Any time a refrigeration system is opened to the atmosphere, it must be completely evacuated before refrigerant can be added back into it. Proper evacuation of a system is an important part of the overall repair process. It ensures that no atmospheric air remains in the system.
Owners of commercial refrigeration systems containing 50
pounds of CFC or HCFC refrigerants are required by the Environmental Protection
Agency (EPA) to repair refrigerant leaks when the leak rate equals or exceeds
35 percent of the total system charge over a one-year period.
The correct placement and installation of a
thermostatic expansion valve’s (TXV’s) sensing bulb is important to its overall
performance and reliability. An incorrectly installed or placed sensing bulb
can lead to two major system problems.
A suction-line accumulator is a safety device used on a refrigeration system to prevent liquid refrigerant from returning to the compressor. Liquid refrigerant returning to a compressor can lead to several problems. One of these problems is bearing washout.
Refrigeration systems that contain polyolester (POE) oil present technicians with concerns that aren’t normally found with systems that use mineral-based or alkylbenzene oils. Refrigeration technicians need to be aware of these issues while servicing and installing POE systems, to prevent system problems from developing.
When the motor of a hermetic compressor burns out, it is possible for contaminants to form in the compressor, depending on the severity of the motor burn. It is also possible for these contaminants to be pumped out into the system.
The only fluids circulating within a refrigeration system should be refrigerant and oil. Any other fluids contained within the system may reduce its capacity and possibly cause harm to the system. One common contaminant that can enter a system is atmospheric air.
To prevent overheating of a hermetic compressor’s internal motor, some type of cooling method must be employed. Compressor manufacturers will use one of three methods to provide the necessary cooling for their motors.
Understanding manufacturers' nomenclatures to identify their compressors can be a very useful tool for a service technician. There is much information about a compressor that can be obtained from decoding its model number.
While troubleshooting small-capacity refrigeration systems, a technician should not be too quick to attach refrigerant gauges to a system. Small systems normally hold relatively small amounts of refrigerant. The process of attaching and removing a set of refrigeration gauges will release a small amount of refrigerant from the system.