Wiring for Heating - possible mixed circuits

[frediaz]

I have got a heating system with underfloor heating on one floor and radiators on another.

The UFH has its own wiring centre and gets mains power (for the pump, zone valve, etc) from one circuit in the house.

The boiler and related electrics for the c/h and hot water have mains power from another circuit in the house elsewhere.

The thing is, if I connect the boiler interlock wire from the UFH wiring centre to the boiler wiring centre, have I got a problem mixing mains power in 2 different circuits?

The connection at the UFH wiring box is like this:
Zoom in to see the details
View media item 5969

 

[hairyben]

Either run a power supply link so it's all on one spur, or use a relay to seperate the circuits, so the underfloor "call for heat" powers the relay coil, with the boilers "call" triggered on the switch side, electrically seperate

 

[frediaz]

So if I run a power supply link from one to the other, this means that I do not supply power to one of them from the other circuit?

 

[hairyben]

So if I run a power supply link from one to the other, this means that I do not supply power to one of them from the other circuit?

aye, if you do away with one of the spurs so it's all controlled by single fused spur.

 

[Spark123]

It will mean they are both supplied from the same fused spur therefore no issues of having it fed from two separate circuits.