wiring for new under floor heating system

[457buf]

Hi all,

This my first post, so be gentle with me!!

I have just fitted a reliance one zone UFH kit to my extension, Ive come to wiring it up now. The system boiler is wired directly to the existing C/H pump, so that pump runs as soon as the boiler fires up. What I want to know is when the existing C/H and DHW is off and the new UFH is on and the boiler is running to provide heat to the UFH only, how do I wire system so that the C/H and DHW pump doesnt run??

How it is at the moment would mean that the C/H pump would be trying to pump water past the closed 2 way valves in current system, when UFH heating is running.

Can i wire the C/H DHW pump to the switched outputs of the old room stat and cylinder stat (brown on 2 way valve) to trigger the pump. therefore meaning the pump wont run when just UFH is on???

Cheers Darren

 

[Norcon]

It sounds as though you've connected before the boiler pump in which case you'll probably need relays.

It usual practise to connect after the boiler pump with a by pass fitted. The UFH will have a separate timer, roomstat and zone valve.

 

[457buf]

I have connected the UFH to t pieces directly at the feed/returns at the top of the boiler. It then goes to the zone valve, pump, mixer etc. My original pipe work from boiler to C/H DHW doesn't have a bypass valve fitted. So should I fit one, so the boiler pump can continue to run when UFH is on, or should I just wire boiler pump/UFH pump via a relay of some sort as you said??