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Burner Runs after Flame is Out

abro42 Member Posts: 12
Weird problem, trying to understand why the following occurs.

Call for heat, burner fires, flame in boiler for 2 -2.5 mins. Next lame goes out and burner still runs for another 2-3 mins. Is this normal?

Faulty Aquastat (L 224U) on oil fired boiler? Recently installed Honeywell ODR ( W8735S1000) and programmed Aquastat for defaults designed for Northeast winter months. Noticed the flame out and burner run condition last year w/o ODR but thought nothing about it. Now its time to troubleshoot and resolve. No error codes on Aquastat.

Burner controller is Carlin. 50200. No error codes displayed.

Thoughts? Recommendations? Any concerns?

Thx guys. Best site for knowledge and experience for radiant heating and controls. really helped me on other issues. Very much appreciate the input.


  • rick in Alaska
    rick in Alaska Member Posts: 1,457
    Depending on the heating unit, and the venting, it could be normal. Some heaters need to "post purge" the exhaust products after the burner shuts off in order to clear the fumes from the firebox. This is especially true if it is a direct vent appliance. There is one out there that purges for 8 minutes!
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    There's no post purge on that primary control. If the burner is actually running you have a serious problem. Hopefully it's not sending oil into the chamber the entire time...or KABOOM!
  • unclejohn
    unclejohn Member Posts: 1,833
    No oil spray right just the burner motor?
  • SuperTech
    SuperTech Member Posts: 2,155
    edited April 2020
    Do you have a chimney or is it power vented? Most Field Controls power venter controls have post purge for the burner built into them. Post some pictures if you aren't sure of what you have.
    CTOilHeatrick in AlaskaZman