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  1. #1
    Join Date
    Feb 2008
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    Variable speed fan wiring/settings questions ...

    System: VisionPRO IAQ t-stats, Trane XL14c Dual Fuel, Honeywell HZ432 TrueZONE Panel

    - The install instructions for the HZ432 say to wire the AHU to the DS/BK terminal. I've checked and nothing is connected to it. Everything else seems to be connected properly. I plan on calling my tech, but for my own general knowledge - what wire from the Trane unit should be connected to the DS/BK jumper?

    - The install instructions for the Trane XL14c mention dip switches on the ECM Fan Control. It says these 8 dip switches allow the variable fan settings to be changed, and to see the Airflow Table and the Blower Performance Table in the SERVICE FACTS for more info. I cannot find these tables or SERVICE FACTS. Anyone know where to find it? Anyone have more info on these dip switches?

    - The Trane unit has the Comfort-R with the ramp-up fan speed. The HZ432 will also reduce fan speed by 80% when only one zone is calling. Question - if both these option are enabled, will the Trane unit still ramp-up even when it's being reduced to 80% by the panel?

    - Where exactly is Comfort-R enabled/disabled on the unit?

    TIA

  2. #2
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    Jun 2007
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    Round Rock
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    3,619
    The only thing I will tell you is that Trane does not have a dehumidication terminal. It will overcool up to 3 degrees to achieve the desired setpoint. Other than that, put the door back on the unit and wait until the tech shows up. You can do 1 of 2 things. Either really screw something up that will take the guy a while to undo what you have done, such as frying a circuit board, motor, transformer and the least desirable is to hurt yourself.

  3. #3
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    Jul 2008
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    Alabama
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    Quote Originally Posted by richmod View Post
    System: VisionPRO IAQ t-stats, Trane XL14c Dual Fuel, Honeywell HZ432 TrueZONE Panel

    - The install instructions for the HZ432 say to wire the AHU to the DS/BK terminal. I've checked and nothing is connected to it. Everything else seems to be connected properly. I plan on calling my tech, but for my own general knowledge - what wire from the Trane unit should be connected to the DS/BK jumper?

    - The install instructions for the Trane XL14c mention dip switches on the ECM Fan Control. It says these 8 dip switches allow the variable fan settings to be changed, and to see the Airflow Table and the Blower Performance Table in the SERVICE FACTS for more info. I cannot find these tables or SERVICE FACTS. Anyone know where to find it? Anyone have more info on these dip switches?

    - The Trane unit has the Comfort-R with the ramp-up fan speed. The HZ432 will also reduce fan speed by 80% when only one zone is calling. Question - if both these option are enabled, will the Trane unit still ramp-up even when it's being reduced to 80% by the panel?

    - Where exactly is Comfort-R enabled/disabled on the unit?

    TIA

    IF your installing company knows what they are doing , it's right.

    DS/BK is for dehumidification purposes. On older Trane ahu this terminal had to be wired to enable variable speed options. On newer units it is used in conjunction with (de)humidistats.

    Don't mess with those dips, they set air flow, etc... They tell the blower how to respond.

    The HZ432 zone board can't slow down the blower no matter how many zones are calling. It can prevent 2nd stage on only one zone call.

    Leave it alone and let the pro work on it before you screw it up!!
    Last edited by superd77; 07-14-2008 at 12:08 AM. Reason: spelling

  4. #4
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    Quote Originally Posted by bmathews View Post
    The only thing I will tell you is that Trane does not have a dehumidication terminal. It will overcool up to 3 degrees to achieve the desired setpoint. Other than that, put the door back on the unit and wait until the tech shows up. You can do 1 of 2 things. Either really screw something up that will take the guy a while to undo what you have done, such as frying a circuit board, motor, transformer and the least desirable is to hurt yourself.
    Whats the Bk terminal for then.
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  5. #5
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    Feb 2008
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    Quote Originally Posted by bmathews View Post
    The only thing I will tell you is that Trane does not have a dehumidication terminal. It will overcool up to 3 degrees to achieve the desired setpoint. Other than that, put the door back on the unit and wait until the tech shows up. You can do 1 of 2 things. Either really screw something up that will take the guy a while to undo what you have done, such as frying a circuit board, motor, transformer and the least desirable is to hurt yourself.
    I didn't open or mess with anything. I just looked at it. I think I'm entitled to do that after spending thousands of dollars.

  6. #6
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    Jun 2007
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    Quote Originally Posted by beenthere View Post
    Whats the Bk terminal for then.
    A direct line to Burger King

  7. #7
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    Feb 2008
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    78
    Quote Originally Posted by superd77 View Post

    The HZ432 zone board can't slow down the blower no matter how many zones are calling. It can prevent 2nd stage on only one zone call.
    This is straight from the HX432 install manual:

    "The DS/BK terminal is used with a variable-speed fan. Connect the DS, BK, ODD, or DHUM terminal on the HVAC equipment to this terminal. When 1 zone is calling (or 25% on systems with more than 4 zones) this terminal
    will be de-energized of 24 VAC. This reduces blower speed on most variable speed blowers."

    That is step #6 from the install manual.

    I'm not opening anything, messing with anything, or screwing anything up. I'm simply seeking expert advice on how to wire the variable speed fan, and why it wasn't done in accordance with the install manual.

  8. #8
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    Jan 2004
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    Quote Originally Posted by richmod View Post
    I'm not opening anything, messing with anything, or screwing anything up. I'm simply seeking expert advice on how to wire the variable speed fan, and why it wasn't done in accordance with the install manual.
    We aren't allowed to tell you how to wire it.

    As far as why your installer didn't.
    Many times salesman sell you devices that the installers have no training on. And no idea how to install them.
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  9. #9
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    Round Rock
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    I don't know what you're furnace says in it. But mine says BK/TWIN. I would assume that is to twin a furnace, not for dehumidification. All the ones I've ever worked on say the same thing as well.

  10. #10
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    Lancaster PA
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    And if you don't put 24 volts to it, they blower runs at 80% speed.
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