Hello
My trusty Vaillant 242 EH is having some issues.
It has developed an issue when firing up the burner. The fault is seen with the hot water and central heating.
When it operates it takes anything from one to several attempts to light and when it takes too many the lockout circuit is tripped.
Each time it tries to light it does light the burner and then the flame goes out immediately and then it ignites again this repeats until it works or trips. Once it stays lit it is fine while there is a demand.
I've given the combustion chamber a service and checked the DHW and CH overheat sensors as well as the NTC resistor.
Measuring the voltage at the gas operator shows 20v when operating. It also shows 20v when the fault shows and cycles between 0 to 20v each time it tries to fire up. I'm not sure if this is the fault or normal operation.
I tried changing the Flame supervision, Thermostat and Fan circuit PCB's with spares which made no difference. The only other board that I don't have is the main switch one that the others plug into. I'm also wondering if the transformer is failing and dropping the 20v due to the extra load powering the ignition spark.
Any help would be appreciated.
My trusty Vaillant 242 EH is having some issues.
It has developed an issue when firing up the burner. The fault is seen with the hot water and central heating.
When it operates it takes anything from one to several attempts to light and when it takes too many the lockout circuit is tripped.
Each time it tries to light it does light the burner and then the flame goes out immediately and then it ignites again this repeats until it works or trips. Once it stays lit it is fine while there is a demand.
I've given the combustion chamber a service and checked the DHW and CH overheat sensors as well as the NTC resistor.
Measuring the voltage at the gas operator shows 20v when operating. It also shows 20v when the fault shows and cycles between 0 to 20v each time it tries to fire up. I'm not sure if this is the fault or normal operation.
I tried changing the Flame supervision, Thermostat and Fan circuit PCB's with spares which made no difference. The only other board that I don't have is the main switch one that the others plug into. I'm also wondering if the transformer is failing and dropping the 20v due to the extra load powering the ignition spark.
Any help would be appreciated.
