I am working on a Grunert engine driven boat refrigeration system. This system uses a Sanden wobble plate compressor identical to those used on car air conditioners, and originally operated on R-12. For some unknown reason, the screen on the oil orifice in the suction accumulator plugged and almost all of the mineral oil in the system became trapped in the accumulator tank. I have flushed the entire system and installed a new accumulator and a suction filter dryer. The compressor seems to be in good condition.
Since all of the old oil is out of the system, I thought this would be a good opportunity to replace the mineral oil with PAG or POE oil and run the system on R-134a refrigerant. I corresponded (Email) with the manufacturer (now Dometic) but cannot get an answer from them on the refrigerant change. Sanden Compressors endorses the change and provides a retrofit guide. In my experience, the R-12 TEV and the low and high pressure switches work with R-134a.
Does anyone see a problem with this refrigerant change?