As you don't asy which make or model boiler you have, or whether you are reseting the Oil Burner or Overheat stat, I can only give very general advice.
if Sealed System - is pressure (Cold) correct?
Is Boiler control thermostat turned up to Max (this could be too high)
If Burner Lock out Could be Motor Capacitor faulty
I would suggest as its autumn it would be a good time to get the boiler serviced & checked out
www.elanar.co.uk, October 2009
