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Soot in 5 months

Robert_H
Robert_H Member Posts: 189
in Oil Heating

I was distressed today to find soot in the pipe and heat exchanger of a boiler I did the annual service for in September 2024. I've been servicing this boiler for 3 years. Today I was replacing the water feed etc (separate post) and I pulled the pipe for better access and found the soot.

Burnham V-14A-T, Calls for a 100-80A and 100 PSI. I have been running a 85-80A at 140 PSI.
This was the final CA in September, Zero smoke -1% CO2 breach draft -.03.
Tstack 647
O2    4.9
CO    11
EFF    79
ExAir   28.5
CO2    12.03

This is CA as found today
Tstack   560
O2      4.5
CO      15
EFF       81
ExAir      25.6
CO2       12.33

Draft in the breach between -.03-.05 OF -.01-.03 (windy)

The pipe had thin coat of soft soot. The HX had between 1/8 and 1/4" of soot laying on the top of the hx visible with the pipe removed and the pins were coated, at least what I could see from the pipe connection. the firebox was soot free.  I cleaned the pipe and vacuumed the top of the HX through the pipe hole and will be back to thoroughly clean this weekend, pull smoke, CA etc. the soot sucked up easy as if it was just laying there.

I'm not seeing a big difference in the CA values at least not what I would think would create soot but I'm still learning. Is there anything standing out in these CA values?

And, besides a good cleaning and tuning is there something else I should be looking at.

Thanks

Robert

Comments

  • Steamhead
    Steamhead Member Posts: 17,680

    Sounds like the flame is impinging (touching) something it shouldn't.

    What burner is on it? Did the target wall detach from the back of the firebox and tilt toward the front?

    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    HVACNUTSuperTechLong Beach Ed
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 17,478

    Agree with @LRCCBJ

    Your adjusting the burner too tight.

    People don't believe this but things can actually change:

    The blower wheel picks up some dirt

    The fuel supply is different quality

    the temp of the combustion air changes

    the temp of the fuel changes

    The draft changes based on outdoor air temp

    etc etc

    There are many variables. You should adjust the burner to 0 smoke where if you closed the air any more it would lead to smoke. Then open the air until the Co2 drops 1%-2% from where it was at 0 smoke.

    This leaves a little margin or cushion to work with.

    There is no sense trying to get the last bit of efficiency out of a boiler to risk getting soot. The fuel saved is nex to nothing

    I wouldn't run anything over 12%, 11.5% is probably better.

    SuperTechLRCCBJRobert_Htechforlife
  • HVACNUT
    HVACNUT Member Posts: 6,674

    I never liked that design with the angle plate. Check the chamber. Remove the front and vac from top and bottom. Stack temperature is too high. CO2 is too high. My Beckett OEM says 80°B, but that's not the issue. You don't pull a 0 smoke if it's not a 0 smoke.

    Robert_H
  • SuperTech
    SuperTech Member Posts: 2,563

    Use the method @EBEBRATT-Ed outlined above. I never leave a boiler like that running above 12% CO2. Make sure the combustion chamber is in good condition. What about the ignition components? Are they in good shape? How did the flame retention head look?

    It's also a good idea to check combustion during ignition, steady state combustion and and after the burner shuts down. You might find the CO PPMs are excessive during ignition, this might be where the soot is coming from.

    Robert_H
  • Leo
    Leo Member Posts: 772

    I agree with everything stated above about not setting things too tight. I would also change the nozzle AND check the igniter. I didn't see zero smoke in your second set of readings but if it was the igniter is suspect. Dirty start ups can lead to soot.

    Robert_H
  • Robert_H
    Robert_H Member Posts: 189
    https://forum.heatinghelp.com/discussion/comment/1846995#Comment_1846995

    All good stuff thank you. So testing during during ignition, during steady state and during shutdown sounds great my question is if I see hi Co during startup what does it mean I'm assuming it means delayed ignition. And what about after shutdown if I see high CO what comes to mind for me would be I've got an after trip that's burning off… sorry for asking amateurist questions but the guy I work for is not a big CA guy. He did buy an analyzer in a smoke tester and I end up buying my own. And yes I do need to take some classes and am working on that.

  • Steamhead
    Steamhead Member Posts: 17,680
    https://forum.heatinghelp.com/discussion/comment/1846981#Comment_1846981

    This boiler also has cleanout plates under the jacket on the right side.

    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • SuperTech
    SuperTech Member Posts: 2,563

    If you are measuring high CO after ignition I would start by checking the ignition components. Ohm test the igniter. Make sure the electrodes are properly adjusted and in good condition. I would check the cutoff on the oil pump. The nozzle could be dripping after the burner shuts down, that would cause high CO and smoke during ignition. Was there any oil in the burner chassis or the air tube?

  • Robert_H
    Robert_H Member Posts: 189
    https://forum.heatinghelp.com/discussion/comment/1847077#Comment_1847077

    yes, it does

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 17,478

    I would not be concerned about CO on start up or shut down. You do want to make sure that you have a solenoid valve or clean-cut pump to keep start up and shut down cleaner. You're going to get a little bit of erratic reading on start-up and shut down while good combustion is established.

    Robert_HHVACNUT
  • SuperTech
    SuperTech Member Posts: 2,563
    https://forum.heatinghelp.com/discussion/comment/1847107#Comment_1847107

    Combustion testing during the entire burner cycle is something that the NCI recommends. I have found problems this way, things like the nozzle dripping after the burner shuts down.

    And I wholeheartedly agree that all burners should have solenoid valve or clean cut oil pump. I also prefer to have a modern primary control setup for interrupted ignition, 10-15 second trial for ignition, pre purge and post purge.

  • techforlife
    techforlife Member Posts: 120

    I would make sure that there is enough make up air to the burner. Some houses are very tight with little air infiltration. Also I agree about CO2. I like to set to 11 to 11.5% in case the cat or dog walks past the burner. We have to be practical if we expect our adjustments to be satisfactory for a year or more.

    Robert_H
  • Robert_H
    Robert_H Member Posts: 189

    Or the dryer vent is next to the boiler God forbid

    techforlife

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