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  1. #1
    Join Date
    Nov 2019
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    Only getting 1/2 of the 28 VAC from the transformer

    43 year old air handler (apartment maintenance) , only getting 14vac in the unit.
    Reading 28vac at the transformer. Replaced the T-Wire from the tstat to the air handler . . . still getting 1/2 of the supplied low voltage available

  2. #2
    Join Date
    Oct 2011
    Location
    Chicagoland Area
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    So what is your question? You are losing voltage somewhere....Figure out where you are losing voltage and you have figured out your problem.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  3. #3
    Join Date
    Nov 2019
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    Thread Starter
    I thought it was odd to loose exactly 50% of what I should be reading on my meter

  4. #4
    Join Date
    Oct 2011
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    Chicagoland Area
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    You are either losing voltage or have phantom voltage at your load.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  5. #5
    Join Date
    Apr 2007
    Location
    Tucson, Arizona
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    1,286
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    Where are you reading 14v at, terminal strip at air handler from C to R? Is common grounded? What do you get from R to common at transformer? And from R at the terminal strip to cabinet ground? Do you have continuity from common terminal of transformer to ground wire at cabinet ground? What’s the power into the A/H, is it on the proper transformer terminal (208?)
    That’s about where I’d start my readings to figure out where it went wrong
    There are two ways to do things, Right and Again.

  6. #6
    Join Date
    Oct 2011
    Location
    Gladstone, Oregon (Portland)
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    New tech?

  7. #7
    Join Date
    Sep 2007
    Location
    edmonds wa
    Posts
    4,433
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    That old of air handler should be replaced, but it should be easy to trouble shoot. Leave one lead on xfmr common and use the other to follow the circuit around.
    UA Local 32 retired as of Jan 2020

  8. #8
    Join Date
    Nov 2019
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    Thread Starter
    Buford! Thank You ! I traced the xformer 28vac to the outside condenser contactor . . .wire biodegraded and grounding but not kill'n the xformer, "and" the one time resistor fuse was blown on one of the heat strips 😅👍🏻

  9. #9
    Join Date
    Jan 2004
    Location
    PA
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    78,377
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    Quote Originally Posted by Dirt Farm View Post
    Buford! Thank You ! I traced the xformer 28vac to the outside condenser contactor . . .wire biodegraded and grounding but not kill'n the xformer, "and" the one time resistor fuse was blown on one of the heat strips ������
    That's not a resister. Its a thermal fuse. To protect from over heating and starting a fire.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  10. #10
    Join Date
    Nov 2019
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    Thread Starter
    Ty been there, it looks like a resistor to me? :-)

  11. #11
    Join Date
    Nov 2019
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    Thread Starter
    I went through basic electricity and electronics in the USN in 1982 😅

  12. #12
    Join Date
    Sep 2002
    Location
    Virginia
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    There are no resistors in heat strips ….. just a thermal fuse (that looks very much like a resistor) that cuts power when it gets too hot

  13. #13
    Join Date
    May 2014
    Location
    Bay Area California
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    But, but, but . . . Isn't the heat strip itself a resistor?


    Quote Originally Posted by Snapperhead View Post
    There are no resistors in heat strips ….. just a thermal fuse (that looks very much like a resistor) that cuts power when it gets too hot
    I do a triple evac with nitro to remove non condensables.

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