Many thanks for the suggestions...
I metered the solenoid, was about 2.7K Ohms
Cleaned the photocell window. I'll get one to try tomorra..any suggestions for suppliers likley to have 1 in stock?
wilhelm...what should I look for in the blast tube as you suggested?
My oil boiler has started locking up.
Boiler fires up and runs for perhaps a minute, then clicking noise and lockup.
Plenty of oil in the supply tank, checked spark OK.
Took oil supply pipe off where it enters the fan housing, plenty of oil came through, no bubbles.
Tried a new...