Oil burner delayed firing problem

Jim K in PA

Hello,

This is my first post here, but I have been hearing about "The Wall" for years over on the OHW.

I tried to search for a previously asked question of this type without success.

I have a 1997 EFM oil fired hot water furnace. I have a variable propblem with the burner not firing as soon as it starts. Sometimes it lights off right away, sometimes it spins for a half second and lights, and sometimes it spins for 3-5 seconds and then lights with a "whump" and a puff of black smoke/soot out of the flame viewing port and the damper. Clearly the burner is injecting oil into the chamber, but it is not lighting off properly. I suspected that the igniters were not set right, so had that checked and reset (by a professional). New filters and new nozzle were also just done in the last two weeks. This has been happening for a couple of years now. I almost think it is like there is a relay sticking that is not energizing the igniters as soon as the T-stat calls for heat. It has a Honeywell control box. I can get all the details/numbers if they are necessary to diagnose this issue.

Thanks for any help.

Jim K in PA

Steamhead (in transit)

Where in PA

are you located?

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burnerman_2

ignnition

unless there is a delay valve as soon as the themostat has a call 4 heat both the motor and the transformer start at the same time no 1sec or 2 boom fire instantly if this is not happening every time 1.have transformer tested 2. gap for points 3. angle of nozzle if the nozzle was dropped it could be defective if this is a once in a while thing could be a voltage drop 115 volt in 10000 volts out so if 0nly 80 volts in may not be enough to ignite i like ignitors have it checked winter is on it's way royboy

bruce_21

How long has it been since the heat exchanger was really cleaned, I mean taking off the top of the jacket and running a long wire brush up and down inside to get all the soot crud out of the inside?

Jim K in PA

Bruce - the exchanger was opened up and cleaned thoroughly two weeks ago when the rest of the annual service was done. It was actually quite clean.

Jim K in PA

Poconos - northeastern PA

Jim K in PA

Burnerman - thanks for the suggestions. A voltage drop in the transformer could be the issue, but I am confident it is not the house current/voltage that is dropping. It happens about 20-30% of the time. The gap for the points you are referring to I presume is the igniter points - those were checked/set and were actually pretty much right on before resetting. I am really leaing toward an electrical issue. Before I started changing parts I wanted to get some feedback.

I'll get the transformer tested.

Thanks again for the input.

coalcracker

It may not have a transformer, but an ignitor instead. Was the oil pressure at the pump tested for 100#.

You can call efm directly.

coalcracker

Ignitors get weak and so do transformers. You could also have the air set too high and it will blow out the spark of a weak ignitor/trnasformer. It will try to arc again and again and when the right mixture is present it will fire. Your spray angle could be off, even with a new nozzle, but usually not with a new nozzle.

Jim Davis

Sounds like loss of prime or air in the system. This is often caused by a two-line system. Also caused by not getting the air out of the oil filter properly after changing. Should never use 100# pressure unless oil is heated to at least 80 degrees.

Chris K

some additional things i would look for

Loose pump coupling, pump pressure will not come up quickly, pump coupling can become loose and be a bugger to find if you forget to rule it out in your initial troubleshooting.

cracked ignitors, the ceramic parts of the ignitors can get small cracks and short out the transformer voltage.

dirty tranformer, lots of dirt around where the electrodes come out of the transformer can short the current.

too much air. as stated before this can lead to blowing the spark right off the electrodes, and also lowers your effiency.

Loss of prime? maybe, but you are getting a whoomp when it does light, usually a sign that you are getting oil, but if you have an air bubble right there when it starts it will not come up to pressure quickly and give you poor atomization and it is hard to light poorly atomized oil.

carbon bridging, most efm's came with afg burner fitted with an F head, check the head for carbon build up, this can build itself back to the electode tips and short the current. it can also build itself from one electrode tip to the other if they are intruding on the spray pattern.

That is all I can think of off the top of my head, leave us know what you find.

coalcracker

Also, was the Z setting ever changed or set?

Some burners use 140# of pressure. Maybe in the ideal world the oil temperature is 80 degrees, but I bet in 99% of the times, it's about 60. Never heard that one before.

Al Corelli_2

WOW

WOW! You guys are thorough! I can add absolutely nothing.



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Jim K in PA

Jim - it is a single line system and prime is not the issue. Plenty of head pressure before the pump, as the tank is a 274 vertical sitting on the floor about 8 feet from the burner. In-line cartridge and pump cartridge filters were both changed. Pressure was not checked, but burner condition was excellent, so we "figured" pressure was OK.

It really seems to be an ignition issue.

Jim K in PA

Chris - thanks for the points of concern. We will check (and re-check) what is in your list. I never though to call EFM directly for their input. I'll do that.