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  1. #1
    8lien's Avatar
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    Install VFD's on Package unit (newbe)



    Hi, I have a question? I can install a VFD on the blower of the roof top package Unit? If yes what do i do with the refrigerant? it will ice up the coil write?
    I heart that i can fix this installing a solenoid valves on the refrigerant lines and bypass the evaporator. This is thrue?



  2. #2
    Brian_UK's Avatar
    Brian_UK is offline Moderator I am starting to push the Mods: of RE Site Moderator : and general nice guy
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    Re: Install VFD's on Package unit (newbe)

    What is it that you are trying to acheive by fitting the VFD and why ?
    Brian - Newton Abbot, Devon, UK
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  3. #3
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    Re: Install VFD's on Package unit (newbe)

    Quote Originally Posted by 8lien View Post
    Hi, I have a question? I can install a VFD on the blower of the roof top package Unit? If yes what do i do with the refrigerant? it will ice up the coil write?
    I heart that i can fix this installing a solenoid valves on the refrigerant lines and bypass the evaporator. This is thrue?
    the only time i have seen a VFD used on the EVAP-blower is in VAV application, this is to maintain the static pressure in the duct and keep it from overpressurized the duck. as for installing a HOTGAS bypass, what is the point. You will be waisting energy.
    As you VFD ramps down you will have to cycle you compressors to keep the coil from freezing.

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    Re: Install VFD's on Package unit (newbe)

    Rather have one on the compressor which can maintain a constant suction pressure . It will enhance compressor life & save you energ etc

  5. #5
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    Re: Install VFD's on Package unit (newbe)

    Packaged unit evaporator fan itself will be 1 to 3 HP depending on the size and VFD for such application is not economical.
    Even where VFD are used for compressors it is advantageous only when there is wide variation in wet bulb temperature for water cooled chillers.
    No doubt VFD will save energy but Life Cycle cost need to be assessed as Operation cost alone is to the tune of 55 to 65%.Logically for higher size motors say multiple AHU's having VFD will save lot of energy.

  6. #6
    8lien's Avatar
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    Re: Install VFD's on Package unit (newbe)

    Thanks for the fast response if I have another question I will ask you guys.

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