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  1. #1
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    hot liquid and suction lines



    probably an easy answer but i cant see why both the liquid and suction lines are hot.
    this is on a 9kw highwall split unit, air off 47 air on 20
    500psi on heat
    but not really performing well ,as in it doest kick up to high fan, and no its not oversized.

    any ideas



  2. #2
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    Re: hot liquid and suction lines

    U sure your compressor is pumping?

  3. #3
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    Re: hot liquid and suction lines

    yes hence 500psi

  4. #4
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    Re: hot liquid and suction lines

    also sounds like is boiling in the indoor unit

  5. #5
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    Re: hot liquid and suction lines

    Filters and coil clean? Fan blade/blower wheel clean?

    Where are you taking your temperature measurements? Just wondering as the interconecting pipe work will be hot during heating mode. I expect the liquid line is in fact an expansion line.

  6. #6
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    Re: hot liquid and suction lines

    500 psi sounds like you use air as refrigerant.

    Evacuate and recharge.

    Check that 4 way valve performs OK.

  7. #7
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    Re: hot liquid and suction lines

    Quote Originally Posted by chemi-cool View Post
    500 psi sounds like you use air as refrigerant.

    Evacuate and recharge.

    Check that 4 way valve performs OK.
    Like Chemi says thats a high pressure, what refrigerant is it using? I hope the system is on R410A with pressures like that!

  8. #8
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    Re: hot liquid and suction lines

    Quote Originally Posted by djs View Post
    probably an easy answer but i cant see why both the liquid and suction lines are hot.
    this is on a 9kw highwall split unit, air off 47 air on 20
    500psi on heat
    but not really performing well ,as in it doest kick up to high fan, and no its not oversized.

    any ideas
    What is unit make and model? What is outdoor temperature?

    On high wall split system in heating mode both lines are part of condenser and therefore both should be hot.
    One hotter than another (one little below of compressor discharge temperature and other little below condenser saturation temperature).

    Recover and weigh charge. It is best to evaluate performance by observing temperature difference and air flow before recovery and evacuation.

    Δt of 27°C at indoor heat exchanger is sligtly high and could point to problem with insufficient air flow. Maybe fan speed is not on high, or filter and heat exchanger is dirty, or fan condenser is faulty, etc...

    If you have lines longer than unit is charged for, you need to calculate additional amount of refrigerant and see if it is added or not.
    Than charge correct amount and see if unit is performing OK by measuring air flow and air in and out temperature difference.
    Last edited by nike123; 10-08-2010 at 05:40 PM.

  9. #9
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    Re: hot liquid and suction lines

    Quote Originally Posted by chemi-cool View Post
    500 psi sounds like you use air as refrigerant.

    Evacuate and recharge.

    Check that 4 way valve performs OK.
    Chemi, it could be R410a.
    500 PSI is 34.5 Bar which is 57°C CST which looks to me perfectly OK.

  10. #10
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    Re: hot liquid and suction lines

    You can be on the right side, lets wait and see.

    Meanwhile you can enjoy the Chinese drivers....

    http://www.youtube.com/watch_popup?v=QESfEd180rQ

  11. #11
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    Re: hot liquid and suction lines

    Quote Originally Posted by chemi-cool View Post
    Meanwhile you can enjoy the Chinese drivers....
    At least they are driving pretty slow.

  12. #12
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    Re: hot liquid and suction lines

    thanks for all replys ,it is on 410A so i expect around 500psi, the pipe is only 3mtrs so the supplied charge should be ok.
    imthinking i might move the themostat from the unit to the opposite wall.
    the unit is a mitsubishi ge80

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