it sounds like an ignition problem, have you had it cleaned recently?
Andrew, if there was a problem with the ignition then why would it work when the control knob is turned to zero then up again?
It means it gets another 3 attempts at lighting
Can you hear it actually trying to light?
Do you get the green flame light illuminated if it fails to light?
I hear the pump come on but that's all. The power light and the lockout light both illuminate.
Does the lockout light go out when you press the reset and then come on again once it has tried to light?
When the control knob is turned to zero and then back, the boiler comes on and operates normally. The lock out lights goes off. The boiler works fine until its off for a period of time; ie overnight, then will not go on and goes into lock out.
It could be just dirty electrodes preventing it from lighting the first time
When was the last time it was cleaned and serviced?
It was serviced last year so I don't think that's the problem. Whatever the issue is, the action of resetting it after lock out appears to clear the problem.
I suppose it depends whether it was stripped down and serviced correctly?
Are you able to take the front cover and off and check to see it is lights correctly but doesn't know its lit?
Yes have taken cover off and no its not lit.