pumps.,
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Thread: pumps.,

  1. #1
    Join Date
    Jan 2009
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    Talking pumps.,

    question 1 ?
    must the chilled water loop pump and the chiller barrol pump run at the same time., .,because i am thinking that one pushes throught the chiller barrol and the other pushes throught the building loop.,
    what if one failed., would this create strain on the other pump?

    question 2 ??

    assuming that the machine is running fine,. the chiller pump and the loop pump are running <of course> ., and some how the building loop redundent pump was turned on??

    what does this do to the pumps , water circuit., will this mess up flow tremendously??


    and question 3??
    what if there was a building that only had on/off chilled water actuators valves.,not a 3 way., say all system satified .,all valves closed., and pumps DO continue to run,,what happens to the pumps.,.,and would this be a bad design for a chilled water system., i am thinking so.,


    .,AND I FOUND OUT TODAY that even thought u may have 45 * water .,.,but if ur pumps are not moving water ., ass out of gass.,.,lol
    thanks
    no signature blast'em man blast'em
    !!!KILL THE TERRORIST!!!

  2. #2
    Join Date
    Jul 2008
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    #1 - Both pumps need to operate whenever the chiller is running. The primary pump ensures that there is always correct flow through the chiller. The secondary pump pulls chilled water off the primary loop and feeds the building. This system will only work and save energy if 2-way control valves are installed at the air handlers.

    #2 - If the loop pump was shut down during chiller operation the primary pump is not sized to move water through the whole building so you would not pull enough heat out of the building and the chiller would unload and then cycle on temperature.

    #3 - The primary/secondary pump design needs 2-way valves to operate correctly. When the air handler control valves back-off or shut down that will increase the discharge pressure in the secondary loop and the secondary pump will slow down if a VFD is installed or by-pass valve will start to open to relieve the pressure back to the pump suction.
    Effort is the 1st step towards failure.

  3. #3
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    Nice explanation TAC

  4. #4
    Join Date
    Mar 2003
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    7,321
    if you find an engineered systems mag this month, there is about a six page dissertation on this very topic. the answers to your questions, like many topics are not absolute. i have chilled water systems that work differently than the posted answers that do a fine job, it just depends.....

  5. #5
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    Quote Originally Posted by TAC Service View Post
    #1 - Both pumps need to operate whenever the chiller is running. The primary pump ensures that there is always correct flow through the chiller. The secondary pump pulls chilled water off the primary loop and feeds the building. This system will only work and save energy if 2-way control valves are installed at the air handlers.

    #2 - If the loop pump was shut down during chiller operation the primary pump is not sized to move water through the whole building so you would not pull enough heat out of the building and the chiller would unload and then cycle on temperature.

    #3 - The primary/secondary pump design needs 2-way valves to operate correctly. When the air handler control valves back-off or shut down that will increase the discharge pressure in the secondary loop and the secondary pump will slow down if a VFD is installed or by-pass valve will start to open to relieve the pressure back to the pump suction.


    thanks for the info.,

    what is the purpose of turning off the pumps when the chiller is at setpoint?
    no signature blast'em man blast'em
    !!!KILL THE TERRORIST!!!

  6. #6
    Join Date
    Jul 2008
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    Southern California
    Posts
    138
    In most cases the CHW pumps will not shut down on chiller setpoint. The pumps are generally controlled by OSA, RA,etc.
    Effort is the 1st step towards failure.

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