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  1. #1
    Join Date
    Jan 2020
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    No voltage at thermostat but 24 volts on furnace control board ...

    So the thermostat isn't working. Multimeter says no voltage at thermostat. Where the thermostat wires attach to the furnace control board, I get 24 volts. Wire connections are tight. I don't understand how the control board wire connections have power, but 6 feet away at the thermostat the same wires have zero voltage (of course a break in the wires would explain, but the wires haven't been touched).

  2. #2
    Join Date
    Aug 2002
    Location
    Southold, NY
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    How are you measuring?

    Maybe call for service!

  3. #3
    Join Date
    Dec 2007
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    9,471
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    Quote Originally Posted by pecmsg View Post
    How are you measuring?

    Maybe call for service!
    What terminals are you measuring/checking?

    External safeties?
    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

  4. #4
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    Jan 2020
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    Thread Starter
    On the control board ... one probe of the multi meter stays on R, moving the second probe between all the other connections (white, yellow green blue) I get 24 volts.

    On the wires at the thermostat I get zero.

  5. #5
    Join Date
    Nov 2006
    Location
    Athens, Ohio
    Posts
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    Are you a tech?
    AOP Rules: Rules For Equipment Owners.

    Free online load calculator: http://www.loadcalc.net/


    There = not here. Their = possessive pronoun. They're = they are
    It's = contraction of it is. Its = the possessive form of it
    Too = also. To = expressing motion. Two = 2
    Then = after that, next. Than = indicates a comparison.
    Questions should end with a question mark "?" Statements end with a period "."

  6. #6
    Join Date
    Aug 2002
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    Southold, NY
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    With 1 lead on R?

  7. #7
    Join Date
    Jan 2020
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    Thread Starter
    Yeah. "R" ... "R" the red power wire.

  8. #8
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
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    So
    R to G zero volts?

    What does that tell you?

  9. #9
    Join Date
    Jan 2020
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    Thread Starter
    I can jump the heat on at the furnace control board, but can't jump it on at the thermostat. Bad thermostat wire?

  10. #10
    Join Date
    Oct 2014
    Location
    Saint Pail, Minnesota
    Posts
    756
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    Is this a Nest thermostat?

  11. #11
    Join Date
    Aug 2002
    Location
    Southold, NY
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    Quote Originally Posted by mr.magoo View Post
    I can jump the heat on at the furnace control board, but can't jump it on at the thermostat. Bad thermostat wire?
    Yes
    No
    Maybe



    I agree with is this a NEST?

  12. #12
    Join Date
    Jan 2020
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    Thread Starter
    Not a NEST. A 10 - 15 year old Trane programmable thermostat.

  13. #13
    Join Date
    Jan 2004
    Location
    PA
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    https://hvac-talk.com/vbb/showthread...ad-these-rules

    2. Do-It-Yourself (DIY) - not here.

    This site is for industry professionals and folks seeking HVAC/R advice and knowledge. Please do not ask for step by step instructions on purchasing, installing or repairing your own equipment. This is our job and our livelihood. We are generous, but not to a fault.

    Questions of this type will not be answered and may be deleted at the discretion of the Moderators.
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