Figure 7-41. - Procedures for observing operating pressures, charging, purging, and evacuating a unit.
A refrigerant system can become badly contaminated for a number of reasons.
The compressor may have failed due to damage or wear.
The compressor may have been run for some time with a severe leak or an opening in the system.
The system may have been damaged by a collision and left open for some time.
The system may not have been cleaned properly after a previous failure.
The system may have been operated for a time with water or moisture in it.
A badly contaminated system contains water, carbon, and other decomposition products. When such a condition exists, the system must be flushed with aspecial flushing agent, using equipment designed especially for this purpose. Follow the suggestions and procedures outlined for proper cleaning.
A refrigerant to be suitable as a flushing agent must remain in the liquid state during the flushing operation to wash the inside surfaces of the system components. Refrigerant vapor will not removeContinue Reading