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  1. #1

    Carrier HH84AA009 fan control board vs. ICM275

    The replacement bpard for the HH84AA009 is supposed to be the ICM 275

    the icm275 has newer compact relays and some operational differences, to quote the manual:

    "Operational Differences and Added Features
    The following is a description of the slight operational differences and added features. Refer to ICM275 Component Layout (Page 3) for location of control center components.
    Operation with new blower and humidifier relays:
    The previous design control centers used a SPST-NC or DPST-NC heating fan relay (HFR of E2) and a DPDT cooling fan relay (CFR or 2F) for blower and humidifier terminal operation. This new control center uses a SPST-NO blower relay (BLWR) and a SPDT blower speed change relay (hi/lo) for blower operation, and a SPST-NO humidifier relay.
    1. The low-speed blower will not operate on a transformer failure as on previous designs.
    2. If JW1 jumper is cut between R and GH terminals, a constant low-speed blower will occur without any thermostat inputs to the control center. A GC or Y signal to the control center will not bring on the hi-speed blower for cooling operation. JW1 jumper must not be cut on cooling applications.
    3. The humidifier H terminal is energized with low-speed blower operation. In cooling operation, the humidistat and humidifier water supply should be turned off to ensure the humidifier does not operate."

    are there any wiring modifications needed?

    after replacing the board, blower works just fine, when stat is set to "on"
    the cooling will work fine as long as the fan setting on the stat is set to "on"

    The problem is that when the stat is set to auto, the blower will go on, and then after a minute or so when the cooling kicks in, the unit will "reset" and try many times what seems to be a false start.

    any suggestions?
    anyone have experience with this newer board as a replacement of the originals?

  2. #2
    Join Date
    Jan 2004
    Sorry, this is not a DIY site. So you won't get any help. Please read the rules that you.

    If your in the trade. Pleas read the rules. No technical discussions are done in the open resi forums.
    Get your post count up to 15 and you can apply for pro membership, and get access to the pro forums where technicals discussions are allowed.
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    How many times must one fix something before it is fixed?

  3. #3
    As said this is not a DIY site.

    Go back there and provide info asked for.

  4. #4


    not exactly a DIY, I am certified and work in the refrigeration business.

    I have not dealt with HVAC per se, in over 20 yrs, that is why if you see I was MAINLY asking if anyone knows of any significant differences between the old controller board and the new one.


  5. #5
    Carrier model provided does not exist.

    Suspect R18 needs to be cut.

    Refrigeration is low pressure a/c

    A/C is high pressure refrigeration.

    Basic cycle is basic cycle.

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