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  1. #1
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    I have inherited a 30gx ( tonnage??? 4 compressor) that has started to randomly trip low oil level alarms on circuit B repeatedly since the out door temp started falling.

    I added some oil after recovering it back as per manual and it is still doing it.

    I do know that the minimum load kit and the oil re-route kit for the comps has been recently installed back in the summer (July)

    I have checked the level and it appears OK.

    The oil heaters are a-OK

    The machine appears to be operating normal when I have checked it and logged it out. All the numbers look OK.
    I did change the loading from staged to equal as I would notice B ran a lot at minimum load and felt this may have been part of the problem.

    This is a process chiller not comfort cooling.

    Has anyone had any problems with the oil level switches ,the kind that screw in the bottom of the separator?

    Any ideas would be appreciated.
    mikeacman

  2. #2
    Join Date
    Oct 2006
    Posts
    1
    What is the chilled water set point?
    If the Chilled water set point is too high the unit will short cycle and cause the oil to migrate

  3. #3
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    48 degrees F, It doesn't short cycle but another tech set it up for A to lead so B runs at very low load for extended periods.

    I do not like this and am going back today to give it a good going over again and look really hard at the config. The tech that was working on it is now in IRAQ so I can't really quiz him on anything but , I do know it has always been a problem child.
    mikeacman

  4. #4
    Join Date
    Jul 2005
    Posts
    134
    Did you ever learn the cause of the low oil alarms?

  5. #5
    Join Date
    Apr 2007
    Location
    uk
    Posts
    181

    30GX low oil level alarms

    If you are sure the oil level is ok then the problem is likely the oil level switch connections or the oil level switch.

  6. #6
    Join Date
    Sep 2007
    Location
    SF Bay Area
    Posts
    130
    Coming late the party. Carrier's fix for low oil faults is usually to add more oil until the problem goes away, which can result in even more problems. If your process load is steady, and condenser press/temp control is good, there shouldn't be a problem.

    Continuous low ambient operation and short-cycling are certainly possibilities, but here are two more I've seen to consider:

    #1 Bad oil separator - Observe the sight glass before the EXV (or the Economizer), if you see white foam and the liquid line is cool, you've got too much oil carryover through the condenser. This is an indication of a torn or collapsed arresting screen in the oil separator. The only fix for this is to replace the separator (sorry).

    #2 Stuck oil solenoid relay - An oil solenoid valve that is energized or stuck open on a non-operating comp will allow oil to pass directly through that comp and into the evaporator while the other comp in the circuit is running. During low-load conditions more oil will pass into the evaporator through the oil valve that will be returned to the separator, resulting in low oil levels.

    There are two causes: 1) the valve is simply stuck open, or, 2) The oil solenoid relay on the CPM (Comp protection module) is burned closed, continuously energizing the oil solenoid valve.

    While the chiller is off, check the oil solenoids on all comps. If any comp has an energized oil solenoid, that most likely means you've got a bad oil relay on that comp's CPM.

    The CPMs are found in the control panel, they are the two 'exposed' circuit boards (approx 5"x10"). The 'A1' & 'A2' comp connections will either be at the top or the left side of each CPM board respectively, depending if they're mounted vertically or horizontally. The 'B' comp connections will be at the bottom or right side of each board.

    Verify proper oil solenoid operation by enabling manual operation and cycling the solenoid.

    If you change CPMs, don't forget to move the configuration header(s) from the old board to the new.

  7. #7
    Join Date
    Sep 2007
    Location
    Bay Area California
    Posts
    321
    nice post heatxfer...

    i have found bad oil level switchs and tried to dance aound it before condemning...

    also consider your base load... equal loading may not be a good idea based on low ambient considerations...

    good luck

  8. #8
    Join Date
    Feb 2007
    Location
    charleston sc
    Posts
    3
    Also check delta P of internal and external oil filters, I have found that you will get different alarms related to oil as they become restricted. It wont always give low oil pressure alarms

  9. #9
    Join Date
    Mar 2005
    Posts
    664
    was going to post this a couple months ago for some input from carrier pros

    , had a crazy high oild diff alarm on 30gx which has since gone to quote , odd building/customer , im not that familiar w these chillers , but external and internal oil filters checked out 100% , and oil trnsducer was changed out new, this is ckt a2 which is common for ckt a1

    1, basically this fault was constant , but after a few trips and several
    runs i finally found prodialog display going off the roof w diff on a2 reading something like 100psi diff which was 0 or close too , also when this would shoot up all of a sudden would find ckt a1 which ran fine w no oil diff alrams whatsoever shoot up for a few secs to high inaccurate number before a2 running would trip out then a1 would resettle to correct number, hard to catch this especially scrolling thos dialog keypads , i was leaning torwards processor , but didnt know about this calibration aspect , but thing w that is reads accurate at times , any thoughts ? regads stan
    Keep it simple to keep it cool!

  10. #10
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,709
    Quote Originally Posted by stanbyyourword View Post
    was going to post this a couple months ago for some input from carrier pros

    , had a crazy high oild diff alarm on 30gx which has since gone to quote , odd building/customer , im not that familiar w these chillers , but external and internal oil filters checked out 100% , and oil trnsducer was changed out new, this is ckt a2 which is common for ckt a1

    1, basically this fault was constant , but after a few trips and several
    runs i finally found prodialog display going off the roof w diff on a2 reading something like 100psi diff which was 0 or close too , also when this would shoot up all of a sudden would find ckt a1 which ran fine w no oil diff alrams whatsoever shoot up for a few secs to high inaccurate number before a2 running would trip out then a1 would resettle to correct number, hard to catch this especially scrolling thos dialog keypads , i was leaning torwards processor , but didnt know about this calibration aspect , but thing w that is reads accurate at times , any thoughts ? regads stan
    Have you tried any die-electric grease on the op transducer?Does it happen when moisture is present?
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  11. #11
    Join Date
    Mar 2005
    Posts
    664
    nope absolutely dry days and new transducer
    Keep it simple to keep it cool!

  12. #12
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,709
    Do you ever et to see it fluctuate with your guage and actually see the pressure hunt around?
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  13. #13
    Join Date
    Mar 2005
    Posts
    664
    nope steady, and good sound cable connections also , maybe ill repost new thread as not to highjack this oiginal , see you there! regards stan
    Keep it simple to keep it cool!

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