View Poll Results: What is the cause of Control Board Failure

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  • Only the rates chewing the wire? size of fuse doesn't matter

    1 33.33%
  • Rats chewing wires blowing higher rated 5 amp fuse

    1 33.33%
  • number of times the 5 amp fuse was blown within a short period of time

    0 0%
  • Would the issue be the same if only 3 amp fuses during troubleshooting?

    0 0%
  • Did using 5 amp fuses cause the 24v side of transformer to melt?

    0 0%
  • Does using 5 amp fuse void the warranty?

    0 0%
  • Technician's responsibility for control board failure?

    1 33.33%
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Results 1 to 13 of 17
  1. #1
    Join Date
    Sep 2019
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    Acceptable Trouble shooting practices

    Recently an AC technician responded to my call after I noticed the thermostat no longer displayed information . . . Well, Here's what happened . . . Please review the attached PDF and let me know your opinion as to why the control board fried . . . I'm ready to answer any questions needed . . .
    Attached Images Attached Images
    Last edited by beenthere; 09-21-2019 at 12:47 PM.

  2. #2
    Join Date
    Jan 2004
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    Fixed thread.
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    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    Feb 2011
    Location
    Georgia
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    Fix the rat problem. The 5 amp fuse did not cause the board to fry

  4. #4
    Join Date
    Dec 2007
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    Who is Horizon, "... reported to Horizon..."?
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  5. #5
    Join Date
    Dec 2007
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    None

    All

    Other
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  6. #6
    Join Date
    Jan 2004
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    PA
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    Quote Originally Posted by pacnw View Post
    Who is Horizon, "... reported to Horizon..."?
    A large service company.
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    How many times must one fix something before it is fixed?

  7. #7
    Join Date
    Sep 2019
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    Thread Starter
    The board and the Transformer failed after for 5 amp fuses blew within about 15 minutes . . . Are you saying that the board components would not be affected by so many hits? The last occurrence did not blow the 5 amp fuse but that's when the board circuitry went open. Rat problem fixed!

  8. #8
    Join Date
    Sep 2019
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    Thread Starter
    I meant FOUR 5 amp fuses blew!

  9. #9
    Join Date
    Jan 2004
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    PA
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    It might have had an effect, it might not have.

    The outdoor unit control wiring short does not actually go through the circuitry of the board.
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    How many times must one fix something before it is fixed?

  10. #10
    Join Date
    Feb 2011
    Location
    Georgia
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    Going through so many fuses is only a sign of inexperience. Hardly any evidence that you are owed any freebies


    Sent from my iPhone using Tapatalk

  11. #11
    Join Date
    Nov 2006
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    Southeastern Pa
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    An "out of spec" 5 amp fuse would not cause a board to die. In order to give a better cause than the rats chewing on the wire, I would have to posses a service history where I was the tech doing the work. Boards fail often, and without any fuse changes or fuses blowing. Sometimes, an examination of the board can suggest a cause, but since the board is generally not repairable, those investigations are rare.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
    Member, IAEI

    AOP Forum Rules:







  12. #12
    Join Date
    Aug 2002
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    I could see using 5amp fuses could have caused undo stress on transformer, though transformer may have already had damage from age or intial rat caused issue.

    However, the circuit board will not be damaged from a 5amp fuse. That is purely coincidental.

    Major rat issue was your main issue. Go after the rats for cost issues.

  13. #13
    Join Date
    Nov 2006
    Location
    Southeastern Pa
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    It is also worth noting that a transformer can burn up without ever opening its protection, when the current is consistently high but just under the protection value, allowing enough heat to accumulate from a turn to turn short that it eventually reaches the point where it pulls enough current to let the smoke out.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
    Member, IAEI

    AOP Forum Rules:







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