by htg engineer »
Sun Sep 16, 2007 6:55 pm
Could be a few problems
diverter valve stuck
diverter diaphragm split or stretched
faulty microswitch
Without knowing what you're doing, you'll struggle to diagnose the fault yourself. Call a heating engineer to take a look.
My guess would be the diaphragm in the pressure differential valve has split. If you know what / where on the boiler this is, you may be able to do some more checks. Let me know.
if i can help anymore i will