i have a ravenheat fanned combi CSI 85 A (T), i have no hot water but i have heating , i have checked and replaced the DHW sensor , checked the plate to plate (not scaled up ), the diverter valve is working switching from water to heating but when you turn the hot water tap on it switches the burner off and dosent ignite , any ideas?

sharron m, September 2009

Diverter Valve Microswitch, is the Diaphragm pushing the pins out far enough?
I would try replacing the Diaphragm.

www.elanar.co.uk, September 2009