I have a commercial walk-in refrigerator purchased used. It was built in 2003. It looks like it's designed for R22 according to the paperwork.

Do I have the option of using R134a instead? What about compatability with the oil that is currently in the compressor?

note.. The reason for wanting to go this way is that I'm not a professional. As a layman, it's a lot easier to get R134a. The few technical papers I've seen indicate that performance is off only 2-3% by moving to R134a & that is a negligible penalty for me.

Mike