What is a common attribute of most semi-hermetic pumps?

A common attribute of most semi-hermetic pumps is that the bearings are lubricated by the liquid refrigerant. In semi-hermetic compressors, the motor and the pump components are housed together in a single casing, which means that the bearings are effectively immersed in the refrigerant. This immersion not only cools the bearings but also provides necessary lubrication, contributing to the efficient operation and longevity of the pump.

This design ensures that the pump can operate in various temperatures and pressures, with the lubricating properties of the refrigerant playing a crucial role in maintaining the bearings and preventing wear. When operated correctly, this method reduces maintenance needs and enhances the pump's reliability because the need for external lubricant sources is minimized.

Understanding this aspect of semi-hermetic pumps is vital for troubleshooting and maintenance, as proper lubrication is key to preventing failures associated with bearing wear.