In such a situation, restarting after refilling the oil supply might require some tools and expertise, especially with a one-line oil supply. Delivery drivers often can and will do this.

I can understand your wanting to help as perhaps with all the combos the tech may not have the correct nozzle with him. At the same time if you have chosen a good service co that sent a quality tech for other reasons such as wanting to install an 80 degree instead of a 90 because it was impinging on the side of the target wall or because oil boilers are sold by # of sections that can take several different nozzles. He or she may have chosen one that wont short cycle the burner, based on your system. Sometimes even the manufacturer may state to use a hollow however the boiler will rumble and a semi-solid clears that up. My answer, I should clarify is to put your trust into the tech, however question perhaps why they used the nozzle they did.

Good point baymee, I'll have to contemplate that one but also check to see if the draft is in fact adjusted correctly. Mark, thanx for that chart, thats really helpfull, I'm printing that as we speak. You work in a northern climate too as I recall. You probably see the same thing all the time too, people blocking off their combustion air vents because of the cold air coming in and the fear of freezing pipes. Thats why I think the "fan in a can" is such a good idea. We seemed to have comandeered this "Beckett burner won't stay running" post, but I believe we've all told him all he has to know to make a decision on what to do.

Boiler is a Burnham RS109. It was serviced late fall, no issues noted. It had been working without issues until yesterday morning. We noticed there was no heat. The blower was on (vented thru wall), but there was no flame. We pressed the relay button and it turned on and stayed on, but last night it happened again. The thermostat call for heat, the blower starts but there's no flame until we press the relay. It doesn't turn off after a while so apparently is no a cad cell issue. It stays on until it reaches the temp the thermostat is calling for. But apparently after some hours, it's unable to turn on automatically as needed. What could be wrong? We checked the cad cell, the electrodes, the motor and oil pump. Could it be the relay? Thanks!