Trane Chiller model e oil loss help

[icebathcurt]

:confused:Working on a Trane chiller 200tons. 2 model E comp, 2 seperate circuits 100 tons each. Compressor on chilled water leaving side of barrel running fine. Comp on chilled water entering side and condenser water side loses oil after running for a few minutes.trips on oil. Adjusted gpm on both barrels from high to low and inbetween design delta p. Condser water 70 entering 75 to 80 leaving depending on bypass. Change txv, driers,lls,oil pressure control. Compressor one keeps washing oil.Head pressure 150 to 200. ejector tower no fan 300 or so nozzels. Both compressors run same suction,disch, 55 to 80, 150 to 200, 70 to 75 ambient. beetween 50 to 75 entering chilled water and from 50 to 60 out. 3 unloaders. Could compressor itself pump out oil . Primary sec loop. compressor 2 bring down temp to any setting. 40, 50,.
Tried adjusting water flow evap and cond, txv, oil wont stay in comp. Eddy current and oil test good, refrigerant analysis moisture. Comp one has been changed twice in 8 years by a different comp. During all of this comp 2 just stays running. I am starting to think it is a internal problem in compressor . Could there be problem in evap circuit one. heater ok, new r22 after 500 micron evac. evap barrel problem? or time for new comp?
trane chiller 20 years old. cgwcd 201 comp crhe

[jayguy]

there are lots of places to measure "differential oil pressure"...

"low side" could be on the suction, could be on the crankcase...

"high side" could be on the oil pump, could be on the side cover near the unloaders...

what are your pressures at these points?

where are your taps? what is your differential oil pressure trip point?

losing the oil to the system is normal...especially at start up...you just want it to come back. your head pressure seems a little low. getting that up should help at least in the short term until you can find the real issue (assuming that it is not internal to the compressor). does the system ever get to run much? or does it just trip only?

i did not see any subcooling numbers.

you may have issues internally, but that is somewhat labor intensive just to look, so lets give the outside a good look-see. my initial guess is that it is not a "system" issue. your other compressor works just fine, so i would not adjust water flows as that would affect the other circuit. if the other circuit is fine...i would leave those common items alone.

good luck.

[jogas]

Trane recommends relocating the oil pressure connection from the oil pump to the hydraulic unloader cover. They have/had a kit for it. I put a couple on some E's long ago. This senses the oil supply to the unloaders. BTW, there's a screen under the plug on that hand hole cover.
Run the head up and see if the oil comes back. I've had systems that required a higher minimum head to insure oil return.
Also check the other thread on this issue about diagnosing oil pressure verses unloader staging.
jogas