Lambert, S., Jamo, W., and Kurtz, M., "Automotive A/C Servicing – Refrigerant Flushing of a Failed A/C System," SAE Technical Paper 2017-01-0167, 2017, doi:10.4271/2017-01-0167.
The failure of an A/C system often results in the introduction of contaminants to the A/C system. The sources of the contaminants include debris from damaged components and debris from the surrounding environment. Returning the A/C system to service requires the removal of these contaminants from any reused components. The recommended approach to cleaning contaminated components and systems is to flush with a solvent flushing machine. Previous internal studies have concluded that solvent flushing will remove all contaminants, restoring component and system performance. Many commercial refrigerant recovery and recharge machines include a refrigerant “flush” feature which can flush oil from the system and components with the systems refrigerant. The effectiveness of using the “flush” feature of a refrigerant recovery and recharge machine with an added in-line filter to remove contaminants is investigated. One gram of Arizona Test Dust is introduced to the suction line of an automotive A/C system, and the system is run to compressor failure. This introduces debris from the damaged compressor into the condenser and the rest of the system. The condenser is removed, and the refrigerant recovery and recharge machine with the added in-line filter is used in “flush” mode in an effort to remove the debris from the condenser. The condenser is sectioned and inspected to evaluate the effectiveness of the debris removal. Two machines, made by different manufacturers, were selected to represent machines typically used in A/C service operations. Several compressors were failed in order to create contaminated condenser samples. The condensers were then flushed for varying lengths of time, filled with epoxy, sectioned and photographed under microscope for cleanliness evaluation.