Red Seal Heavy Duty Equipment Technician Practice Exam

What role does a pressure relief valve serve in hydraulic systems?

1. To increase system pressure

2. To divert flow under excessive pressure

3. To filter hydraulic fluid

4. To monitor fluid quality

The correct answer is: To divert flow under excessive pressure

A pressure relief valve is a crucial component in hydraulic systems, primarily designed to ensure safety and protect the system from excessive pressure. When the pressure in the hydraulic system exceeds a predetermined limit, the pressure relief valve opens, allowing fluid to escape, which helps reduce the pressure within the system to a safe level. This function prevents potential damages or failures that could occur due to overpressure, such as ruptured hoses, damaged seals, or catastrophic failure of components. In contrast, the other options don't effectively describe the function of a pressure relief valve. Increasing system pressure is typically achieved by pumps, not relief valves. Filtering hydraulic fluid is the role of a filter, while monitoring fluid quality involves sensors and gauges, which are unrelated to the pressure relief valve’s primary function. Thus, the role of a pressure relief valve is specifically centered around diverting flow to manage excessive pressure effectively.