C Plan

[JohnD]

The Drayton 2-port 28mm normally-closed spring return valve (which I understand is the correct one to use on Gravity HW) ZA6/779-2 has 6 wires - orange, blue, brown, white, grey, and a green/yellow wire (that's 5 plus earth)

I happen to know because I have just got one to put on my old mum's 28mm gravity HW.

I haven't got the circuit digram about me just now, but I've got it somewhere. Drayton sent me one on request (but do not include it with their usual publications as I understand it does not conform to current building regs (I'm guessing because it is not fully pumped).

looking at their datasheet, it says the 22mm 2-port zone valve only has 5 wires. I don't understand why

 

[uselessFCUK]

See

http://www.diynot.com/forums/viewtopic.php?t=140857

 

[JohnD]

thanks, I hadn't seen that (my mum currently has an old Cyltrol which appears to be stuck open, possibly badly adjusted but now won't move)