What does a check valve do?

What does a check valve do?

• A. Allows flow in both directions
• B. Controls flow by adjusting pressure
• C. Regulates temperature
• D. Allows flow in one direction and prevents backflow

Answer: (D)

A check valve is a one-way valve. It opens to let flow move forward and automatically closes when flow tries to reverse, sealing the passage to prevent backflow. This keeps water from flowing back toward the supply and helps protect downstream equipment and the rest of the system. The other ideas describe devices that either allow flow in both directions, adjust pressure to control flow, or regulate temperature—functions that aren’t what a check valve does.

A check valve is a one-way valve. It opens to let flow move forward and automatically closes when flow tries to reverse, sealing the passage to prevent backflow. This keeps water from flowing back toward the supply and helps protect downstream equipment and the rest of the system. The other ideas describe devices that either allow flow in both directions, adjust pressure to control flow, or regulate temperature—functions that aren’t what a check valve does.