Ask Me Help Desk - Beckett model AFG burner flame-out

This season is the first time ever that this has happened. The furnace starts, gets a flame, runs for a while, then it flames-out. It sounds like the oil pump is still running (I hear like a spraying sound). Nothing shuts off. Then the flame will come on again, but may continue flaming-out intermittently. The flame loss occurs at random intervals, and duration.

I suspect that it may be dirty oil particulates which are momentarily blocking the oil line. But then, I'm not an oil furnace expert. :confused:

The problem is most likely a dirty nozzle, Beckett oil units need service every year. This service involves changing the fuel filter, and oil nozzle, cleaning the photo cell, and rechecking the combustion, as well as checking / resetting the electrode gap settings, not to mention cleaning the boiler and/or furnace flue passages and flue, to be sure they are clear of carbon (soot) build up. And most importantly checking the safety's that they all work.

Sounds like air in the line or a vacuum leak in the supply oil line.

Post the Beckett model number ( oil burner ) for me... and the make of your furnace... THANKS..

Quote:

Originally Posted by tsa7man

Post the Beckett model number ( oil burner ) for me....and the make of your furnace...THANKS..

my beckett is doing the same thing fires up then quits,I have replaced the transformer bleed the line checked the eye, but no luck

Quote:

Originally Posted by tsa7man

the problem is most likely a dirty nozzle, Beckett oil units need service every year. This service involves changing the fuel filter, and oil nozzle, cleaning the photo cell, and rechecking the combustion, as well as checking / resetting the electrode gap settings, not to mention cleaning the boiler and/or furnace flue passages and flue, to be sure they are clear of carbon (soot) build up. And most importantly checking the safety's that they all work.

This is definitely NOT a bad nozzle. A bad nozzle is a constant problem from startup to shut-down, your problem only occurs after the burner has run for awhile, which rules oiut a bad nozzle. You need a new oil pump. Most pumps run at 100psi some up to 130+. Your pump gears are shot, which explains the intermittent flame. Changing a pump on a Beckett AFG is 2 bolts and the oil lines, very simple even for a beginner. The hard part is checking flame settings- draft(both chamber and stack), smoke, CO2 and visual. I'd have an experienced person do it if you're not familiar with it.

Now, I could be wrong. If by flame out you mean the flame chokes out, then you may have a clogged oil filter at the tank, (probably not the pump screen). Sounds like while the burner is off the filter can refill itself, but when it comes on it can choke out, until it has time for the clogged filter to retain more oil.

And also, as noted above, it's very possible that there's air in the line. In many cases though you'd also have an oil leak because where air enters at negative pressure, oil leaves at positive pressure.

It's an easy fix either way, don't let someone rob you with service charges.

Not sure if you are still monitoring this site... check the obvious first! Why does everyone go for the most difficult and then work backwards. My guess is that it is as simple as cleaning the face of the photo sensor. After time, some soot may develop on it and trick the system into thinking there is no flame, therefore, cutting out the fuel delivery. Change your filter, screen and nozzle (about $12 total) and wipe off the face of the photo sensor and you should be good for another few years!

Check an air leak if the pump is bad it won't light up at all, if the photo cell is bad it won't light up at all, if it has soot it won't let the burner function, ever. Check the pump strainer & oil filter before going crazy spending money, also check for an air leak. Seems like your getting oil up to the point that the air bubble reaches the nozzle then your flame goes out, as your pump continues to pump it eventually receives oil & thus you have a flame again. Tighten all the nuts, valves & fittings on the line.

I have to rehash this thread.

I am getting intermittent flame out as well on a Beckett RWB ( I was told it has specs similar to AFG), running a Danfoss pump. But it happens with a lot of time between flame outs. I have stayed around the boiler area for 2-3 hours and it won't happen. Then, in the morning, I'll have to press the reset button on the intermittent ignition switch.

A. I replaced the filter, the nozzle, let the air out of the line, and cleaned the photo sensor, and still have the problem.

B. There are NO obvious leaks that I can tell, so the vacuum is solid.

C. I think the pump is good because it is moving fuel through the drain hole very well, and when I pull back the power supply to the electrodes after the flame lights, there is a nice flame and no odd noises from the pump.

Question: Is it possible for the nozzle to be a bit too far back in in the tube and be hitting the heat shield which, in turn, at some point trips the photo cell and shuts off the burner?

I'd love some help with this...

Is it likely that this is cause by dirty fuel?

Would it help if I put mineral spirits in the tank?

Is it possible that the intermittent switch is faulty and causing this?

Quote:

Originally Posted by defibrilator

Is it likely that this is cause by dirty fuel?

Would it help if I put mineral spirits in the tank?

Is it possible that the intermittent switch is faulty and causing this?

Depending upon how oil is drawn from the tank you could have what I call a tank floater. Debris in the tank floats around and when it gets to the oil suction line going to the pump it plugs it up. When the unit shuts down it is allowed to float free and the burner will run for a while longer then it plugs up the suction line again and the process starts over.

Now before starting to play with the oil lines make sure that all parts of the burner are in tip top shape.

Motor current draw within spec.

Motor temperature rise in acceptable temp range (If you can hold your hand on the motor it should be acceptable) Note: the little reset button on the motor if so equipped does not always trip on high temp.

Oil pump at 100 PSI or the pressure rate for the burner you have.

Ignition transformer producing the correct amount of discharge and the current draw within specs.

Pump coupling in good condition.

Safety device be it stack control or cad cell detection working properly.

When I was a young man many years ago I had a call that taught me a lesson about oil burners. If you think something cannot happen it can and will. I spent hours on a burner outage call similar to yours. The dang thing would just run great and then 1/2 hour later would start to spit a sputter like a flame out but it would clear and keep running. The people had heat so I left for the day. I new a real old oil guy and bounced the problem off him by phone. We went step by step and we both agreed everything was setup OK and it should be working so I told him I was going to be sure of the oil supply was OK. I got a 5 gallon pain with a lid and filled it with number 2 oil then attached some spare copper to the pump from the bucket. Got the system running and told the people to keep an eye on it and just in case they did not I installed an old Amprobe chart recorder on the 120 volt line feeding the burner. It records over a 24 hour period and any deviation from the normal current draw would show up on the chart.

The reason it would show on the chart is the fact that when the oil burner is pumping oil it will draw more current than when it is free wheeling and not pumping oil so I figured the next day would tell the tail. Sure enough the chart was perfect except for when the burner would come to a complete stop after the heat call was satisfied and naturally that was expected. What this test proved was the fact that there was something stopping the oil in the oil tank from getting to the burner. I blew the lines clear so it had to be in the tank

Since most tanks do not have a clean out I set a new tank next to the oil one and then transferred the oil from the old tank to the new tank. I had placed a filter in line to trap anything that might be in the old tank as a precaution. Naturally I could not get all the oil transferred but only a few gallons were in the old tank.

I took a flash light and looked down the fill pipe hole of the old tank a thought I saw something so we flipped the tank over a big catch basin and glass, old style bottle caps and other assorted debris came out confirming a floater problem.

The customer was not happy with this but was happy that I found the problem. They ended up with a whooper of a bill but that is the way it goes. About a year later we were back out for the annual burner tune up and that is when I got the rest of the story. It seems some neighborhood kids were just having funs putting things down pipes and it just so happens that my customer was not the only one having burner problems.

This entire situation was great for business since I got a few more neighbor jobs and I sold everyone a fill pipe lock cap and pad lock so the kids could not put debris down the oil tank fill pipes again. It also taught me a big lesson in the fact that if you work hard and persevere your labors will be rewarded. If I would have just walked off that job without fixing the situation my reward of more service work from the neighbors would have never happened and my reputation as a fixer and not a replacer would have been tarnished.

I am sure you will find your problem since it is just a matter of time and determination.

Thank You for your reply. Very kind of you.

There was one thing I missed doing: cleaning the pump strainer on the Danfoss I'm running. I am green, and had thought that "strainer" meant the one on the back end of the nozzle (clean). It turns out there is a really nice one in the pump, that does its job real well; it was filthy. In any event, I cleaned it with engine de-greaser (I will try keeping to half a can next time). I hope this will do the trick, although I'd love to learn to use an multimeter and pressure gauge. These are handy skills.

I'll post back if this solution held or not.

I was starting to think about the floater issue myself. My tank is dirty with black sludge so it seemed very logical. But, as it turns out, the floater problem was occurring on the pump strainer.

I would check the upper Limit switch too (the safety one that is heat sensitive) I had reaplaced just about everything last year and it was a $30 switch. You can test by jumping it with a wire. Hope that helps someone in the future when they search for this prob.

Sounds like to me a fan limt switch if you have a hot air furance the box is getting to hot and shuts down the burner when it cools enough it restarts minor adjustment can also happen on a boiler

I had the solenoid go this year, on the cleancut pump, it just gets worse and worse.