passing flow. It’s a good one and let us know how you get on
     
  3. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    Has it ever worked properly and did you say that it worked properly when you piped the trv and rad valve together or not?
     
  4. Fredy

    Fredy New Member

    Thanks Rob for your comments. It is connected properly i.e. flow to TRV and return to the other side. It is beyond my understanding. I have used all of my theoretical knowledge and practical/observatory skill to eradicate any possible fault. Therefore I have named it “Mystery”
     
  5. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    Has it ever worked properly
     
  6. Fredy

    Fredy New Member

    Hello Harvest Thanks for your interest.
    I purchesed this house recently. This problem existed as the C.H. turned on. There was a very long over 2000mm x 600mm double rad was fitted originally. It covered almost one of longitudinal wall of the room. I intended to replace it with a smaller one even it would have n’t any problem. The original rad was checked and flushed as described in my previous post.
    The rad in question is connected to the same flow and return manifolds where the other 2 perfectly working rads are connected.
     
  7. Fredy

    Fredy New Member

    Hi Harvest, The hit water circulated from TRV to lock shield valve to Return manifold through 15mm pipe. I eliminated the rad by removing it.
     
  8. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    Surely this a rad issue then if when it was bridged it worked properly
     
    • Like Like x 1
  9. Rob Foster

    Rob Foster Top Contributor!!

    Simple maybe is the trv jammed down take head off and give the pin a sharp wack with a ball peen hammer
     
  10. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Rule the rad out 100% by taking it off and just put a piece of copper inbetween the two valves and see if you get circulation.
     
  11. Fredy

    Fredy New Member

    The TRV is neither jammed nor sticking. Pin moves smoothly with a minimum pressure. I have got a new TRV when I replaced the rad. The old TRV was also not stuck in closed position.
    Hi Townfanjon
    Yes I have coupled both valves with a 15mm pipe. The water flew through satisfactorily. After this test I concluded a “Defective” radiator and replaced it with a new rad with new valves but the problem remained unresolved!
     
  12. Rob Foster

    Rob Foster Top Contributor!!

    where are you ? if u are less than 20 mins off m5 junctions 1-6 m6 21 -8 - m1 south of catford interchange (a14) to london then AND NOT FRIDAY AS ITS POETS DAY MAKE a brew and who knows we could darken your door -- southbound 0700am northbound whenever - we still (yawn) are men in vans. not me they are but i could tag along get dropped off and they would gey me on way back from where ever your call CHKing
     
  13. Fredy

    Fredy New Member

    Thanks mate for an offer but I am over 100 miles to north of the country.
     
  14. Best

    Best Trusted Plumber Top Contributor!!

    You might be getting very slow flow through the pipes.
    You say when you opened valves - water flowed ok, and when you joined the valves with a piece of pipe then the pipe heated from flow to return.
    But this could indicate a faulty rad valve on the return. The works of the valve might be pushing down when flow goes towards return, perhaps almost tightly off.
    I have seen this only occasionally. Worth a try
     
    • Like Like x 1
  15. Fredy

    Fredy New Member

    Yes water travelled from TRV to LSV via 15 mm bridging pipe instantly.
    Your observation does make sense but it confuses me to question
    Thank you for your reply and I appreciate your contribution in order to help me. It does make sense what you say but I am confused why did both valves work when linked up by a 15 mm pipe? Please note that the both valves are connected to flow and return 22mm pipes with the 10mm pipes.
    As you said worth trying. Although both valves are new but there might be unexpected defect present causing the problem. I am intending to feed the rad using 15 mm tube and at the same time I will check the valves too and I will keep you posted
     
    • Like Like x 1
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