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  1. #1
    Join Date
    Nov 2018
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    Fan delay in cooling mode

    Hi
    I am working on a carrier roof top unit. When I got here I found the filters plugged and the belt broke on the blower assembly. I switched out the belt and filters. I still had low suction pressure. What I noticed is the blower fan was not turning. It had a delay on it. During this delay the unit freeze up.
    MN# 48TFEOO7

  2. #2
    Join Date
    Aug 2002
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    Southold, NY
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    How long of a delay?

  3. #3
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    Nov 2018
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    Thread Starter
    I think it was about 3 minutes

  4. #4
    Join Date
    Aug 2002
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    That’s a long delay!

  5. #5
    Join Date
    Nov 2018
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    Thread Starter
    Ya I took some picks of the wiring diagram. Once I get to a pc I will post them here.

  6. #6
    Join Date
    Oct 2006
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    The Beach
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    You should be able to bypass the delay or get one with a lot less delay time.
    Blue Fox

  7. #7
    Join Date
    Nov 2011
    Location
    East Side
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    sounds like you have something else going on. a 3 minute delay would more likely be on a low pressure switch bypass before it would be on a blower delay.

    someone may have changed the timer and put in the wrong one.

  8. #8
    Join Date
    Dec 2002
    Location
    SouthEast NC ICW & Piedmont Foothills
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    Operating Sequence COOLING, UNITS WITHOUT ECONOMIZER — When thermostat calls for cooling,terminals G andY1areenergized. The indoor-fan contactor (IFC) and compressor contactor are energized and indoor-fan motor, compressor, and outdoor fan starts. The outdoor fan motor runs continuously while unit is cooling.
    It`s better to be silent and thought the fool; than speak and remove all doubt.

  9. #9
    Join Date
    Jan 2010
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    Quote Originally Posted by 71CHOPS View Post
    sounds like you have something else going on. a 3 minute delay would more likely be on a low pressure switch bypass before it would be on a blower delay.

    someone may have changed the timer and put in the wrong one.
    There's a delay but probably the wrong one. Should be a delay on break vs make.
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  10. #10
    Join Date
    Nov 2018
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    Thread Starter
    Hi Guys.

    I was able to post the wiring diagram to the unit here. It definitely seems like something is not operation properly after reading your posts. I am trying to figure out the wiring diagram here.

    So as described above the unit should not have a time delay on make but a 30 second time delay on break. In the wiring diagram it shows power going to the ICG board from G on the connection board. My question is does the fan Logic determine when the fan runs? I notice on the J2 line on the ICG board there is a IFO black wire going to the IFC coil. If this is the case what are the BM contacts used for on the IGC board?

    thanks



  11. #11
    Join Date
    May 2018
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    VA/DC
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    carrier doesn't have a fan delay on in cooling, just heating

  12. #12
    Join Date
    Nov 2018
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    Thread Starter
    Quote Originally Posted by Cool breeze 38 View Post
    carrier doesn't have a fan delay on in cooling, just heating
    According to the manual there is a 30 second delay on break for cooling.

  13. #13
    Join Date
    Jul 2007
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    Quote Originally Posted by Noname81 View Post
    I notice on the J2 line on the ICG board there is a IFO black wire going to the IFC coil. If this is the case what are the BM contacts used for on the IGC board?
    The single phase Indoor Fan Motors (IFM) in this model line, use the “BM” terminal to energize L1 on the motor, and do not use an Indoor Fan Contactor (IFC).
    Instead of learning the tricks of the trade, learn the trade.

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