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. This can be a valuable aid for a technician when trying to select a compressor for replacement if the original compressor is not readily available or no longer in production. It can also be helpful while troubleshooting a compressor.

Every compressor manufacturer has its own nomenclature for its series of compressors. The information contained in the model number will vary from manufacturer to manufacturer, so technicians will need to obtain the coding used for each of the different compressors they service. This is not a difficult task; the information is usually readily available from the manufacturer in service publications.

Below is some of the information that can be obtained from the nomenclature of a compressor's model number:

The physical characteristics of the compressor series, such as its footprint, body dimensions, and layout of its stub or service valve connections. On a replacement compressor, when the original compressor is not available, this can allow a technician to determine if the replacement will fit into the space available.

Some model numbers will also include the type of refrigerant originally designed for the compressor.

Many times the application range of the compressor can be determined - if the compressor is designed for a high, medium or low temperature application.

The Btu capacity is normally included in the nomenclature of the compressor model number. Sometimes instead of the Btucapacity, the model number will state the compressor's motor horsepower or its displacement.

Some models will state the type of oil originally included with the compressor.

Sometimes the compressor motor type is stated in the model number. It will state if the compressor incorporates a PSC, capacitor, start, or another motor design. This can help a technician identify which types of starting components are used.

Many model numbers also include the type of compressor motor protection. This helps a technician determine if there is an internal overload device, which could be open and be the cause of an infinite resistance reading when measuring the resistance values of a compressor.

More than likely the voltage rating of the compressor will be stated. Again, this can be useful when troubleshooting a compressor and trying to determine if the correct voltage is being applied.

Some model numbers will state if the compressor is new or a service replacement.

The figure above shows an example of compressor nomenclature.

The serial numbers of many compressors may also include some valuable information. Knowing the nomenclature of a compressor's serial number many times will allow a technician to identify the date the compressor was manufactured. This can be handy when determining the warranty status of a compressor. Again this information can normally be obtained from a compressor manufacturer's service literature.

Publication date: 11/06/2006