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Beckett AFII 150 burner - not firing properly after PM

i have 2 identical furnaces, each Beckett AFII 150 burner with a .50 70B nozzle. i've owned them for 23 years and get them PM'd each year. This year i have a new repair company and they PM'd both of them. One of them is running fine, like it prior years. The other furnace runs but is firing with a flutter in the flame and smells of oil. they've messed with the pump pressure and the air dial, even swapped the electrodes/nozzle assembly between the units and the problem persists. they've been on the phone with Beckett with no solution in sight. i havea video of the furnaces running so you can see the difference but have no way to upload it to this forum. the first one is running fine, the second furnace is the one not operating properly.


  • Jamie Hall
    Jamie Hall Member Posts: 23,445
    Do you have the combustion test numbers for both burners?? What are they?

    I'ts obvious that the PM messed up one of them, but the question is... how?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,108
    It is unfortunate that you can't get the same company to do the maintenance. Did the person who did your work quit? Was there a bad experience? There is an advantage to using the same experienced people to keep your stuff operating properly. They know your equipment. Not all HVAC tech's are qualified to work on oil heat equipment.


    You have a part that is failing (like maybe a pump or a burner coupling) that did not show up until after the maintenance was completed. Can you get the contractor that just completed the maintenance to come back and check the combustion numbers?

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • michaelhepp
    michaelhepp Member Posts: 2
    Jamie - thanks for the quick response. i agree, something got messed up in the PM. 2 techs came, 1 seasoned and 1 "in training". guess which burner the training guy worked on?....

    there were here late friday night troubleshooting and i apologize as I wish i had written those numbers down to share.
    HVACNUT Member Posts: 5,865
    edited November 2021
    Does the burner ever go into safety, or it runs like that?
    The AFII can be finicky. The gears of the air dial have been known to break and you can adjust it from 0 to 11 and not get any change. 
    The door access to the nozzle assembly sometimes doesn't seat right and disrupts the static pressure. 
    Where is the oil tank? 1 pipe or 2? Could be a suction leak. 
    23 years, does it have a delayed oil valve? 
    Is it interrupted ignition? Model of primary control?
    I believe pump pressure is 140 psi. It should be stated in the cabinet or right above the fuel pump.
    And it ran fine before it was serviced, or was it the first time it ran for the season? If the first time, check for an open heat exchanger. That would be a change in over fire draft going from negative to towards positive when the blower motor comes on.
    With the right tools and gauges, and analyzer, and smoke gun, it shouldn't be too hard to find.
    EBEBRATT-Ed Member Posts: 15,629
    Could be a slipping pump coupling
    rick in Alaska