Central Heating query

[NG1965]

Hi, I've was called to look at a heating system that the plumber believes has a wiring fault. Everything works electrically and looking at the diagrams is all connected as per ..... however when the cylinder stat reaches temperature, the system stops pumping round the radiators. If you turn up the stat off the pump trundles (the wiring matches the diagrams). The central heating programmer continues to be on ie the lights say all is well. All of the controls are Danfoss with their wiring centre.

Any thoughts, ideas or pointers would be appreciated. Thanks. Neil

 

[stuart569]

Must have the switch wires for the heating and dhw mixed up.Take it its a y plan?

 

[NG1965]

I believe it is a Y plan, switch wires would make sense now! Doh! The whole lot was wired in 3Core and eth with no markings to say what does what, even an earth has been used. Cheers