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Oil burner set up?

don_185 Member Posts: 312
I would think that your 02 numbers would be more important then the co2 numbers.

High stack temps are not a sign of impingement.High stack temps are a good indicator of too much air,overfire or a poor design hx.

I've seen distort burner cone that would throw off the smoke trace and with higher air adjustment as being the fixed.


  • Just cleaned...

    a VERY dirty boiler and nearly clogged flue. The HO said he had it serviced every year so either he's full of it or his previous burner man never opened anything up and cleaned it. So I spent like 3 hours doing so, put it all back together and the best I can get it to do is 8% CO2 with a trace of smoke / 75% Eff on my analyzer. Gross stack was 640*. 80ppm CO. I vacuumed out the chamber as best I could but there's only one bolt and a lot of furnace cement holding the burner on so I didn't want to remove it for fear of never getting it back together. I have a feeling maybe the flame is impinging on any debris that might still be in there but that's just a guess. No way to look inside. He IS going to have me replace the boiler ASAP with a gas fired mod con but the gas co is dragging their feet about putting a line into his house so the boiler service is just a stop gap until they get off their you know whats.

    Any suggestions or input?
  • don_185
    don_185 Member Posts: 312

    Without the o2 number one could only guess.

    co at 80 ppm does not look bad however, the co2 and stack temps point to high primary air.

    Maybe it just the design of the boiler.Maybe its a distort
    burner cone thats mess up air pattern and depending on smoke trace only, is the reason for high stack temps.

    Get all the numbers next time and maybe we could have a deeper discussion.

  • Ken Field
    Ken Field Member Posts: 127
    Impingement ispossible

    especially if you brushed it out and can't get to the combustion chamber. The stack temp is high and I wonder if it is overfired? You didn't mention brand or model (which might help). If there are air leaks into the combustion area, the CO2 will be low. In a case like that, we make sure the combustion settings are all correct and then set the combustion up by smoke. Take the CO2 readings and thay are what they are. You have to get to zero smoke or the whole thing will repeat itself before next year. Keep in mind that the actual flame CO2 reading may be higher but with it being diluted, it ruins the efficiency shown on the tester.

    Ken F

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  • Thanks,

    yea, I'd say it's probably leaking air in around the burner flange so that would explain the low CO2. I stuck my 1" vacuum hose down in through the air tube and sucked out what I could. Then I pretty much did what you said, cleared the smoke up and left it at that. I didn't pay attention to the brand to be honest but I do recall it having a max input of 1.85 and I have a 1.10 nozzle in it so I don't think overfiring is an issue. I think residue stuck between the pins is probably causing the high stack temp. I did the best I could with cleaning it out, the thing was as close to plugged solid as I've ever seen. I've NEVER seen an 8" flue so jammed up, there was maybe an inch gap between the top of the horizontal run and the soot. Unbelievable how it even worked at all. I came out of it one black and smelly dude. LOL...
  • yep

    too much air would probably be the answer, I'm sure air is getting in around the burner flange. I got it down to a trace of smoke and I made it very clear to the guy he needs to get that gas line in so we can replace this piece o junk. I'm new with the analyzer so I'm still used to just looking at CO2 and stack temp. That was gross temp BTW net was more like 580* as it was 70* in the basement.(still high, I know. I don't do a whole lot of oil so I admit to being weak at troubleshooting a problem like this. I usually put them in new, set them up once with the old Bacharach kit and never see them again. This guy is an aquaintance/architect I've worked with, which is why I'm even involved with it in the first place. Didn't want to say no. The thing is a real junker, I made that clear to him. He's all for changing it but getting the gas co to do anything around here is next to impossible and he doesn't want another oil unit. Wouldn't a still fairly dirty HX also lead to high stack temp? I know I didn't get it spotless, although I tried to. The burner cone was in good shape. I cleaned it all up too.
  • don_185
    don_185 Member Posts: 312

    yes, if its dirty that to would lead to higher stack,so will flow problems.

    I think you did a fine job.Your new stack temps do not look bad at all for a oil boiler.

    On to the next one.

  • Todd_34
    Todd_34 Member Posts: 6

    't pay much attention to the make of the Burner or the appliance that it is connected to?
  • Leo_16
    Leo_16 Member Posts: 37
    I hope

    I hope he is changing to gas because of price. It sounds like he would have good luck with oil if he had a newer unit. You say it takes a bit to get the local gas company to do anything, it doesn't sound like service will be any better.

  • World Plumber
    World Plumber Member Posts: 389

    What kind of draft do you have? If your draft is too high it will pull the heat right through the boiler. Also where are you inserting your prob? You might be in a hot spot. Beckett recomends you try to check the combustion at 18 inches from the unit. The location of the barmetric damper will dictate the closeness.Some of the old ones won't get much better. Especially if it doesnt have a flame retension head. Has the burner been upgraded?
  • Holy laminated crap!!

    I just realized, unless I'm mistaken (and I don't think I am) there was no draft damper!! Then again some people will tell you that's "OK". I'm so not used to working on existing oil units that I didn't even notice! Thank you, thank you for this lovely idiot of the year award! Guess I better call him tomorrow and see what he wants to do about it, if anything. Talk about a brain fart...
  • Eh,

    once they get the gas connected their part ends there. Price is one aspect but he's got an old gravity system and it's just begging for a nice Prestige. ;)
  • Thanks...

    I'll see if he wants to do anything about the draft damper situation I mention below, at this point I'd say it's not critical. Other than that, yup, I'm done with it.
This discussion has been closed.