Would love to here from all the techs out there that do oil changes on Refrigeration Racks. Is there a set way on how to do it? Does any of the old timers have a recommeded A to Z method? Lets just pick an old Hill Phoenix Low Temp. Rack with a AC&R oil seperaotor, reservior, and say 5 compressors with oil regulators. A oil changable core filter. R22 Mineral oil. Maybe we can have some fun with this and see if we can have the educational committee pick the best method. Lets pick October 1, 2012 the deadline. I'll go first on how I have always done mine!!!
First thing I do is pump the rack down in an attempt to pull as much of the old oil out of all the evaporator coils and all the traps. When all the compressors have shut off I'll force one on and run the suction down to about 3psig being sure not to go into a vacuum! At this point I will front seat the suction and discharge valves on all the compressors and shut off the oil feed to each oil regulator and the liquid on the demand cooling line Start at compressor # 1 and pull the pick-up screen and oil safety sensor. Do this to each compreesor. Clean all and replace. Install new oil filter. Pull the oil float from the seperator and install new one. Drain all oil from reservoir. Pump in the new oil --approx. 1-gal. per. compressor and or 1st ball up on reservoir. Since the rack is already pumped down I alway install new filter/dryers. Pull good vacuum. Open all the lines that were closed off exept for the suction lines. Open up suction line on #1 compressor Slowly start each compressor ensurring no liquid is comming back!!
How do you do yours?