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Just serviced oil boiler now sounds loud and rough

lindera Member Posts: 26
We just had our oil boiler serviced and it sounds louder and rougher when running. It also seems to smell more. I will call the contractor but was curious to hear opinions on what may have caused this. Thanks!


  • Jellis
    Jellis Member Posts: 228
    call the contractor back ASAP and make sure he performs a combustion analysis and leaves a report. If you can hear the "flame" making noise and are smelling something then dangerous conditions can occur.

    you should not smell a properly adjusted and working oil boiler.
    likely is a improper air/fuel mixture happening, could just be an adjustment, may need a new nozzle or other things.

  • lindera
    lindera Member Posts: 26
    Thank you. I'll call them now.
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,053
    After a tune up, or anything affecting air, oil, pump,or flame, a complete, proper combustion analysis is always required. Anyone who looks at the flame and calls it good is not a professional.
  • lindera
    lindera Member Posts: 26
    a combustion test was done. The contractor is here now, says it is running rough and mentioned the possibility of a fouled nozzle which is not something I am familiar with.
  • lindera
    lindera Member Posts: 26
    Contractor replaced the nozzle. Hopefully that will help.
  • SlamDunk
    SlamDunk Member Posts: 1,379
    If contractor did perform a combustion analysis, he should have left the results with you. If you could post them, it would be helpful
  • lindera
    lindera Member Posts: 26
    Here it is:

    HVACNUT Member Posts: 4,957
    321° net stack temperature.
    A Weil McLain GO-4 with a Carlin EZ 1.
    It doesn't seem as if the test was done at steady state or maybe it's under fired. Which would explain the noise and odors from the first nozzle. Maybe he downfired it. The burner should be fired at the WM spec'd rate. It should be stated on a yellow sticker on the side of the boiler.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 5,379
    edited December 2019
    The Weil McLain SGO -4 has a firing rate of 1.20 GPH and that is sometimes achieved with a 1.00 GPH nozzle at 145 PSI in some burners. If the incorrect nozzle firing rate, spray angle and spray pattern is not used, that may cause your problem. Since the latest repair and Combustion test (which looks good BTW) your problem should be solved. If you still have problems let us know what oil burner your Weil McLain boiler has. QB burner or Beckett or Other, brand. With this info, we can let you know what the proper nozzle spec should be! The paper behind the combustion test indicates you have a Carlin Burner with a .75 GPH 60° B nozzle and that also looks right for Carlin but slightly underfired, the Stack Temperature of 369° might a bit of a concern depending on your chimney arrangement. Masonry Lined 2 or 3 story home may have condensation problems. Manufactured All-Fuel chimney or Stainless Steel lined chimney is less a problem
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • lindera
    lindera Member Posts: 26
    edited December 2019
    Thank you all for your feedback. I learn more every time I'm on here. We had a Forever Flex stainless steel chimney liner installed in 2008.