Any incompatibility between base oil and refrigerant may destroy a refrigeration compressor

Refrigeration compressor lubricating oil is usually mixed with a special additive and base oil to provide the necessary lubrication performance, while also being compatible with the refrigerant. Any incompatibility between base oil and refrigerant can lead to catastrophic results for the equipment.

Most compressor lubricants are synthetic. This allows them to have a longer service life and face the severe tests of the system better than mineral base oils. Most home air conditioners now use a mixed refrigerant called R-410A. The application of polyol ester (POE) base oil is beneficial to the lubrication system, and this oil can also be separated from the refrigerant.

Although compatibility between refrigerants and lubricants may be the most pressing lubrication problem, there are many other aspects. For example, water pollution is harmful to many synthetic base oils that are unstable in hydrolysis. Moisture reacts with base oil to form acid, which changes viscosity and impairs lubricity. This may cause premature compressor failure and improper system cooling.

Lubricant problems are common in any system. One way to avoid problems with the gas being compressed is to simply remove the lubricant from the reaction formula. This situation often occurs when "dry" compressors become more widely used. "Dry" refers to the lack of oil in the compression chamber. If the lubricant is not in the compression chamber, it will not easily cause problems with the refrigerant. However, in a humid or water compressor, the oil is present in the compression chamber and is intimately mixed with the refrigerant. In these systems, the compatibility of the lubricant and the refrigerant is the most important.

Many large compressors use a forced lubrication system, which has an oil reservoir, pipes and pumps. The pump pushes the oil through the pipeline into the compressor to achieve lubrication and cooling, and then returns to the oil reservoir. The operation of these systems allows you to filter, cool, and separate gas and water from oil.

Smaller compressors are usually static lubrication systems in which the compressor preserves oil and the system is completely sealed. As long as it is cleaned and sealed before use, this type of system is less likely to have lubricant failure. In most cases, these systems will operate for many years without the need for oil changes. Lubricating oil is present in the compressor for lubrication, but some oil will flow out through the refrigerant line. In some cases, it is necessary to use an oil sump or knock out the method to prevent the oil from blocking the pipeline and reduce the cooling capacity of the system.