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  1. #1
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    Variable Amperage And Cold Liquid line



    Hi
    I have an A/c unit with scroll copmpressor.
    problem is: the liquid line specialy after sight glass is cold ( near of TXV is colder) and when compressor is started the amperage become High and variable.

    i read an article that said if there is a restriction, the amperage must be low because of starved Evap and low suction pressure.

    whats your idea?



  2. #2
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    Re: Variable Amperage And Cold Liquid line

    Replace filter drier

  3. #3
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    Re: Variable Amperage And Cold Liquid line

    i did but the problem is not solved

  4. #4
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    Re: Variable Amperage And Cold Liquid line

    unloaded compressor amperage is 13
    loaded is between 30-50 !!!
    seems there is a restriction such as oil in pipes
    do you agree?

  5. #5
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    Re: Variable Amperage And Cold Liquid line

    What is the compressor nameplate running amps?

    If it is running way above the nameplate FLC then it sounds like your compressor is goosed. A blockage will not make the compressor draw that sort of amps.

  6. #6
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    Re: Variable Amperage And Cold Liquid line

    copeland scroll ( nominal 30 A )

    so, you think Comp. is down.

  7. #7
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    Re: Variable Amperage And Cold Liquid line

    Megger it to find out.

  8. #8
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    Re: Variable Amperage And Cold Liquid line

    Suction & discharge pressures at the same time would also be helpful.

  9. #9
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    Re: Variable Amperage And Cold Liquid line

    Discharge 225 psi
    Suction 45 psi
    Amperage between 35 - 50 ( copeland scroll / nominal 30 A)
    Unloaded: 13 A
    And the liquid line is cold specially after sight glass
    Last edited by hsn157134; 02-10-2014 at 09:50 AM.

  10. #10
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    Re: Variable Amperage And Cold Liquid line

    Was your indoor unit running as heat pump or cooling?
    Have you checked compressor winding?
    After sight glass should be warm subcooled liquid. If its cold that could be a sign short of refrigerant. If you refer to PH chart you will know the compressor will always pull too many amps when its under charged.

  11. #11
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    Re: Variable Amperage And Cold Liquid line

    its a cooling unit and the compressor winding is normal.
    there was problem when the charge was complete.
    plus, the sight glass indicator shows the system is wet.
    after a vacume, the problem was too.
    ( sorry for bad English)

  12. #12
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    Re: Variable Amperage And Cold Liquid line

    Measure the voltage going to the compressor when the compressor is loaded. Iranian supply should be 230 volts at 50 Hertz using single phase. (Source: Google search.)
    Are you using R22? Have you tested the Capacitors?
    The new filter/Drier will help sort the moisture problem but not the compressor.
    To the optimist, the glass is half full. To the pessimist, the glass is half empty.

  13. #13
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    Re: Variable Amperage And Cold Liquid line

    Drawing 30 Amps on any single electrical item at 240 Volts/ 50 HZ is beyond Australian standards. Drawing 30 amps on one phase of a 3 phase compressor is common in industrial applications.
    To the optimist, the glass is half full. To the pessimist, the glass is half empty.

  14. #14
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    Re: Variable Amperage And Cold Liquid line

    Its a 30 tones A/C with r22
    And I changed the drier but the problem is on.
    So I take the comp and sent for Seller to check it
    And I clean all of system.
    But I like to know whats the reason of problem.

  15. #15
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    Re: Variable Amperage And Cold Liquid line

    What voltage system is this thing operating on?

    (1) 30 Amp Scroll on a 30 Ton Chiller for (1) machine comes close to corresponding with a 460V 3 Ph 60 Hz arrangement....On 230 V 50 HZ the current should be a lot higher. What does the entire compressor nameplate read in terms of Voltages and Current?

  16. #16
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    Re: Variable Amperage And Cold Liquid line

    Quote Originally Posted by sterl View Post
    What voltage system is this thing operating on?

    (1) 30 Amp Scroll on a 30 Ton Chiller for (1) machine comes close to corresponding with a 460V 3 Ph 60 Hz arrangement....On 230 V 50 HZ the current should be a lot higher. What does the entire compressor nameplate read in terms of Voltages and Current?
    my mistake.
    15 tone is true and nameplate is 380V/ nominal A: 30

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