If the discharge check valve were to fail closed, what is a likely consequence?

If the discharge check valve were to fail closed, what is a likely consequence?

• A. Backflow into the discharge line and potential loss of discharge pressure after pump stops.
• B. Increased suction pressure.
• C. No impact on system pressure.
• D. Reduced need for jockey pump.

Answer: (A)

The discharge check valve’s job is to prevent backflow from the discharge line into the pump and to help maintain discharge pressure when the pump isn’t running. If that valve sticks closed, the discharge path is blocked. Water in the system can’t push through to the discharge line, so the pump can’t transmit pressure out into the system when it runs. When the pump stops, the trapped water in the discharge line tends to flow back toward the pump area, causing backflow into the discharge line and a rapid loss of discharge pressure as the system pressure recedes. This is the most likely consequence you’d see. The other options don’t fit because the suction side wouldn’t experience higher pressure simply from a blocked discharge path, the system pressure would be affected (not “no impact”), and the jockey pump’s role isn’t directly changed by a stuck discharge valve in this way.

The discharge check valve’s job is to prevent backflow from the discharge line into the pump and to help maintain discharge pressure when the pump isn’t running. If that valve sticks closed, the discharge path is blocked. Water in the system can’t push through to the discharge line, so the pump can’t transmit pressure out into the system when it runs. When the pump stops, the trapped water in the discharge line tends to flow back toward the pump area, causing backflow into the discharge line and a rapid loss of discharge pressure as the system pressure recedes. This is the most likely consequence you’d see.

The other options don’t fit because the suction side wouldn’t experience higher pressure simply from a blocked discharge path, the system pressure would be affected (not “no impact”), and the jockey pump’s role isn’t directly changed by a stuck discharge valve in this way.