Which device protects main fuel pumps against excessive pressure?

• A. Check valve
• B. Pressure relief valve
• C. Regulator
• D. Bypass valve

Answer: (B)

The device that protects main fuel pumps from excessive pressure is a pressure relief valve. It is set to open at a predefined discharge pressure, and if the pump pushes fuel too hard, the valve pops open and allows fuel to return to the tank or to a lower-pressure point. This keeps the pump, lines, and fuel controls from being stressed or damaged by overpressure, ensuring safe and reliable operation.

Other devices serve different roles: a check valve prevents reverse flow, a regulator maintains a desired downstream pressure under normal conditions, and a bypass valve redirects flow to prevent blockage or overload but isn’t primarily a safety release for pump overpressure.