Radiator not working

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  • zoe's Avatar
    Level 1
    The radiator on the top floor (2nd) of our house isnít heating up at all.


    We've had a few different people out to try and fix the problem over the 18 months and done the following:

    • Cleaned the whole central heating system out followed with an inhibitor (done this multiple times)
    • New TRV installed
    • New radiator installed




    Each time we've done these, the radiator will work for a day or 2, and then stop again.


    The pipe going into the radiator is hot and can be traced along the floor by the warmth right up to the trv valve, but the radiator itself is cold, as is the pipe going out of the radiator.

    The TRV pin isn't jammed and we've bled the radiator. All other radiators in the house heat up perfectly. We had a new boiler installed earlier this year and the system has been great but this one radiator just will not heat up, even if we turn all the others off.


    We've spent quite a bit so far trying to get this sorted and it's frustrating that each time we think it's sorted, it ends up stopping again. Would love any other suggestions that might get this fixed!
  • 10 Replies

  • Mike heat eco's Avatar
    Level 1
    System needs balanceing should have been done at time of flush. Failing that pumps to small
  • RJHeating's Avatar
    Level 1
    Iíd agree, likely a balancing issue if itís all piped in correctly.
  • seastate's Avatar
    What's been said above....

    Easy way to check if it's just balancing is to close of the other radiators and it should heat up
  • Graham the plumber's Avatar
    Level 1
    If the radiator doesnít work with all the others shut down itís not a balancing issue.
    If the pipe up to the valve is getting hot it means there is flow but restricted.
    This means faulty rad valves, blocked pipe or an air lock.
    Is it a pressurised system or gravity fed?
  • Westflow's Avatar
    Level 1
    Is it a one pipe system? I had a radiator not getting hot where the pipework went up, and then back down creating 'heat lock'

    Is the radiator piped up correctly (not both off flow or both off return)?

    I have had it before where we found a valve under the floor almost turned off.

    If you have turned off all the other radiators and is still the same then I don't think it is a balancing situation
  • GatterGas's Avatar
    Level 1
    Have you checked the radiator itself is not blocked ? Or the rad return is restricted. Failing that as others say itís either 1 pipe , balancing ( but then you say with all turned off it doesnít heat) or pump ? But definitely check the radiator isnít blocked inside or blocked rad tails. Manually flush it out with a hose maybe to be sure
  • zoe's Avatar
    Level 1
    We had a new boiler and 2 radiators fitted back in March so the system was balanced then and hasn't been adjusted since.

    Things have changed since I posted. My partner took the TRV valve off in case that was the issue and I turned off all the other radiators in the house. Went up to the one that wasn't working - there was a very slow drip coming out of the bleed valve that couldn't be tightened. We drained the water out but couldn't get the valve shut tight again so we had to leave it until we could get a replacement so it was very slowly dripping water and the pressure obviously kept dropping.

    That night, while I was in the room I could hear hissing coming from the bleed valve. Went over to check it and the radiator was hot!

    I went today and got a replacement bleed valve and fitted it and have kept the TRV off and again, its getting hot - but mainly at the top so still not perfect but at least it's doing something.

    Could it potentially have been an airlock and a faulty TRV?
  • Tye's Avatar
    I think the rad has been piped wrong, either both in the flow or both in the return. Either or it will only heat up gradually the longer itís on but itís not circulating. If it worked properly after it was installed then while you e got the head of the trv try pulling the pin up!
  • zoe's Avatar
    Level 1
    @Tye The pin is up :) It was one of the first things we tried and it moves up and down no problem when pushed. It only ever works for a few days and then stops again...so not holding my breath that it's going to keep heating up beyond the weekend.