What is the function of a pressure relief valve?

The function of a pressure relief valve is crucial for maintaining safety and integrity within refrigeration systems. Its primary role is to prevent excessive pressure build-up by allowing refrigerant to escape when the pressure exceeds a specified limit. This safeguard is essential because excessive pressure can lead to component failure or, in extreme cases, catastrophic explosions. By automatically venting excess pressure, the valve protects the system from damage and ensures safe operation, which is vital in any refrigeration application.

The other options do not accurately reflect the role of a pressure relief valve. Increasing system pressure for better efficiency or regulating the temperature of the refrigerant would not correctly describe the purpose of the valve and could lead to system malfunctions if applied as intended functions. Likewise, while facilitating the passage of refrigerant is part of the general operation of the system, it is not the specific purpose of a pressure relief valve. Thus, the correct response highlights the valve's safety function, crucial for safe refrigeration system operation.