Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

boiler burners, flame and pressure

aircooled81 Member Posts: 205
When the manufacture calls for 3.5" manifold pressure, what is the lowest pressure to allow at the manifold?
I have a boiler that has the yellow tips of the flames touching the cast iron sections of the boiler, and I am thinking of adjusting the burner pressure lower, to lower the flame height with-out losing blue flame.
Any suggestions?


  • Mike
    Mike Member Posts: 94
    Usually 3.5" is the maximum. Check the burner tubes, make sure they're clean inside and out. Do this before making any adjustments.
  • Jamie Hall
    Jamie Hall Member Posts: 23,310
    Without the proper equipment to monitor pressure (which should be what the manufacturer calls for, within a very small margin) and the combustion -- CO, CO2, excess O2, temp, all that good stuff -- playing with burner settings is chancy at best. IMHO.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • aircooled81
    aircooled81 Member Posts: 205
    cleaned the burners, checked gas pressure with manometer.
    no combustion gas analyzer, so the consenses is leave it at the manufactures spec - or the posted spec on the nameplate is the max.

    any opinions on flame height and impingement on the cast iron sections?
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,541
    If you don't have a combustion analyzer you're wasting your time.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • Steamhead
    Steamhead Member Posts: 16,842

    If you don't have a combustion analyzer you're wasting your time.

    Agreed. Sure, analyzers aren't cheap, but they're much cheaper than lawyers.

    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • aircooled81
    aircooled81 Member Posts: 205
    Can you recommend a good model analyzer?
    I looked at and have used the filedpiece sox3, but it doesnt do co.