answer this before you commit and be careful, its live in there!!
undo the 2 posi screws and lift off white fascia panel and drop elec tray down on hinge.
when you turn htg on you'll see a pin rise on top of brass assembly and make a microswitch and fire boiler. turn off.
when you get someone to turn on a tap observe what happens. you should see a pin come out the front of the brass assembly aswell as the top pin and make both microswitches. the pin that comes out facing you is the hw demand.
Does it come out? does it hit the microswitch?
iain
November 2008