Works fine on HW but no CH. When called for boiler fires up with C on display but then flame goes out. Any ideas? Thermostat fine. Would it do this if diverter valve was passing?
OP, I get the feeling this is NOT a combi boiler.
Do the water pipes come out of the top of the boiler, or the bottom.
What does it say on the front cover....HEAT, SYSTEM, or COMBI?
Do you have a hot water cylinder?
It certainly does appear to be a flow related problem....
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