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  1. #1
    Join Date
    Jun 2011
    Location
    Detroit, MI
    Posts
    66

    Carrier 30GX loosing oil

    Hi guys, I've got a bit of an issue I don't fully understand yet. I have a carrier 30GXR249-A-640EL. This client wanted me to take a look at it today while we were there for some other work. What went from half working went to offline- both circuits are failing out on T124 and T125. Ambient today was 100 and chilled water got up pretty warm to 85. I started to familiarize myself with the chiller- first system a was offline. I dind't make any changes to anything- was in observation mode. I sat down to see what the error was about and say that it was the float switch in the oil res was open. The client was insisting that it was out filters being plugged, but after gaining understanding of the error, I dind't aggree with that. As I was sitting there the b circuit tripped on the same lock out. So, I read further in the manual and gained the best understanding I could for the crash course time I had.

    What senarios cause oil loss on these chillers? With what I could understand, it looks like the oil simply comes back with the refrigerant in the suction stream, is this true or is there eductors like Yorks? The chiller is in neglect- B was carpeted over and was running about 220/40 4 degree delta and with A running one comp fully loaded it was about 160/30 with 2 degree delta. I suspect that the a systems are low on refrigerant considering the various spots of oil I saw and the A system evap only at 30 psi with 85 degree water- exv was at 80% I believe. Both sight glasses are bubbling badly.

    My current theory is B is loosing oil from running higher than needed head and slightly undercharged and A seems to be undercharged.

    I dind't go too much farthur with it- wanted to read some more without someone breathing down my neck and hopefully get some experience passed onto me here. Thanks.

  2. #2
    Join Date
    Apr 2012
    Location
    Paper Street Soap Company
    Posts
    2,304
    Carrier screw right ? Air or water source condenser ?

  3. #3
    Join Date
    Jun 2011
    Location
    Detroit, MI
    Posts
    66
    Air cooled, yes has 3 screws

  4. #4
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,702
    Those units have oil seperators the level switch is located at the bottom . You probably need to get a good log of the circuit pressures and temps plus the liquid level of the cooler. Take readings from the navigator. Are the oil stains/leaks large possible oil loss to the system via the ground?
    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.

  5. #5
    Join Date
    Jun 2011
    Location
    Detroit, MI
    Posts
    66
    No, the oil that I see round the leaks is just enough to make it wet and cause it to get dirty...seems to have been like that for a while, no puddles to be seen. When I return I'm planning on doing a few things I've read on this site and some of the proceedures listed in the manual. Really nice to be able to sit and read without worrying about someone looking over my shoulder. The level was maintaining close to setpoint in B but A was off the indicator and the econo was open more than 75% If B is low, it may not be horribly low, but A has my attention. Considering the blanketed coils for B I wondered f there was a high pressure load limitation that the controls put on it- and thinking back, it wouldn't load both stages. after I gave it a quick brush down it loaded both stages. This may explain the B oil loss- running a lon time with partial load.

    Today was just the first visit, so I'll be going back with more ammo. I'm probably going to pull the charge on A and weigh it to verify it after a leak check.

    Thanks for the input guys.

  6. #6
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,702
    Quote Originally Posted by Cadrion View Post
    No, the oil that I see round the leaks is just enough to make it wet and cause it to get dirty...seems to have been like that for a while, no puddles to be seen. When I return I'm planning on doing a few things I've read on this site and some of the proceedures listed in the manual. Really nice to be able to sit and read without worrying about someone looking over my shoulder. The level was maintaining close to setpoint in B but A was off the indicator and the econo was open more than 75% If B is low, it may not be horribly low, but A has my attention. Considering the blanketed coils for B I wondered f there was a high pressure load limitation that the controls put on it- and thinking back, it wouldn't load both stages. after I gave it a quick brush down it loaded both stages. This may explain the B oil loss- running a lon time with partial load.

    Today was just the first visit, so I'll be going back with more ammo. I'm probably going to pull the charge on A and weigh it to verify it after a leak check.

    Thanks for the input guys.

    Kinda weird thou that your exv wasn't running at 100 % for a presumed low circuit. Not saying it not low but just don't jump to conclusions.
    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.

  7. #7
    Join Date
    Feb 2003
    Location
    Wichita Ks
    Posts
    1,457
    on those chillers oil will normally be in 3 places, on the ground, in the oil seperator like it should or in the evap. the evap is a flooded barrell so the charge needs to be full and exv needs to be operating properly. I would first check all sensors, temperature and pressure. if your evap is running low you will have a hard time bringing any oil back. of all the sensors I have seen get out of calibration would be the discharge temp sensor. it plays a big role in the exv operation as it looks at discharge superheat.

  8. #8
    Join Date
    Oct 2011
    Location
    South Georgia
    Posts
    64
    The oil return from the cooler is accomplished by having the cooler refrigerant level high enough to pull oil into the suction scavenger plate. Refrigerant charge with clean condensors should be 20-30 degrees condensor subcooling. Freonrick's post about the discharge superheat measurement is correct. The exv looks at evaporator temperature to be above brine freeze point, then it starts trying to get the discharge superheat into the setpoint range. I have also had these machines give me fits about oil return because the cooler tubes were dirty. Anything that prevents violent boiling of refrigerant in the cooler at the proper cooler refrig. level inhibits oil return.

  9. #9
    Join Date
    Jun 2011
    Location
    Detroit, MI
    Posts
    66
    Hey guys, just wanted to give an update- the same night I posted on here I took some time and read through the lit i have on it and got a better understanding of the chiller and software. Returned to site and performed checks on sensors, exv's, fans, etc. all seemed to be in decent shape so I proceeded to to pull the charge on the A circuit. As that was happening I ran a quick leak check and found two major leaks and repairs them. Cleaned the condenser on B. A should have had 339# and i pulled a total of 201#- took into account about 4 gal of oil and came up with about 175# in my tanks. Recharged the recovered (partial first into the serperator and waited for it to boil off to leave some oil in there) and finished off the charge. It's been running beautiful ever since. B with a total of 180# was 50# light.

    Funny how sometimes rough situations like that test you and you get stressed, then you over come the obsticle after getting your head back on straight and you end up feeling great about the whole thing. Thanks for all the replies- especially the unit specific info- I'll keep my eye on some of those items.

    One thing I did wonder- there is a schraeder both on top and bottom of the seperator where it looks like the oil side is. Can that be used with a couple of hoses and a sight glass to find out the actual oil level similar to the procedure on a Trane RTHC to check the sump level? I know the bottom valve is to dump the oil...and while the top is for charging I wondered about the uses of these for checking the level to troubleshoot the oil float if it ever comes up.

    Thanks again.

  10. #10
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,702
    Quote Originally Posted by Cadrion View Post
    Hey guys, just wanted to give an update- the same night I posted on here I took some time and read through the lit i have on it and got a better understanding of the chiller and software. Returned to site and performed checks on sensors, exv's, fans, etc. all seemed to be in decent shape so I proceeded to to pull the charge on the A circuit. As that was happening I ran a quick leak check and found two major leaks and repairs them. Cleaned the condenser on B. A should have had 339# and i pulled a total of 201#- took into account about 4 gal of oil and came up with about 175# in my tanks. Recharged the recovered (partial first into the serperator and waited for it to boil off to leave some oil in there) and finished off the charge. It's been running beautiful ever since. B with a total of 180# was 50# light.

    Funny how sometimes rough situations like that test you and you get stressed, then you over come the obsticle after getting your head back on straight and you end up feeling great about the whole thing. Thanks for all the replies- especially the unit specific info- I'll keep my eye on some of those items.

    One thing I did wonder- there is a schraeder both on top and bottom of the seperator where it looks like the oil side is. Can that be used with a couple of hoses and a sight glass to find out the actual oil level similar to the procedure on a Trane RTHC to check the sump level? I know the bottom valve is to dump the oil...and while the top is for charging I wondered about the uses of these for checking the level to troubleshoot the oil float if it ever comes up.

    Thanks again.
    You can only check the oil level while it's off using those 2 fittings.
    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
    Jun 2011
    Location
    Detroit, MI
    Posts
    66
    Ah, thanks for the heads up.

  12. #12
    Join Date
    Jun 2012
    Posts
    527
    Good thing you did not start pumping oil in. We had a guy put in an embarrassing amount of oil in a GX. GX and HX both like to hide their oil every once in awhile. We just had an HX that had one of it's compressors offline for about a month. Bye bye oil. If you jump the oil level switch and let it eat for awhile it will come running home usually.

  13. #13
    Join Date
    Jun 2011
    Location
    Detroit, MI
    Posts
    66
    The only time I've ever gotten into jumping stafties out has generally been if I could prove the were malfunctioning to myself. I imagine the price of an 06N heavily outweighs the cost of a couple gallons of oil being pumped in then removed. I'd hate to have to explain how the rotors gots so scuffed up In this instance the oil woun't have come back because of all the refrigerant loss. She's been purring along ever since.

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