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Discuss Reverse circulation new build in the Central Heating Forum area at UKPlumbersForums.co.uk.

  1. Jeff

    Jeff New Member

    Hi all,

    Sorry for the delay in responding. The plumber has now run a second return so the upstairs and downstairs returns now have there own returns and these then combine together to go back to the boiler. However the problem persists with the upstairs still heating up via returns when downstairs heating is on. I’m not sure if he had a clue what the issue is. He’s also altered the pipe work around the boiler, bit to no avail.
     
  2. fixitflav

    fixitflav Member

    I still think we need a schematic of the complete system, to check that it isn't piped (wrongly) as my #36. But that might not be easy to do, if the pipes and connection points are mostly out of sight. I suppose the house is complete and habitable, floorboards down etc? It would be good if installers did as-built drawings, but I don't suppose most of them do.
     
    • Agree Agree x 1
  3. Jeff

    Jeff New Member

    Does everyone think the pipes follow the 3 t rule? He moved where some of the pipes joined.

    thumb_IMG_8983_1024.jpg
     
    • Disagree Disagree x 1
  4. Jeff

    Jeff New Member

    Sorry I meant to say he moved the pipe under boiler its the last t on the return now. I think its the Bypass but not sure.
     
  5. fixitflav

    fixitflav Member

    Excuse my ignorance, but what is the 3 t rule?
    It depends where they were moved from and to. As I said before, the problem might be remote from the boiler and cylinder. The system might be piped as in my sketch in #36.
     
  6. Gasmk1

    Gasmk1 GSR

    should there not be a non return valve on the return as the return from cylinder where it tees in could go either way. just a thought
     
  7. fixitflav

    fixitflav Member

    The more common problem, rads getting on when HW called, due to rads returns not all being commoned before the cylinder return joins, has been avoided.
    But you could still have the problem you describe if it's piped as my #36. If the zone valve feeding the top rads is closed, the other one open, the top rads will get warm, I showed the flow path. It only happens because you have zone valves. If just one auto valve fed all the rads, with TRVs to control temperature in different areas, it wouldn't happen.
     
  8. Best

    Best Trusted Plumber

    Just had my first look at the photo of the updated pipework. I can't see anything major now wrong with the heating system pipes.
    The cylinder tee in last on return, as you would expect.
    (There can be some heat gravitating on a return where it keeps rising, like in the photo, if it has a path)
    Only thing I can think of is there are more than one main tee off to a zone causing a loop going to the On zone.
    But I need to think on it sometime I get time
     
  9. fixitflav

    fixitflav Member

    No, it would only do that if the rads returns were not commoned before cylinder return comes in.