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 ??
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
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
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?
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.
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
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
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.