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Three flashes, then okay again.

My furnace stopped blowing warm air, so I checked it. The flame was out and the "code" was three flashes. I turned off the heat. The HVAC guy I called said that meant the pressure switch. The next day, he came out and said everything was fine - that it wasn't showing the code and it was working fine.

Does that happen? (A code is shown, then resolves itself)? I read that the pressure switch is a safety thing, so I'm worried now.


  • JStarJStar Member Posts: 2,668

    Well, two things could be happening...the pressure switch could be bad, or the pressure switch could be doing its job. An error code will not tell you which one is correct. Usually, pressure switches are fairly reliable and only cause an error for a legitimate reason, such as a blocked chimney, or faulty inducer motor. It is indeed something that needs to be investigated further.

    Did your tech perform a combustion analysis or inspect the chimney?
    - Joe Starosielec
    [email protected]
  • Jamie HallJamie Hall Member Posts: 6,029
    And yes,

    if the problem causing the error code is intermittent, and clears, then you may be able to reset and run without the code.  Until the problem reoccurs...

    You really do want to find out why it occurred and get that fixed. 

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-McClain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
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