heating works fine but when you turn hot water tap on the water runs cold ive changed pcb board and flow switch still got no hot water any idea,s thanks

jonathan, February 2009

I think your on track with this one . if heating OK then boiler ignition sequence is fine. The boiler needs to recognise that a tap has been turned on which it does by the water on its journey to the tap flowing through the dhw FLOW SWITCH,( this has a small 24vDC current coming from the PCB waiting at the DHW flow switch to operate the micro-switch with-in it when the water passes through it ). normally 2 purple wires one into the flowswitch the other coming out returning to the board to tell it there is a tap open and that the boiler should fire up.

papmc, February 2009