Sputtering Oil Burner

Leo G

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.

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AirPro

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

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?

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Leo G

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.

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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?

Leo G

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.

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Leo G

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.

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Roy Hinkley

Same sputtering issues. I found a bad gasket on the pump - enough for air to get in the oil. I had a spare pump, so just replaced the whole pump to resolve the leak.

beenthere

I hope all those air settings aren't the same as when it was installed.

A 1.25GPH nozzle needs more air then a 1.0GPH nozzle.

So if it had the same amount of air when it was a 1.0 nozzle as a 1.25 nozzle. You were cooling the flame, and wasting lots of oil.

Leo G

You do realize that this thread is from 2007?

I'm sure the tech who performed the nozzle swaps changed the air bands.

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beenthere

Yeah, I saw that its from 2007.

Just wanted to point out the problem with you saying all the air settings were the same as when it was installed. After posting that it has had different nozzle sizing installed in it.

Unless you see a tech making the adjustments. And running a combustion test. Don't assume.

Seen lots of units that a tech just eyeballed it.

Leo G

I only have them come every three years. I do the in between cleanings. When they come they do an efficiency test which includes a smoke test. I'm sure it would find any ill adjustments. It has been lowered to a .95/gal now. They are pissing me off by doing this. Next time they come I am bumping it back to a 1.1/gal. I wanted a furnace with a bit of overkill. I don't want my furnace to run 100% at 0ºF. And I want unlimited hot water like I had before they dropped it to 1.0/gal.

See what you started.

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beenthere

Tell them. that you will NOT pay for any nozzle that is not factory spec.
Before you do that though. Make sure that your boiler isn't listed for a nozzle of the smaller size they are putting in.

Leo G

The boiler is rated for a 1.0, 1.1 and 1.25.

I'm sure the .95 squeaks by. But they are trying to get me down to a standard .85/gal. My house is old and very little insulation. I would freeze with that range nozzle in the winter as soon as we got below 10ºF. Next time they come I will tell them beforehand to bring a 1.1/gal 80ºES hollow cone nozzle. Which is what is specified for the burner. I think it can be substituted for a 80ºW.

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beenthere

Es, is extra solid.
There is no extra solid hollow nozzle.
Because it wouldn't be hollow then.

W is special solid.


So you think your house takes more then 95,200 BTUs to heat it, when its 0° outside.

Leo G

Did I mention very little insulation and cast iron radiators and single pain glass?

That is interesting. Maybe I am mistaken on the ES and that is what they put in there. I do remember it was suppose to be a hollow cone spray pattern. It is a Slant Fin L30 with a Beckett burner in it. About 17 years old.

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beenthere

So a load calc was never done.

Cast iron rads. Hard to beat for heat.

Leo G

Nope no calc. The original burner was a 1.25/gal/hr and before it blew a hole in its side it worked well. So I got the same size and downsized pretty quick. The efficiency of the new burner was measured at 86% when it was new which I am sure was about 15 points higher than the older one it replaced. Last time I got the efficiency checked it was at 84%.

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beenthere

So the new one, is probably able to output about 13% or more(depends on what old units efficiency was) heat then the old one.

Another quick question.
On your new boiler. Is the input rating up to 175,000. Or is it rated higher.
Many newer boilers use much higher oil pressure then the old ones did.

Example. Old units were 100 PSIG oil pressure. Newer units often use 140 or 150 PSIG oil pressure. Which of course increases the amount of oil that goes through the nozzle.

Which would make the new boiler larger then the old one.

Leo G

Not sure. I think the pump is 90PSI

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