At what pressure should relay pumpers set their intake pressure relief valves during a relay operation?

• A. 10 psi above the discharge pressure of the previous pumper
• B. 5 psi above the discharge pressure of the previous pumper
• C. 15 psi above the discharge pressure of the previous pumper
• D. 20 psi above the discharge pressure of the previous pumper

Answer: (A)

In a relay operation, the intake pressure relief valves of relay pumpers should be set to 10 psi above the discharge pressure of the previous pumper. This is important because it ensures that the relay pump maintains adequate intake pressure while preventing the pump from drawing in air, which can lead to cavitation and reduces the efficiency of the pumping operation.

Setting the relief valve too low might result in insufficient intake pressure, risking the pump's ability to maintain flow and pressure throughout the relay operation. Conversely, setting it too high could cause unnecessary stress on the system and potentially lead to failure. Therefore, 10 psi above the previous pumper's discharge pressure strikes a balance that allows for smooth operation and effective management of the water flow in a relay scenario.