Worcester Oil Boiler Burner Lockout?

Check following:
Defective spark generator.....it has 2 x thick leads, which go into the nozzle area. You will need a replacement part to confirm .....replace and test for correct start up. If this defective, there will be no spark at all. Remove the burner and run a test, pointing the burner safely away from any people. Look down the blast tube and check if the electrodes are sparking.
Defective light sensing diode...again, you will need a replacement to confirm. If this faulty, the burner will fire up, for an instant, then stop.

david
January 2011