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  1. #1
    Join Date
    Jan 2005
    Location
    Veterans Home Yaphank, NY
    Posts
    2,309

    Red face Pump-out vs Pump-down

    Sorry to seem stupid, but need a good full description so as to explain to group of "Newbies" Thanks in advance
    RAM Teaching Tomorrows Technicians Today.

  2. #2
    there are some real good farely recent threads about this one. if ya put this in the search it'll unearth at least one I can remember.

  3. #3
    Join Date
    Jan 2007
    Location
    Sidney, OH
    Posts
    35
    Pump-out: Also known as a "one time pump out", is conducted by closing a solenoid in the liquid line (or in some refrigerated cases with defrost it is in the suction line) while the compressor is still running, all of the refrigerant in the system downstream of the soleniod is removed. The compressor is shutdown by a low pressure control, and remains off until the next call for cooling which opens the solenoid valve and closes the contacts for the compressor. Thus the compressor pumps out the system after each running cycle, then remains off until the next call for cooling.

    Pump-down: Also known as "continuous pump down", is conducted exactly the same way as pump-out with the exception that the call for cooling ONLY controls the solenoid. Thus, during a normal running cycle, when demand is met, the solenoid is closed. The compressor pumps out all of the refrigerant downstream of the solenoid then shuts of on a low pressure control. the difference being that the compressor is allowed to restart any time the low pressure control makes, thus keeping the suction side of the system pumped down continuously. This usually comes into play if there is a leaking pump down solenoid.

    Copeland likes to see a continuous pumpdown used.

    the purpose of both of these is to minimize the effects of migration, which can result in a flooded start on the next startup.
    Andrew Joines
    Joshua 1:9
    Emerson Climate Technologies
    Training Specialist

    01 out of 10 people don't understand binary.

    "Size matters not."
    -Yoda, Jedi Master

  4. #4
    Join Date
    Jan 2005
    Location
    Veterans Home Yaphank, NY
    Posts
    2,309

    Smile

    Quote Originally Posted by StealthSuitStan View Post
    Pump-out: Also known as a "one time pump out", is conducted by closing a solenoid in the liquid line (or in some refrigerated cases with defrost it is in the suction line) while the compressor is still running, all of the refrigerant in the system downstream of the soleniod is removed. The compressor is shutdown by a low pressure control, and remains off until the next call for cooling which opens the solenoid valve and closes the contacts for the compressor. Thus the compressor pumps out the system after each running cycle, then remains off until the next call for cooling.

    Pump-down: Also known as "continuous pump down", is conducted exactly the same way as pump-out with the exception that the call for cooling ONLY controls the solenoid. Thus, during a normal running cycle, when demand is met, the solenoid is closed. The compressor pumps out all of the refrigerant downstream of the solenoid then shuts of on a low pressure control. the difference being that the compressor is allowed to restart any time the low pressure control makes, thus keeping the suction side of the system pumped down continuously. This usually comes into play if there is a leaking pump down solenoid.

    Copeland likes to see a continuous pumpdown used.

    the purpose of both of these is to minimize the effects of migration, which can result in a flooded start on the next startup.
    My deepest thanks to you. When I teach, I strive to give the best information possible so that the industry will continue to have the best qualified individuals. Bless you.
    RAM Teaching Tomorrows Technicians Today.

  5. #5
    Join Date
    Feb 2007
    Posts
    35

    Talking

    good info

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