What should be done before opening an oil fill crankcase plug on a semi-hermetic compressor?

Before opening an oil fill crankcase plug on a semi-hermetic compressor, it is essential to ensure that pressure is removed from the compressor crankcase. This is critical because compressors operate under pressure, and opening the crankcase plug without relieving that pressure can lead to oil spray or even an explosion risk due to the sudden release of pressure.

By safely relieving the pressure, you protect yourself and the equipment, ensuring that the operation can be performed safely and effectively. This step is a fundamental safety measure in maintenance practices when dealing with any type of pressurized systems, especially those containing volatile substances like oil in a compressor.

While checking the crankcase temperature or oil level and energizing the system are relevant maintenance activities, they are not prerequisites for safely opening the oil fill crankcase plug. Focusing on ensuring that the pressure is removed is the primary concern to avoid dangerous situations during the maintenance process.