In larger capacity refrigeration compressors, which valves should be operated prior to starting?

Before starting larger capacity refrigeration compressors, it is essential to manage the conditions in the system to prevent damage and ensure proper functioning. The correct approach is to open the discharge valve and close the suction valve prior to starting.

This procedure allows for the creation of an initial pressure in the system, which is crucial because it helps protect the compressor from potential issues associated with low pressure. If the suction valve were to remain open while the discharge valve is closed, the compressor might attempt to draw in vapor at extremely low pressure, which could lead to liquid refrigerant entering the compressor and causing damage.

By opening the discharge valve, the compressor can properly vent and allows for any trapped gases to escape, creating a safe and stable environment for operation. Closing the suction valve ensures that the compressor will not draw in any refrigerant until it is ready to do so safely and effectively. Once the compressor has started, the suction valve can then be opened to allow for normal operation. This procedure helps maintain system integrity and optimizes performance.