There are three distinct design differences between and R-22 and R-410A compressor:
Different Oil: Because mineral oil, normally used in R-22 compressors, is not miscible with HFC refrigerants such as R-410A, Copeland uses a synthetic Polyol Ester Oil (POE) in R-410A approved compressors.
Reduced Compressor Displacement: A pound of R-410A has approximately the same heat carrying capacity relationship to R-22 as R-22 has to R-12, therefore, the compressor displacement has to be reduced approximately 40% for a given motor horsepower. Using a compressor designed for R-22 to pump R-410A would overload the motor and cause protector trips.
Higher Shell Burst Pressure Requirement: At any given saturated temperature, R-410A has approximately 60% higher pressure than R-22, which requires compressor shells to meet this higher pressure requirement.