When should a technician check a hermetic compressor for a permanently open internal overload protector?

A hermetic compressor may have a built-in overload protector designed to safeguard the compressor from overheating by interrupting power if a certain temperature threshold is exceeded. Checking the overload protector when the compressor is cool ensures that the technician can accurately assess its condition without any influence from heat generated during operation.

If the compressor is energized or running, there is the risk of falsely interpreting the status of the overload protector due to heat and current flowing through the system, which might mask issues such as a short circuit or a stuck overload. Additionally, if the compressor is hot, that could indicate an existing problem that needs to be diagnosed and wouldn't provide a reliable evaluation of the overload protector itself. Therefore, checking it while the compressor is cool allows for a more reliable assessment of its functioning.