What steps should the operator take if the pump gauge indicates air in the discharge lines?

What steps should the operator take if the pump gauge indicates air in the discharge lines?

• A. Stop, verify priming, check for leaks, bleed air, and restart with prime if necessary
• B. Increase throttle
• C. Open discharge valve more
• D. Ignore it if PDP is met

Answer: (A)

Air in the discharge lines means the pump hasn’t established a continuous column of water and can’t deliver water at the designed pressure. The remedy is to remove the trapped air and re-prime the pump before returning to service. Stop the pump and verify the priming system and water source are functioning. Check all suction and discharge connections for leaks or openings that could admit air, and make sure the suction line is fully filled with water. Bleed the air from the pump and discharge lines by opening the intended bleed points until a steady stream of water (without air bubbles) comes out. Once the lines are full of water and the air is purged, re-prime the pump if needed and restart at the proper operating speed, monitoring gauges to confirm the discharge pressure and flow stabilize. Why the other options aren’t appropriate: simply increasing throttle won’t remove trapped air and could cause cavitation or damage. Opening the discharge valve more may vent air but won’t eliminate the root cause and can hide the problem without priming. Ignoring the condition if the PDP is met is unsafe because air pockets can prevent delivering water even when pressure appears adequate.

Air in the discharge lines means the pump hasn’t established a continuous column of water and can’t deliver water at the designed pressure. The remedy is to remove the trapped air and re-prime the pump before returning to service.

Stop the pump and verify the priming system and water source are functioning. Check all suction and discharge connections for leaks or openings that could admit air, and make sure the suction line is fully filled with water. Bleed the air from the pump and discharge lines by opening the intended bleed points until a steady stream of water (without air bubbles) comes out. Once the lines are full of water and the air is purged, re-prime the pump if needed and restart at the proper operating speed, monitoring gauges to confirm the discharge pressure and flow stabilize.

Why the other options aren’t appropriate: simply increasing throttle won’t remove trapped air and could cause cavitation or damage. Opening the discharge valve more may vent air but won’t eliminate the root cause and can hide the problem without priming. Ignoring the condition if the PDP is met is unsafe because air pockets can prevent delivering water even when pressure appears adequate.