Check valves on the discharge side of centrifugal pumps serve to

• A. Regulate discharge pressure
• B. Cool the pump
• C. Increase backflow into the pump
• D. Prevent water in discharge line from flowing back

Answer: (D)

Check valves are one-way devices that prevent flow from reversing in a piping system. When placed on the discharge side of a centrifugal pump, they close if the flow tries to reverse or if the pump stops, so water in the discharge line cannot push back toward the pump or into the suction side. This protects the pump from reverse flow, helps prevent water hammer, and helps maintain the pump’s prime. They are not used to regulate discharge pressure, to cool the pump, or to create backflow. The key purpose is to stop backflow in the discharge line.