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Compressor losing oil

Empire_2
Empire_2 Member Posts: 2,343
in A-C, Heat Pumps & Refrigeration
> I'm currently having problems with Mquay rooftop <BR>
> package unit. The compressor keeps losing oil. <BR>
> I've checked the crankcase heater, it's working <BR>
> fine. I put about a QT of oil in every two weeks. <BR>
> Pressures are good, unit runs fine, and there's <BR>
> no foam in the sight glass. Where could the oil <BR>
> be going, eventually it has to come back? Please <BR>
> help. <BR>
<BR>
> I'm currently having problems with Mquay rooftop <BR>
> package unit. The compressor keeps losing oil. <BR>
> I've checked the crankcase heater, it's working <BR>
> fine. I put about a QT of oil in every two weeks. <BR>
> Pressures are good, unit runs fine, and there's <BR>
> no foam in the sight glass. Where could the oil <BR>
> be going, eventually it has to come back? Please <BR>
> help. <BR>
<BR>
When you first checked the sight glass what was the oil level? How many qts have you injected since then?

Comments

  • Rookie_5
    Rookie_5 Member Posts: 6


    I'm currently having problems with Mquay rooftop package unit. The compressor keeps losing oil. I've checked the crankcase heater, it's working fine. I put about a QT of oil in every two weeks. Pressures are good, unit runs fine, and there's no foam in the sight glass. Where could the oil be going, eventually it has to come back? Please help.
  • Empire_2
    Empire_2 Member Posts: 2,343
    Question

    What was the level when you first checked the RTU? How many qts have been injected since then?
  • Eugene Silberstein 3
    Eugene Silberstein 3 Member Posts: 1,380
    Some things to consider

    Oil does not evaporate so if you are indeed losing oil, it must be leaking out. A couple of questins for you...

    How is the refrigerant charge?

    What metering/expansion device does the sytem have?

    How did you determine that the compressor needed oil?

    What is the evaporator superheat?

    What is the condenser subcooling?
  • Rookie_5
    Rookie_5 Member Posts: 6


    I don't remember all my numbers off hand, but I'm sure it was nothing too alarming. I will record and write down all my temps and pressures and post them Monday.
  • Marty
    Marty Member Posts: 109
    evap

    Odds are its hanging around in the evap coil patiently
    waiting for enough to collect and come back all at once to its happy home in the compressor. Might want to take a long hard look at any low ambient and capacity controls etc.
  • Empire_2
    Empire_2 Member Posts: 2,343
    Rookie

    I was just currious, not busten Balls when I asked you your observations of the oil adding. Assuming you have a Semi-hermetic,... As Eugene stated if there is a leak it has to come out somewhere. How large is the RTU?, any solenoid valves staging the unit/ any unloader capabilities?
  • rick_36
    rick_36 Member Posts: 19


    Also check assuming it is a semi hermectic check the oil pressure while it is running. also check for the above mentioned topics, What kind of refrigerant are you using.
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