H'i Terry,
The problem with your boiler is the domestic hot water diaphram. This is fitted as part of the diverter valve, but you can purchase seperatly.
After a period of time they become perforated, and concequently dosen't lift the push rod, which operates a microswitch, which in turn operates the boiler in D.H.W mode only.
When your boiler is in HEATING & D.H.W mode, with your room stat calling for heat, you will probable get a limited amount of hot water, also it won't be as hot as normal because the burner flame will be at a lower pressure than when the system is in D.H.W mode, and working properly.
You should pay around £15-£20 for a diaphram kit. Good luck!
Dave.
Dave Williams., February 2006
