Which statement about relief valve operation is correct?

• A. It increases water flow to the nozzle.
• B. It releases excess pressure to prevent overpressure in the discharge lines.
• C. It cleans hoses automatically.
• D. It seals the pump when not in use.

Answer: (B)

Relief valves are safety devices that keep system pressure from getting too high. When the pressure reaches the setpoint, the valve opens and diverts excess fluid away from the discharge path, typically back to the reservoir or to the pump suction, so the pressure is kept at a safe level. This protects hoses, fittings, and the pump itself from damage due to overpressure. They don’t add more flow to the nozzle; instead, they limit pressure by bypassing part of the flow. They also aren’t cleaning hoses or sealing the pump when not in use. The key idea is preventing overpressure by releasing the excess, which is exactly what this statement describes.