Megaflow Probs

Discussion in 'Plumbers' Talk' started by Stitch Jones, Jun 6, 2008.

  1. Stitch Jones

    Stitch Jones New Member

    A friend of mine has called me with probs since his megaflow has been plumbed in. System as follows.

    Y-Plan

    Megaflow with additional 2-port to comply to regs

    Vented heating circuit.

    Problem is HW side.

    Once system is calling for HW only, when HW reaches temp the 2-port closes but system keeps on running & causes pumpover on F&E tank & them overheats.

    Electrician has checked wiring all OK

    Anybody else suffering same prob/any ideas?.

    Stitch
     
  2. Captain Leaky

    Captain Leaky New Member

    If it's just been plumbed in get the plumber back pronto!
     
  3. Stitch Jones

    Stitch Jones New Member

    2 Years ago, Plumber does not want to know.

    Could it be a prob with 3-port not working correctly?.
     
  4. Captain Leaky

    Captain Leaky New Member

    it is quite likely but I thought the spark had checked the electrics?

    Get a decent plumber in!
     
  5. Onetap

    Onetap Member

    Y-plan uses a 3-port mid-position valve. You can't use a 3-port on it's own, because the DHWS port is open when the power is off. So he has added the 2-port zone valve to the pipewrok on the DHWS outlet port of the 3-port valve.

    I'd think he had just made a hash of the wiring.
    The Honeywell wiring diagrams are here,

    http://content.honeywell.com/uk/homes/systems.htm

    but you'd need to work out how the additional wiring should be added to the existing 3-port wiring actuator.
    It would be a more sensible idea to change it to S-plan wiring (two 2-port valves).
    It's more reliable than mid-position valves and the nest person to work on it will be able to find a standard wiring diagram.
     
  6. Onetap

    Onetap Member

    2 Years ago, Plumber does not want to know.

    Did it ever work properly, or is this a recent defect?
     
  7. Captain Leaky

    Captain Leaky New Member

    It does read that it has never worked, get a different plumber or electrician in. I agree with 1t it sound suspect.
     
  8. bettyswallocks

    bettyswallocks New Member

    sounds like there is no bypass fitted and its pumping over and over heating on pump over run.
     
  9. Its a simple wiring modification needed.

    In words a competent person would just wire the switch in the two port in series with the HW switch in the three port to end the call for heat.

    Thats the simple modification to make it work!

    Tony
     
  10. bettyswallocks

    bettyswallocks New Member

    so what happens when the two port closes?, the heat from the pump over run has to go somewhere, it cant go to the ch because the 3 port is closed, the pump is just running against a closed circuit, it needs a bypass
     
  11. Mr Ian

    Mr Ian New Member

    I concur. Bad design, get the plumber back.
     
  12. rome60

    rome60 New Member

    SJ,I cannot understand why plumbers go for a Y plan on unvented systems,it is not recommended.Replace the mid position valve & convert to S plan,there is only a small alteration to do on the wiring up.Have you checked the the wiring from the two port valve back to the electric control box where the thermastat is.It is obviously a electrical fault along with a bad plumbing installation;(
     
  13. Captain Leaky

    Captain Leaky New Member

    Don't get the same plumber/sparky back, they don't know what they are doing!
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice