Which action is best as an initial check when a pump cannot prime due to a stuck or unlocked priming valve?

• A. Inspect valve for binding or obstructions, verify linkage, check gaskets; ensure priming device is functioning; retest priming after repair.
• B. Replace the pump with a spare.
• C. Ignore and attempt to start again.
• D. Disconnect the priming line and run dry.

Answer: (A)

When priming fails because the priming valve is stuck or not fully engaged, the first step is to examine the priming valve assembly and its control parts. Look for binding or obstructions in the valve that would keep it from sealing properly, and verify that the linkage and actuator are moving freely and fully to the correct position. Worn or damaged gaskets around the valve can allow air to leak and ruin the prime, so inspect and replace any questionable seals. Also confirm the priming device itself is functioning correctly, since a malfunctioning primer won’t establish suction even if the valve is okay. After cleaning, adjusting, or replacing components as needed, retest the priming to confirm that the system can establish and sustain prime. Avoid jumping to pump replacement or restarting without addressing the valve and priming mechanism, and don’t disconnect the priming line and run dry, as that can cause damage and won’t resolve the underlying issue.