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  1. #1
    Join Date
    Oct 2008

    Hmm Help Trane CGACC70 low oil

    hello to everyone! I have a Trane chiller model cgacc70 that I have low oil pressure. Compressor was replaced two years ago. this past summer expansion valve was stuck and solenoid valve was sticking. I installed these items and still having a low oil pressure issue. Read the Trane manual says chiller should have 20 to 30 psi pressure above suction. Do these particular chillers have an oil screen inside the compressor? My oil pressure when the temp is warm outside is only 12 split between the suction and oil pressure. oil in sight glass is half way up fully loaded but has foam. I know foam is not good on any compressor. any ideas? oh yes at start up when I am running unloaded suction pressure is anywhere from 90 - 100 and stays then gradually starts to come down but compressor trips before it will fully load. seems like I do not have this issue in the mornings when it is cool and I do not have all 3 fans staged in.

  2. #2
    Join Date
    Dec 2009
    Fort Worth, Texas
    flooding, broken valves, unloaded to long, faulty hydrolic assembly, what you need to do is fully load machine and take sh and sc also pressures, amp draw and submit them so we can give you a valid answere. i would guess your flooding if your oil is foaming up.

  3. #3
    Join Date
    Aug 2010
    Middle GA
    There is an oil screen in the pickup tube in the compressor. Where are you reading suction pressure from? there should be a suction port on the back side of the compressor. I would try and get on that so you can read actual crankcase pressure. It may also be a stopped up suction screen in the suction line to compressor connection.

  4. #4
    Join Date
    Aug 2006
    Mixing oil and fire with a big spoon.
    do NOT read the compressor suction pressure for your low side. take the system down, recover and crap, add a schrader tee where the oil AND the low side of the pressure switch are located, evacuate and crap and then take readings from those points....this is what the oil pressure switch is seeing. when it comes to sensors (electronic or electro-mechanical) i prefer to 'see' exactly what they are seeing.

    there is a suction screen on the inlet of the oil pick up tube. if it is clogged, you may have a toasted compressor anyway (what is all of a sudden clogging it?).

    what compressor model do you have anyway? my guess is a CRHR350. this compressor oil pressure safety switch is set to trip at about 15 psid and set at 20 psid. typical running pressure differentials are 23-32 on an 'R' model.

    are you using 1 gage or 2 different gages when measuring oil pressure differential? are you measuring oil pressure or oil pressure differential?
    "If you pull one more stunt like you just pulled with Tommy, you won't have to get on a plane because I will personally kick your ass from here to Korea!" - Best of the Best

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