Abig oil burner problem

[dogsden]

I am not a plumber but I am posting this topic on behalf of my plumber who is at a loss to know how to solve the problem. I have an Abig Nova Oil burner which he has serviced but there is still a problem. He has replaced the jet, the filter, the capacitor and he has verified that the motor and fan are working correctly, but it still keeps 'tripping out', i.e. the red light comes on and the burner stops working. This sometimes happens after 8 hours, sometimes it can happen every hour or so. He has disconnected the oil inlet and outlet lines and run them from and back into a fuel drum instead of from and to the oil tank, in case there was an air hole, but the problem was still the same which suggests that air intake is not the problem.

Has anybody come across a problem like this? Can anybody advise?

[leaky50]

It could be a bad control box.