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Discuss One radiator will not stay hot in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. Jason Hill

    Jason Hill New Member

    My living room radiator is cold when all the other radiators are firing. I have checked all the internet YouTube advice feeds. The trv is working correctly, the lockshield valve is also working and I have taken the radiator off and flushed it through and have bled it. I believe it is the furthest from my combi boiler. I have turned all my other radiators off and this makes the living room radiator work, but as soon as I turn one other radiator on the living room one goes back to cold. Any further DIY advice would be much appreciated. Thanks Jason
     
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

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  3. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Just follow croppies thread he coverd it very well cheers kop.
     
  4. Jason Hill

    Jason Hill New Member

    Thanks for your advice. I followed it to the letter. As I got to the living room radiator last and fully opened the valves it still does not heat? Any further advice would be much appreciated. Thanks Jason
     
  5. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Possibly a tired pump pal
     
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  6. snowhead

    snowhead Well-Known Member

    How many radiators in total and what size is the boiler and how old is it?
     
  7. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Uprate the pump to a Dab Evosta pump mate i get mine from plumbcity under a £100 that will shove it round . cheers kop
     
  8. Last Plumber

    Last Plumber Plumber GSR Top Contributor!!

    Sounds like undersized pipework.

    What size is the pipework to the rad? is it the same as the pipework to the other rads?
     
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  9. Jason Hill

    Jason Hill New Member

    Thanks for all your replies. To answer all of them, 10 radiators, the boiler is a main combi eco 30 GC number 47_467_03 , installed in 2008. The pipework is 15 mm to all the radiators. If you all agree it probably needs a new pump then I'll get a plumber to sort it. Thanks Jason
     
  10. steadyon

    steadyon Active Member

    If the pipework to all radiators is 15mm I would suspect that is the problem. However, you may mean the pipework visible (e.g. floor to radiator) at each radiator is 15mm. If this is the case, it may be there is a "backbone" of 22mm (or larger) flow and return pipes, with a "tee" off to each radiator. If accessible, look under the living room floor boards and see if the pipework is 15 or 22mm

    If however the problem radiator has been added to the system and is connected to another radiator by 15mm pipes, that could be the problem, as could a radiator being added before the problem one and bridged across the original 15mm pipes.

    Replacing the pump might do the trick, but I don't think anyone could guarantee it.

    Is the problem radiator a standard type, or is it a vertical "designer" type?
     
  11. Last Plumber

    Last Plumber Plumber GSR Top Contributor!!

    I think you need a Heating Engineer to assess the pipe work and rad sizes before you do anything.
    I wouldn't personally 'try' changing the pump because it won't be cheap and it may not be necessary.
    Different sizes of pipe deliver different flow rates per hour. It is possible that 15mm is undersized and that would give the symptoms you describe.
     
  12. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Has this just happened ,did you inherit the system , did it work correctly before ?
     
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  13. Jason Hill

    Jason Hill New Member

    Thanks once again for all your replies. To answer each query, the entire system was a brand new install in 2005 with all brand new pipe work being above ground. The pipe work from the boiler is 22 mm but it all becomes 15 mm as it feeds into the radiators. All exposed pipe work is 15 mm and the living room one is fed by 15 mm pipes from other rads. All the rads are original standard type from the install in 2005. The problem has not always existed. Is it time to call out a heating engineer. Thanks again, Jason
     
  14. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    If it worked ok from day one , it cant be pipe sizing , gut instinct as I have said earlier is probably the pump , we have a way of testing them lol , but I wont tell you how , please report back on any findings.
     
  15. Jason Hill

    Jason Hill New Member

    Thanks for all your advice. I will update the thread when I have got an engineer out. Jason
     
  16. dan_the_plumber

    dan_the_plumber GSR

    Have you had your system converted? Probably from a back boiler to a combi? Or from a boiler in one part of the house and your new boiler re-sited?
    Sometimes plumbers connect into the 15mm branch, instead of connecting back into the 22mm 'source' pipework.
    This can result in balancing issues too bad to 'fine tune' by adjudting radiator valves alone.
     
  17. Jason Hill

    Jason Hill New Member

    As previously mentioned the whole system was newly fitted in 2005. There have been no further updates or additions since then apart from the current boiler being fitted in 2008. Thanks for your question. I'm still waiting to get hold of an engineer. Thanks Jason
     
  18. Dkdc71

    Dkdc71 Member

    Try and remove the trv head and see does it make a difference they can play up sometimes as someone previously said if it worked from day one it's a process of elimination good luck with it
     
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