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Discuss Unvented wiring . in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Strange request for Easter Sunday lol , its just in my head .
    have any of you fine chaps got a wiring diagram for a y-plan with a new 2 port wired in for an upcoming unvented installation.
    I usually change them to an s-plan but the boiler is miles away from the cylinder and would cause a load of work getting perm lives to the 2 ports .
    Cheers in advance
     
  2. EvilDrPorkChop

    EvilDrPorkChop GSR

    Creates more hassle than it's worth IMO. Have you checked the wiring, you usually have enough wires to do it anyway, especially if theres already a pump overrun.
     
  3. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    Can you add a 2 port to a y plan? With the 3 port keeping one zone permanently open, what happens when the 2 port calls for heat? You'll get unwanted heating of a zone.
     
    • Like Like x 1
  4. EvilDrPorkChop

    EvilDrPorkChop GSR

    Yes you can. It's on the HW side, so you can leave your 3 port in situ and have the 2 port for thermal cut out for the Unvented after the 3 port valve. It's doable but for everyone that i've come across it's not worth the hassle and easier just sticking two 2 port valves in.
     
    • Agree Agree x 1
    • Informative Informative x 1
  5. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    Ok, I get what your saying, but if the 2 port acts only as a thermal cut out, what happens when the cylinder stat on the first cylinder is satisfied but the thermostat on the second isn't? You could end up with unbalanced temperatures.
     
  6. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Ancient boiler pal , so no spare wires but just realised there must be a hw off wire , but really need 2
     
  7. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!


    I have never done it but a 2 port should be fitted on to a y plan unvented installation, yes a right pita
     
  8. EvilDrPorkChop

    EvilDrPorkChop GSR

    If you've got a HW off wire then you're sorted. Change that for a perm live, you'll already have Neutral and Earth there, along with HW on and CH on.

    It's when you haven't got a HW off wire that's the issue (So when they have to have HW and CH at the same time)
     
  9. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    So your not having 2 cylinders? Why do you have to a 2 port on a yplan when feeding an unvented?
     
  10. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    I have not looked , I just thought of it as I was typing
     
  11. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    In case it goes *** up , spring return valve closes supply to cylinder
     
    • Like Like x 2
  12. EvilDrPorkChop

    EvilDrPorkChop GSR

    Part of the G3 regulations. Must have a thermal cut out, as a 3 port valve is always open in some form that doesn't meet the requirement.

    See so many Unvented cylinders on 3 port valves, it's worrying! Had one where the High limit stat kept cutting out, so cylinder must have been about 85/90oc!
     
    • Agree Agree x 1
    • Informative Informative x 1
  13. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Wheres yer GS badge ??? Admin still in the boozer
     
    • Funny Funny x 1
  14. EvilDrPorkChop

    EvilDrPorkChop GSR

    Must be! :D
     
    • Funny Funny x 1
  15. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    Good to know, I suppose if I had my g3 I would have known that :rolleyes:
     
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