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Fuel pump keeps tripping

1704 Views 22 Replies 6 Participants Last post by  beenthere
I have an old Weil McClain oil burner and the fuel pump trips about twice a week. I had it serviced and its still the same. When I push in the pumps button then hit the transformer reset button it fires right up and doesnt burble too loud or have a fuel smell like it was loaded up with fuel which tells me its starving of fuel then trips. Im a novice so bear with me but could it be anything else besides the fuel pump itself? Anyway to test the pump? How hard are these to swap? I already put a new control box in it 2 years ago so I doubt its electrical.
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When was the lat time this burner was cleaned and serviced? Needs to be done annually. Could be the filter at the tank, the pump strainer, the nozzle, ignition transformer , electrode adjustment . I would check the filter and pump strainer first.
Do you mean it's tripping the primary? The oil pump can be tested with a oil burner test manifold. The pump is an easy thing to change, but I'd not change anything until I could diagnose the exact issue. There's a lot of different things that can cause a burner to open the primary control.
This is the manifold I use.

When was your burner last tuned up, including a replacement nozzle, filter and strainer? And the furnace cleaned?
It was just serviced a week ago. Did it before and still does it. What donyou mean by the primary? Sorry I'm no pro to these things.
What did the combustion analysis show during service? Nozzle changed with the correct size? What's the electrode gap? Porcelain ok and not cracked? Retention head burned or distorted? What pressure is the nozzle running? What suction is the pump pulling? 2 pipe or single pipe? Is the tank above the burner?
The primary is the primary control of the burner.
Sorry I asked none of that. I guess I could call them to find out
The button your pushing on the side. Is probably the burner motors reset button. As oil pumps don't have a reset.

Either the motor has a dead spot in its starting winding, or the pump is becoming hard to turn, and over loading the motor.
Could you tell me how to diagnose those 2 things?
Next time it happens. Don't push the reset button. Carefully remove the motor, and see if the pump turns hard, or seems to have rough spots when you turn it.

PS: Its better to turn the pump using the coupling. Then by trying to turn it by its shaft only.
Awesome advice! So it just unbolts and pulls out? I dont think its the circulator pump cause it trips even when hot water isnt called for.
2 bolts. Then it slides out, sometimes a little hard.
Can you take a picture of the switch your resetting?
Does it look kind of like this?

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No that one looks like the one on top of my electric box. It's under the box on a black round pump. It's a little red square button. I have to push that in then hit the bigger red button on the electric box for the boiler to fire up.
Ok, that's the motor overload switch as suggested above. The black round thing isn't a pump, it's the burner motor.
Ahhh thanx I love learning from you guys! So what does this motor do?
So what does this motor do?
Ayuh,.... It turns the pump on the other side of the burner, 'n the fan in the middle of the burner,.....
It makes your oil burner run. When you remove it, you'll find it has a squirrel cage blower mounted to it. Then, the end of the shaft will be inserted into a coupling, which is then attached to the oil pump on the other side of the burner. If the motor doesn't run, then the burner can't move and air and can't pump any fuel. If the coupling fails, then you have air but no fuel. Same of the pump fails, or looses prime.
Makes perfect sense thanx guys. Next te it trips I'll pull it and see why.
Should be able to pull it now and see. Plus, take an amp draw of the motor and see if it's close to or exceeding LRA, both with and without the pump disconnected.
might be to easy of an answer. We had a house that we checked and they had to many things on this circuit. This house had a ton of stuff pluged in though. So it might not apply.
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