Draft from a static source, open booster line to prevent losing prime. Which action best matches this guidance?

• A. Increase discharge pressure
• B. Prevent Losing Prime
• C. Vent the supply
• D. Close the booster line

Answer: (B)

Drafting from a static source requires keeping the pump primed, so the suction line stays filled with water and air isn’t drawn in. Opening the booster line helps maintain that prime by providing a continuous water path from the source into the pump’s priming circuit, pushing out any trapped air and preventing the suction from going dry as source level or line conditions change. The guidance you described focuses on preventing prime loss, which is exactly what keeping the booster line open accomplishes. Raising discharge pressure doesn’t directly prevent prime loss and can cause cavitation; venting the supply can introduce air and disrupt prime; closing the booster line cuts off the booster feed and makes prime loss more likely. So the action that matches the guidance is to prevent losing prime.