Sputtering Oil Burner - Contractor Talk - Professional Construction and Remodeling Forum

**Leo G** · 02-16-2007, 12:37 AM

I've got a Slant Fin L-30-P furnace with a Beckett model AFG burner, 16 years old. Recently the burner has started to sputter. While firing it will momentarily stop firing very briefly most of the time but it has gone as long as 3/4 of a second before recovering. This is on and off, mostly firing well but it comes and goes in spurts.

What I did.

So far I have cleaned out the heat exchanger/flue with the proper brush.

Still sputters, just as bad.
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I removed the nozzle/spark assemble, cleaned it and set it back to factory specs.

Sounded like it was firing better, but started to sputter after about 30 seconds of smooth operation.
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Cleaned the metal strainer, it was pretty bad.

Took a short time to get it to fire back up, had a hard time bleeding it, foamy fuel.

This time after initial sputtering from inadequate bleeding it ran sputter free for about 20 minutes. Then started again, not as frequent.
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Replaced the filter element after the oil tank, it was pretty bad too.

Same thing, ran for a while before sputtering.
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Replace the nozzle, had a 1.00 GPH 80º solid cone and changed to a 1.25 GPH 80ºES solid cone. Every time the service guy came by he put in a smaller rated nozzle (1.1 then a 1.0). This is what he had in the truck. I bought the bigger furnace to help with the New England winters. I went over size on purpose. It originally came with a 1.25 GPH 80ºA hollow cone nozzle and was adjusted to almost perfect efficiency and no smoke using this nozzle. After I replaced the nozzle it sounded much smoother but still continues to sputter occasionally, but much better than when the problem first started.

Now before I go to the next step of throwing parts at it I was hoping to get some recommendations on what to do.

The next thing I would do is replace the 10,000v 23ma transformer, after that replace the high pressure fuel pump.

I know it is possible (unlikely) that I got a bad load of fuel. Is there an additive I can put in the tank to remove water in the fuel? If so how much for each gallon (275 gallon tank)?

Any other recommendations would be appreciated. Thanks.

AirPro · 02-16-2007, 04:09 AM

Sounds like you have air or water in the lines. If you are dead set on changing parts yourself, I suggest you spend the money to have a DIFFERANT(qualified) heating contractor at least diagnose it first, why pay for a xformer and pump, when all you needed was an airflow adjustment? That can easily be determined by a $100 service call, and might not cost you anything in parts. Call a differant contractor!

Good Luck.

jmic · 02-16-2007, 07:03 AM

Leo do you get your fuel from the same supplier all the time or do you shop around for the discount prices? Sounds like you could have gotten a bad ld. of fuel and seeing that filter would probably confirm that. Did you change the filter on the tank yet? What did that look like?

**Leo G** · 02-16-2007, 08:02 AM

Ya, I get my fuel from the same source, for 19 years now. I don't need to shop around, I usually get a contract and make out in the deal. This year was the first year I think I lost out (damn). The oil tank filter was pretty coated with sludge, just like the screen in the burner. The stone filter on the backside of the nozzle was extremely clean. I changed the tank filter last night and haven't really spent the time waiting around to hear if it was still sputtering. After I started it up it was and a short while later it was. But that didn't give it time to totally clear the single, gravity fed line of air if it had been in there. If it is water in the fuel it should go away on its own after in get burned, correct. I have a service call coming up the 28th for a cleaning. I do my own service on the unit and once every 3-5 years I bring in a qualified tech to check out the system. I installed it, had a tech set it up and adjust it, and now I maintain it. Not really rocket science, most things are common sense. Once it is set up it should not have to be adjusted unless something moves. All the airways are clean and at original settings. It is still working well enough for me not to worry about going cold, but it's not running at 100% like it has been for the last 16 years.

72chevy4x4 · 02-16-2007, 08:51 AM

it is possible you have a slight leak in the piping between the furnace and the tank. I had one so slight, that the furnace would lose prime after an extended perior of being off (>25 minutes). Did you switch out the filter at the tank?

**Leo G** · 02-16-2007, 10:01 AM

Quote:

Originally Posted by 72chevy4x4

it is possible you have a slight leak in the piping between the furnace and the tank. I had one so slight, that the furnace would lose prime after an extended perior of being off (>25 minutes). Did you switch out the filter at the tank?

Yup, changed it out, pretty gooked up, been in there for 2 yrs (oops), didn't look like any water in the system, but I'm not sure exactly what to look for. But I'd think I'd notice it if it was there. I'll check on the system tonight and see if it has smoothed out. It should be air free by now if that was the problem.

**Leo G** · 02-17-2007, 12:20 PM

Well it seems that everything that I did resulted in the furnace running correctly. It took a while for things to smooth out so it was either air or water in the line. Not sure which and not sure if that was the problem. I did so many different things and nothing seemed to help immediately so that why I'm thinking air or water. But who cares, it's running right and I didn't loose any heating time or any big money on a service call.