It's been on the way out for some time. The fan relay or some circuitry driving the relay is failing. I have now wedged the fan relay open so it runs all the time. If I don't do this I get some major arcing (buzzing) between the relay contacts which last a few minutes before melting.
The fan runs all day to allow HW/CH and I switch the boiler mains off last thing at night and back on again in the morning to avoid burning out the fan motor. Embarrasingly, I've been doing this since Christmas.
At some time, I have re soldered dry joints on the board too so its probably about time I replaced it?
Thanks. Have fitted new PCB and a its fixed the fan issues. There is a pot on the board for CH burner pressure which was set half way. The instructions says default should be max. The burners wont light if its not on max and even when its on max there is an alarming delay of 30 seconds or more after the gas valve light is on before the burners light - especially when it hasen't been on over night - this is using CH demand. The pilot light seems ok but has been known to go out over night with the boiler switched off. This issue was present before the new PCB but possibly not so noticeable.
I'll get the boiler serviced soon but want my eyes open to the possible fault.
The delayed ignition might be due to poor spreading across the burner strips cheap nasty boilers are diabolic for such design issues.
There is no ignition pressure adjuystment pot on the pcb. It probably lights for central heating on minimum pressure. When your competent person comes they would need to clean pilot jet, disassemble the burner aray thoroughly clean the jets and the venturi/burner assemblies, probably best cleaned under the tap, jets best cleaned with ultrasonic cleaner.
They would make sure minimum and maximum bp is perfect for G20 3mb and 15mb.
then it should be quite possible to range rate the CH using P1 where minimum is 12kw at 3mb maximum is 28kw at 15mb.
Most houses in the UK 12kw is adequate, 18kw still reasonable, greater; wasteful.
Range rating and ignition failure ought not to be related.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local