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  1. #1
    Join Date
    Jun 2006
    First I'd like to say great site, I've really learned a ton.

    To start my setup is a 75btu 90% AFUE and 2 ton 12 seer WeatherKing setup. My house is 900 sq ft first floor and 450 sq ft basement, located in Louisville, KY. Which can be pretty Humid in the summer months.

    Before I get into this I'd like to say I do not plan to touch anything or change any settings, this is simply to satisfy my self education urges, as I like to be an informed homeowner.

    After doing some browsing and reading about the blower speeds and CFM needs for A/C and humidity removal, I went and read all the manuals and diagrams for my system.

    What I found is that I have three terminal connections on the control board that lead to a capacitor (I can't recall from memory if capacitor is actually what it is). Terminals are labeled "Heat", "Cool", "M1" (M1 is labeled as being an extra motor setting) each with a large wiring leading to the capacitor. Per the diagram the "M1" leads to the low setting, the "Heat" to the Med, and "Cool" to high.

    My question is in order to lower the speed for cooling would the tech simply swap the "M1" (blue wire) with the "Cool" (black wire), thus making the high setting unused and in turn making the "low" speed setting for "cool"?

    What if the Med motor setting was desired for "heat" and "cool", would the tech then piggyback the wires?

    I appreciate and answers you can give, and as I stated before this is simply to satisfy my curiosity.

  2. #2
    Join Date
    May 2000
    Indianapolis, IN, USA
    If that is the 90RJ07 with 3 ton drive, you'd want low for cool, medium for heat.

  3. #3
    Join Date
    Jun 2006
    Originally posted by BaldLoonie
    If that is the 90RJ07 with 3 ton drive, you'd want low for cool, medium for heat.
    Yes you are correct it is the 90RJ07.

    I also thought that low would have been the setting of choice.

    Am I correct in assuming that the tech will simply swap the "Cool" and "M1" wires to achieve these settings?

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