I can only get c. heating, no hot water when the ntc sensor wire is disconnected. I have replaced the water diverter valve - micro switch and the control pcb. I have checked that the gas differential valve, dc solenoid valve work only when the ntc wire disconnected. I have earthed the ntc wire and the boiler stops firing. I have noticed the flow switch valve does not move at all. Do you think this is the problem ?

Brandy, November 2011