Thanks for all your replies and concern for my welfare. I have done several repairs on this boiler(replacing diverter and installing ex. vessel on return pipe as original in boiler broken), none of which involved the gas side. I also guess that my problem is not gas related so was hoping for advice.
When hot tap is open, the burner fires up for a few secs,then cuts out. It keeps cycling like this – on/off/on/off. The primary pipesfrom main hex to plate hex are extremely hot, as is the plate hex itself.However, the hot pipe to hot taps is barely warm.
As the primaries are very hot, I’m presuming that the hw ntc is OK – though if anyone could tell me how to test it’s resistance, I would be grateful. I’m leaning towards the plate hex, especially as it’s a hard water area. Do plate hexs suffer from scaling in hard water area? Would this cause my symptoms? How can I confirm whether or not it’s the plate?
Thanks in advance to anyone who can help. I’m not looking for gas-related advice, and would not go anywhere near the gas components of my boiler
