The central heating works fine on my boiler but does'nt fire up on turning the tap for hot water.
Iv'e changed the thermistor for DHW but it made no difference. The pin in [I think the flow control unit] does'nt travel far enough to operate the micro switch,does this mean the flow control needs replacing? sometimes it does transfere the light to the DHW light and then heats up the radiators and then there is hot water if the rads are very hot.

bill d, April 2010

I cheated and added a small tube to the flow switch which activates the micro switch, then I can get hot water but only after the rads have warmed up enough to turn off the boiler and then the boiler will fire up and the DWH light will light up Fine, but it will be a bit hot in the summer. I think its back to the flow switch, expensive!

bill d, May 2010

This will sound really obvious but.... have you tried moving the microswitch so that when the pin DOES move it is enough to activate the DHW? The microswithes are usually adjustable via a small screw in their middle.

Philbee, April 2010