Which safety device is crucial for preventing excessive pressure in a refrigeration system?

The pressure relief valve is critical for preventing excessive pressure in a refrigeration system because it is specifically designed to open and release pressure when it exceeds a predetermined limit. This is essential in maintaining the system's integrity and safety. When the pressure within the refrigeration system rises to unsafe levels due to factors such as a blockage or excessive heat, the pressure relief valve activates and channels the excess pressure away, preventing potential failures or dangerous conditions. It acts as a safeguard to ensure that the system operates within safe pressure ranges, thereby protecting both the equipment and personnel.

In contrast, while the pressure sensor monitors pressure levels, it does not take action to relieve pressure; it simply provides feedback. The temperature control valve regulates coolant based on temperature but does not specifically address pressure issues. Similarly, the expansion valve controls the flow of refrigerant in the system but is not designed to handle excessive pressure situations directly. Therefore, the pressure relief valve is the essential device for managing pressure and ensuring safety in refrigeration systems.