Nate Core Practice Test 2025 - Free Practice Questions and Study Guide

The essential safety device for preventing excessive pressure buildup in refrigeration systems is the pressure relief valve. This device plays a critical role in maintaining the safety and functionality of the system by allowing excess pressure to escape when it exceeds a predetermined level. This is important because high pressure can lead to system failures, leaks, or even explosions if not managed properly.

The pressure relief valve is designed to automatically open and release refrigerant when the pressure reaches a certain threshold, thereby protecting the system from potential damage. By ensuring that pressure levels remain within safe operating limits, this device helps to maintain the integrity and efficiency of refrigeration systems.

The other options, such as the expansion valve, shut-off valve, and accumulator, have different functions that do not directly address the issue of excessive pressure buildup. While they are important components in a refrigeration system, they do not provide the same level of immediate protection against dangerous pressure levels as a pressure relief valve does.