What is the main purpose of a suction line check valve?

• A. To prevent backflow and maintain prime
• B. To increase water temperature
• C. To slow water velocity
• D. To heat water

Answer: (A)

A suction line check valve is a one-way valve placed in the suction line that prevents water from flowing back toward the source and keeps the pump’s suction filled with water. Its main job is to maintain prime so the pump doesn’t lose its suction when the system experiences shifts, such as starting to draft from a source, sudden discharge changes, or stopping and restarting the pump. If backflow were allowed, air could be drawn into the suction line, causing loss of prime, cavitation, and difficulty keeping the pump running smoothly.

This valve doesn’t affect water temperature, speed, or heating. Its purpose is specifically to stop reverse flow and preserve prime for reliable pumping.