Pump live query Worcester Bosch 24Ri

Discussion in 'Plumbers' Talk' started by BHW, Aug 25, 2018.

  1. BHW

    BHW New Member

    Evening all.
    I have a query I'm hoping someone can help me with.
    I have just had an extension built and have wet underfloor heating and radiators in rest of house .
    There is only one pump live from the boiler . Problem I have is whichever source of Heating is selected both pumps come on .
    Anyone any idea how to wire this up
    So I can have either under floor heating or radiator pump on individually ??
     
  2. kiaora

    kiaora Well-Known Member

    Hi
    , you need to zone the two circuits,
    Using two port 5 wire valves
    Underfloor stat energises valve brown wire, orange wire fires boiler.

    Or house stat calls, and the other zone valve fires the orange wire!

    Hope that’s clear
    Regards
    Peter
     
  3. BHW

    BHW New Member

    Thanks for reply , I have 3 zone valves . One for heating (rads) , one for unvented cylinder and one for underfloor . Whichever one fires boiler up the boiler turns pump on ( or both pumps) . I'm just looking for a way to be able to turn the pumps on individually and not both at the same time which happens now
     
    Last edited: Aug 25, 2018
  4. Magicspark

    Magicspark Active Member

    Your boiler has pump over run...Its working as it should. If the Rads or HW are calling then only the primary pump should run and when the rads or HW are not calling then the primary pump will stop after excess heat has been dissipated from the heat exchanger. When the UFH is calling then the primary pump should run and also the UFH pump. When the UFH stops calling the UFH pump should stop but due to the boilers pump over run feature the primary pump will carry on running for a little while to dissipate the heat within the boiler. If you didn’t have the pump over run the heat exchanger will fail. You would also invalid any manufacturers warranty you have on the boiler. What is your reason for wanting to seperate the two pumps, even though they are working as they should?
     
  5. BHW

    BHW New Member

    There is no primary pump . I have the rad/cyl pump and the pump for UFH . It isn't a system boiler . The manifold is under the boiler . The reason for separating is I only want one pump on at a time.
     
  6. Magicspark

    Magicspark Active Member

    Ok by primary pump I mean the one external to the boiler but not the UFH one. I know the boiler is not a system boiler....It’s complete madness that you want to separate both pumps as that’s how it’s intended to work. A couple of relays/time delay relays could achieve what you want.....or change your boiler for one that doesn’t require pump overrun and you could control the pumps from the valves rather than the boiler.....Will probably invalidate any warranty you have.....Crazy
     
    Last edited: Aug 26, 2018
  7. kiaora

    kiaora Well-Known Member

    Hi
    Not seeing your system, it’s difficult to advise, if you can provide a schematic drawing, I’m sure there are plenty of people that can tell you how to wire it.

    If you can run the ufh using only the ufh pump, it’s not piped up correctly.

    Regards
    Peter
     
    Lectrician likes this.
  8. BHW

    BHW New Member

    Thanks for answers even the not so helpful ones . All sorted and running fine now
     
  9. Magicspark

    Magicspark Active Member

    What did you do in the end?
     
  10. BHW

    BHW New Member

    Time delay relays work a treat thanks
     
  11. Lectrician

    Lectrician Screwfix Select

    I think you may believe it is working correctly, but it doesn't sound right. Not just to one person, everyone has the same opinion. Does that not perhaps make you question? Can you not draw a schematic of the plumbing? You will get HELPFUL replies. Every reply in this thread and the other have been helpful. Not one person has not been helpful.
     
    Magicspark likes this.

Share This Page