Boom! Oil fired

FLGhp22

I’m a contractor I do a tune up every year last 3 yrs on this oil fired boiler. Changed nozzle, strainer, filter. Smoke, combustion, draft test and all were right on when I did it a couple months ago. Got a call from them a couple days ago so I went back cause it would run but every so often it would studder is the best way I can describe it like it’s getting a surge of oil and barometric damper kicks open slightly. Changed nozzle again checked strainer and brush and vac (but wasn’t very dirty) combustion test etc again and it sounded smooth. Now two days later she called and said it’s doing it again. I’m at a loss

Big Ed_4

Check the oil supply for blockage or air leaks , Burner coupling could be slipping ....

EBEBRATT-Ed

Is the oil line gravity feed or is it a suction lift? If it is a lift you could have an air leak in the suction line. I would also check the chimney for an obstruction. Is it an outside tank with cold oil?

FLGhp22

Thanks guys, both good advice. Yea the tank is buried outside and far. Customer said he got a delivery I think like a day before I was there but said it was at half a tank. Don’t know if that’s true but I was thinking of blowing back the line. Thanks guys appreciate you 🙏🏻

Kickstand55

Before you blow out the line be sure and absolutely know if there is or is not a check valve downstream. You'll get an awful surprise.
Instead, perform a vacuum test on the supply line. Make note of the reading.
Question: Is this a 2 pipe oil supply and return?
If there are compression fittings anywhere in the lines, change all of them to flare fittings.
Not sure how much experience you have with buried oil tanks and lines, just be careful, know which is supply and return, don't mix them up.
Is there a 2 stage oil pump aka fuel unit? If not, it should be.
Does it have a Tiger Loop oil de-aerator? That should be connected to the old supply line only.
Do your homework. Suntek has information on oil line sizing, length and fitting types as well as vacuum limitations for oil pumps.

HVACNUT

What make and model boiler?
What burner?
What nozzle?
What pump pressure?
What type and condition chimney?
What were the combustion numbers when the tune up was done?

"Wasnt very dirty" after 2 months is too dirty.

If it's an old tank, it's  possible the delivery stirred up the sludge and it got sucked in if the burner was running while the delivery was being made (especially if 2 pipe), but no CO2 guns. Push/Pull pump.

If clients don't want to properly address their sludge issues, I tell them to shut off the Emergency switch before delivery, and wait a half hour after the delivery to turn back on.