A dirty term in our industry is “call back,” meaning a system that a technician just repaired is not working, and it becomes necessary to go back and repair the problem again. This is especially true after changing out a compressor. Replacing a compressor is typically a major investment for a customer and a time-consuming job for a technician, so having to return and repair the same issue, or an additional issue, should be avoided. It is not possible to prevent all call backs, but here are some common mistakes to avoid.
It is a good practice to check for an acidic refrigerant before and after replacing a compressor. If the refrigerant is found to be acidic, it will be necessary to clean up the system during the repair. Do not allow the new compressor to operate with a contaminated refrigerant. In addition, always replace the liquid line filter/drier during the repair. This helps to safeguard the system from circulating unwanted containments that may have been left in the system.
On systems using a compressor contactor, it is a good practice to change out the contactor during the repair, especially on a three-phase compressor. A defective contactor could cause a three-phase compressor to single-phase. It is also wise to replace the starting components on single-phase compressors.
Some compressors may utilize a steel discharge stub connection, so be sure to check for this feature. A copper-to-steel connection generally requires using a higher percentage silver alloy for its connection. Using the wrong alloy could lead to a leaking joint.
After changing out the compressor, be sure to check its discharge line temperature and make sure it is not too excessive. A very common cause of compressor failure is overheating. Also check the compressor’s returning refrigerant superheat condition. An excessive superheat value or too low a superheat value could lead to future issues with the new compressor.
Always check that no service ports are leaking after removing the service gauges because many times, the valve stems or the valve itself will leak. This may go unnoticed and cause refrigerant to leak out of the system. It is also good practice to always make sure the service port caps are in place. This will serve two purposes: 1) if the valve is leaking, the cap might be enough protection to correct the leak; and 2) if left uncapped, the port could rust over and cause the next technician on the job to be unable to install service gauges.
Lastly, if the system was converted to a different refrigerant, be sure to mark the system with the new type. This will let the next technician on the job know that the refrigerant has been changed over and what the new type is. If the new refrigerant is not marked on the equipment, the next technician may not know that it has been converted, and this could lead to problems.
Avoiding all return visits after changing out a compressor may not always be practical, but avoiding some of these common pitfalls can help.
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