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  1. #1
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    Nov 2018
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    Hermetic Compressor Motor Issue

    Forgive me if I am in the wrong area, but the compressor is a motor and this is where I am having my issues. I'm not an A/C technician, but I am knowledgeable in electrical/electrical safety. So I guess you could call this DIY.

    It's an older Cruisair chiller a/c unit with a reverse flow valve for heat. This is installed on a 32 foot sailboat. The customer complaint was a/c was tripping breaker when turned on. When I arrived on site the marina dock power breaker would immediately trip (GFCI installed) when the boat a/c breaker was turned on, great. Figured that out. Looked like someone had been in there prior to me messing around and had the neutral wired to the ground strip. This may or may not have been the cause of the failed controller board as well.

    After those issues were corrected the unit powered up. Electronic display and blower motor works. However, when heat OR cool is selected and the compressor tries to cycle, the marina breaker trips.

    The hermetic compressor has a start, run and common. It also has a start and run capacitor as most do. I performed a resistance test on the compressor itself and it read less than 8 ohms on the start and 10 on the run. Knowing this, I replaced the start capacitor, but the issue was still present. I know that compressors can test good, but still be locked up. I read online that switching the start and run connections at the compressor can cause the compressor to run in reverse and free it up, but only run for a short period of time. I performed this and the compressor seems like it turns on (soft humming). The water pump turns on as well. Switched it back and it immediately tripped the marina breaker when the compressor went to activate. Rechecked the compressor and resistance was unchanged. I checked all of the wiring related to the compressor and all other wiring using the factory diagram and everything looks correct.

    Has anyone had any experience with this? A compressor tripping in only one direction? I have my suspicions that switching the start and run connections at the motor actually switched the direction of the rotation, because in my mind this would only switch the duty of the start and run capacitors (start capacitor on the run winding and run on the start winding). If that's correct, is that indicative of a failed start winding?

    Again I am not an HVAC technician. I am only trying to help a neighbor. I am looking for assistance, not opinions. Thank you!

  2. #2
    Join Date
    Mar 2015
    Location
    Hamersville, Ohio
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    Ryan,

    You are tripping the "Marina Breaker" (GFI), but not the "On-board Breaker"?

    What is the Amp Rating of each of these Breakers, & how many Amps are read at the "on-board Breaker" when the "Marina Breaker" kicks?

    "the compressor seems like it turns on (soft humming)"


    What's the Amp draw when it "Hums"?

    Matter of fact, ... What's the MD.# & Serial #?
    Hos 4:6 My people are destroyed for lack of knowledge. Because you have rejected knowledge, I will also reject you, that you may be no priest to me. Because you have forgotten your God’s law, I will also forget your children.


    "You've got to Stand for Something or You'll fall for anything" (A. Tippin)


    We are on a "Man-made Highway to Hell", Our so called "Leaders", Political & Religious, are encouraging The Mushroom like Sheeple to go faster.

    (AC-DC Lyrics)

  3. #3
    Join Date
    Nov 2018
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    Thread Starter
    Quote Originally Posted by DavidDeBord View Post
    Ryan,

    You are tripping the "Marina Breaker" (GFI), but not the "On-board Breaker"?

    What is the Amp Rating of each of these Breakers, & how many Amps are read at the "on-board Breaker" when the "Marina Breaker" kicks?

    "the compressor seems like it turns on (soft humming)"


    What's the Amp draw when it "Hums"?

    Matter of fact, ... What's the MD.# & Serial #?
    Correct. Tripping the marina breaker, but not the on-board breaker. The marina breaker is a 30amp, the boat breaker is also a 30amp.

    I acquired an amp clamp and I am going to perform an amperage test tonight/tomorrow morning. Both with it connected like the diagrams states and "reversed" (when humming).

    I can also post the model and serial numbers tonight/tomorrow morning.

  4. #4
    Join Date
    Mar 2015
    Location
    Hamersville, Ohio
    Posts
    3,893
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    Quote Originally Posted by Ryan Babros View Post
    Correct. Tripping the marina breaker, but not the on-board breaker. The marina breaker is a 30amp, the boat breaker is also a 30amp.

    I acquired an amp clamp and I am going to perform an amperage test tonight/tomorrow morning. Both with it connected like the diagrams states and "reversed" (when humming).

    I can also post the model and serial numbers tonight/tomorrow morning.
    Hos 4:6 My people are destroyed for lack of knowledge. Because you have rejected knowledge, I will also reject you, that you may be no priest to me. Because you have forgotten your God’s law, I will also forget your children.


    "You've got to Stand for Something or You'll fall for anything" (A. Tippin)


    We are on a "Man-made Highway to Hell", Our so called "Leaders", Political & Religious, are encouraging The Mushroom like Sheeple to go faster.

    (AC-DC Lyrics)

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