York Millenium Model# YSBBBSO-CFC
135 ton (or so I am told)
Compressor # 163S
Rotary Screw Compressor
Problem: high oil filter pressure differential.
I had just replaced both oil filters 3 months ago. (this has the twin oil filter system that runs only one filter at a time. You can move the lever to switch between the oil filters). And we also had the oil tested at the same time by Trane Labs. All okay.
This chiller went off on "clogged oil filter". I noticed oil was pumped out of oil separator, into the evap, and also locked out on low oil level.
I pumped some oil in to the separator for start up (1 gallon York C type oil).
I started the chiller and it went off after about 30 second on "clogged oil filter. Filter differential was 28 psi.
I tried the other filter, and it did the same thing.
I replaced both the oil filters, and the filter differential started at 9 psi, and rose to 17.5 after 10 min. run time. I noticed a "excessive refrigerant charge" warning. Maint told me they added 100 lbs r-22 last month to get TD up.
I removed 100 lbs r-22 and let run over night with a 50 degree discharge superheat.
I returned in the AM and all oil had returned, but noticed the filter differential pressure rose to 20.5 overnight, and a "dirty oil filter" warning was present.
I balanced discharge superheat to 45 degrees at full load with 55 degree CW IN tempand 55degree CW OUT. Refrigerant Pressures are 209 discharge and 72 suction.
Oil Temp is 119 leaving the oil cooler (verified with a thermanometer), oil solenoid is energized.
Oil Pressure is 228.
There is one oil transducer located at the bottom of the oil separator and one in a metal block located in the outlet of the oil cooler eat exchanger. This metal also has the oil temp sensor in it.
It seems to have a restriction some where in the oil filter/cooling circuit.
Oil pressure transducers zero out when system is shut down.
Is there a strainer in this circuit?
Could the oil cooler be restricted?
Is there anything else I should look for?
Any help would be very helpful.
I have verified the filters are correct, and the exact same chiller next to is runs a 9.5 oil filter differential and has the same filters.
Thanks in advance.