What is the difference between a hermetic and a semi-hermetic compressor?

A hermetic compressor is designed to be fully sealed with the motor and the compressor unit combined into one single unit, which means that it cannot be opened for repairs once it is manufactured. This design helps prevent refrigerant leaks and contamination, making hermetic compressors ideal for applications where reliability and maintenance-free operation are crucial.

On the other hand, a semi-hermetic compressor has a similar sealing mechanism but is constructed in a way that allows the unit to be disassembled by removing the bolts that hold the casing together. This feature enables technicians to perform repairs or maintenance on the compressor without having to replace the entire unit, offering a practical solution in cases where issues arise.

This distinction between the two types of compressors highlights their differences in repairability and serviceability, making the correct answer one that emphasizes the hermetic unit's inability to be serviced once sealed compared to the semi-hermetic option.