Oil burner noise

Rickoo

Hi,

We have a 24 year old Peerless boiler with a Beckett AFG burner.

We had some arcing type noise coming from the burner motor and a very slow oil leak dripping from the bottom of the burner housing. Tech replaced the oil pump and the motor. New motor is physically smaller and is a Sid Harvey MTR081.

The boiler is in the basement and throughout the house we've always been able to tell when the burner fired. Lying in bed on the second floor and at the other end of the house, I can hear it. I'm assuming it was from vibrations spreading throughout the piping system. The sound was subtle, but you knew when the burner fired. Never really bothered me.

This new Sid Harvey motor is MUCH louder and bothersome. Not in the basement, but in the floors above. The drone/vibration is much more pronounced. Not sure if this is a common occurrence with this motor. Keep thinking I'll get used to the sound but not sure that's gonna happen.

Don't think there's anything wrong with the Sid Harvey motor. Just assuming that's the way they are.

Any suggestions? Try a different motor maybe?

Thanks!

Jamie Hall

Is the oil line from the tank to the pump touching any of the piping anywhere? Or even fastened tightly to a beam? That can transmit a lot of noise.

Intplm.

Was the burner serviced when the motor and pump were replaced? I would call them back and have them make necessary tune up adjustments.
From the description it seems you have some air adjustments that are needed. Possibly the airband and the barometric damper?? Excess oil in the combustion chamber?
Best to have them come back and hear the burner running.

Rickoo

He did a combustion test before leaving and seemed happy with the results. I could post the numbers if that's of any interest.

The burner sounds perfectly normal (to me) in the basement at the boiler. It's upstairs that's the issue. Sleeved oil line is routed along the base of the foundation wall, over the floor to the burner. Oil tank is around 10 feet or so from the boiler. Line doesn't touch anything and wasn't modified during the work.

The sound definitely intensified when the burner motor and pump were replaced which leads me to believe it's one of these that's causing it.

Intplm.

Yeah. Can't hear it from here. Best to have them back.
But first, while the burner is running, grab hold of the oil line and move it ever so gently in different places and see if the noise changes vibration etc. If you find the issue, move the oil line away from what's making it resonate, and or add some pipe insulation around the oil line to silence the sound.

EdTheHeaterMan

The new smaller motor is probably not the problem. The new fuel pump may be part of the problem. The fact that the fuel lines were disturbed during the fuel pump replacement may have changed the harmonic balance of the fuel pump gears and the fuel line(s) that connect the pump to the tank. The vibration of the pump thru the fuel line that is fastened to the house in some fashion may now be acting like an acoustic amplifier. To test that theory, you can have someone carefully move the fuel line in the boiler room and along the rout to the tank, while someone is listening upstairs. (this reminds me of adjusting the TV antenna in our attic while someone is watching the screen downstairs) If you find that noise goes away then wedge a piece of plastic between the fuel line and the wall or joist where the noise stops being annoying. A piece of plastic milk carton or a piece of a credit card you need to cut up so your spouse does not bankrupt you are both good things to wedge between the fuel line and the wall.

There is one other possibility. The new coupling that may have been replaced with the motor and pump. For years I would carry the universal coupling kit. That kit has a piece of rubber tubing with an inner hex or sprocket that will accept the end caps that match the motor or pump shaft. The universal rubber tube coupling is about 6" long, then you cut it to size to match the oil burner you are working with.

Back when there were still hundreds of different oil burners from the 1940's 50's and 60's this made sense. But today you basically find Beckett oil burners so I carried one or two universal couplings and a box of Beckett couplings and one or two Carlin couplings. Why am I telling you this? What if the burner coupling was cut a sixteenth too long. That would cause the pump shaft to have a little more tension against the gears in the pump. That can make the noise you are referring to. To test that, you need to loosen the two bolts on the fuel pump about one full turn each. If that stops the noise, then your burner man needs to return to cut the coupling properly.

Ask me how I know this? LOL

Rickoo

Thanks. Will have a closer look at that.

HVACNUT

Rickoo said:

He did a combustion test before leaving and seemed happy with the results. I could post the numbers if that's of any interest. 

Yes, it's of every interest. Draft and smoke readings would be good too.
Was a printout from the analyzer left, or the report emailed to you directly from the analyzer, or is it hand written?

Does the tech know what the pump pressure was on the old pump?
Does the tech know what the pump pressure is on the new pump? (Factory set at 100 psi).
Does the tech know what pump pressure Beckett specs for the AFG in your model Peerless?

What make and model primary control (reset button) is on the burner? Does the new pump have a delay oil valve? Did the old pump have one?

The old burner motor was probably a split phase where as the new one is a PSC motor. Same RPM, More efficient. Less starting torque needed.

EBEBRATT-Ed

Sometimes the alignment between the pump and motor are off a snitch.

There are two screws mounting the pump and two screws or bolts mounting the motor'

Try loosening both pump screws just a tad while the burner is running and see if the noise changes. Do not remove them