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Discuss Radiator heating up-issue in the Plumbing Forum area at

  1. Paul575

    Paul575 New Member

    Hello, I’m after a bit of advice regarding a radiator that warms up but only gets approx 60% as hot when compared to others.

    I live in a small 2 bed property - 6 radiators, 2 bedroom, 1 landing, 1 towel & 2 downstairs.

    The downstairs radiators are back to back on a dividing wall both fed from the same flow and return pipe work (the pencil sized copper pipe work). The radiator on wall where the pipework runs along skirting is nice and hot, this flow and return pipework is “teed” off through the wall and is connected to the rad on the opposite side of the wall. This radiator only gets approx 60% warm when compared to the other. The return pipe on this radiator is only warm to the touch where as the opposing radiators return is hot. My plumber has tried balancing the rads, locking down all the TRV to allow flow to the problem radiator, but nothing seems to improve / increase the temp.

    Could this be an issue with teeing off? In that the water will not flow as easily to the Teed rad. Not sure what else to try to be honest, and it’s typical that this rad is in the room we use the most.

    Both rads are new, with new valves, and fed by a relatively old but reliable combo boiler.

    Anything else i can try?

    Any advice much appreciated
  2. DuncanM

    DuncanM Plumber GSR

    Kink in you microbore (pencil pipe) flow or the return. Lift a couple of boards see what's happening. Also microbore might not do the job if it is plumbed in to microbore. Try and feed pipe back to the manifold.
  3. Paul575

    Paul575 New Member

    I have added a couple of photos where you can see it’s teed off, it’s hot at this t junction, but only just about warm where it comes out of the wall at the other side.


  4. Gasmk1

    Gasmk1 GSR

    the hot rad is taking all of the heat as water will take the easiest route, try turning off the hot rad and see if it gets the cool one hotter if so then you will need to balance the system to make sure you get it to flow properly
  5. Riley

    Riley S. Mod Trusted Plumber GSR Top Contributor!!

    Is this newly plumbed in?
  6. Paul575

    Paul575 New Member

    I have had new rads, trv, etc but to be honest, the rad before had the same issue!
  7. BYP


    Do you have a system filter? Has the system been powerflushed? When you say new do you mean they was an existing rad in the other room before and it’s been replaced or you have had a new rad installed and it’s been tee offed the one in the room next door? Also try what gasmk1 suggested
  8. AWheating

    AWheating Trusted Plumber GSR

    first thing to do is balance the entire heating system
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