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Thread: Trane XV80 Furnace 2nd Stage Cooling Wiring Question

  1. #1
    Junior Member

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    Trane XV80 Furnace 2nd Stage Cooling Wiring Question

    I will be installing a new Trane XV80 furnace and 2 stage scroll condenser condenser (no dedicated de-humidifier) this Saturday and reading over the manual has me a bit confused.
    The installation manual for the furnace has conflicting advice regarding wiring the second stage cooling. Page 20 Note 8. Reads, “For two step scroll system use Y for low speed and BK for high speed connection to the LVTB. Place a jumper between R and O and move S5-2 to the OFF position.
    Page 23 of the manual, under note 7 reads "the Y2 terminal from the thermostat must be wired to the Y terminal of the furnace control for proper blower operation during cooling.”

    Just trying to confirm the correct wiring should be thermostat-furnace-condenser should be Y2-BK-Y2 with a jumper at the furnace between R and O with the S5 Dip switch off (S5-2 OFF means de-humidifier = installed). I’m just worried because I thought BK was the proprietary variable speed blower wire that requires a specific Trane thermostat.

    Furnace board has
    YLO Y W W@ R G C O BK/DS/DHUM

    Ecobee
    4TTR7036A1 - XR17 Climate Tough Condenser
    TUD2B080A9V3V - XV80 Furnace
    4TXCB004DS3HC - 3 Ton Coil

  2. #2
    Senior Member

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    They advertise "you can't stop a Trane" but what they don't talk about is that it is even harder to get one going. Trane is in their own universe with strange connections.

    From what I've figured out is that the two methods are for different levels of stage one blower speed. When using the BK there is only a slight reduction in blower speed, maybe 20% as it is really designed for dehumidification. Using YLo goes to a lower blower speed. So find out the compressor specs and go from there.
    Last edited by Stuff; 06-06-2020 at 07:18 AM.

  3. #3
    Junior Member

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    I guess Ill have to take measurements for the airflow to see what its doing when its all put together. The compressor is a 3 ton unit. Runs 70 percent stage 1, 100 stage 2 so a reduction of 20 percent is close. I also have my cfm set to 350 a ton, so on the low side of normal. I need to find out what percentage Ylo runs the fans at. The manual states for a dual compressor setup run Ylo and Y, but for a single scroll 2 stage compressor run Y and BK.

    Last edited by PoppinJ; 06-07-2020 at 08:10 PM.

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