How should you correct a failed check valve in this setup?

• A. Close the gate valve to the spare pump, make the spare prime the primary, then reopen the gate valve
• B. Increase the pump speed
• C. Replace the valve at once
• D. Operate without the spare

Answer: (A)

When a check valve isn’t functioning, the priority is to prevent backflow and keep the system running safely on the available equipment. Closing the gate valve to the spare pump isolates the path from the failed check valve, so backflow can’t undermine the spare or cause loss of prime in the line. Making the spare pump the primary ensures the system is now powered by the healthy unit, with its prime established, and then reopening the gate valve reestablishes flow through the spare. This keeps the system pressurized and ready, while avoiding the risks of backflow or losing prime.

Increasing pump speed won’t fix the valve and can worsen issues like backflow or cavitation. Replacing the valve is a proper long-term repair, but the immediate corrective action is to isolate the failed valve and switch duties to the spare so operation can continue. Operating without the spare eliminates redundancy and increases the chance of a complete shutdown.