Cleanliness is especially important when servicing compressors because of the very closed tolerances used in these units. Consequently, repairs to the compressor itself should not be attempted unless all proper tools are at hand and a spotless work area is provided.
Any time the system has been opened and sealed again, it must be properly evacuated. Keep in mind that the complete and positive sealing of the entire system is vitally important and that this sealed condition is absolutely necessary to retain the chemicals and keep them in a pure and proper condition.