Which marking indicates the direction of unrestricted flow on a check valve?

Which marking indicates the direction of unrestricted flow on a check valve?

• A. Tag on the switch handle
• B. Arrow on the casting
• C. Colored symbol on the handwheel
• D. Lettered sign

Answer: (B)

Flow direction is shown by an arrow on the valve body casting. This arrow points the path that the fluid is allowed to take, which is essential for a check valve that opens in one direction and closes to prevent backflow. Installing the valve so the flow follows the arrow ensures it functions correctly and doesn’t block or reverse flow. Other indicators like a tag on a switch handle or a colored symbol on a handwheel aren’t standardized ways to communicate flow direction, and a lettered sign is typically for identification or service notes rather than indicating how the valve should be oriented.

Flow direction is shown by an arrow on the valve body casting. This arrow points the path that the fluid is allowed to take, which is essential for a check valve that opens in one direction and closes to prevent backflow. Installing the valve so the flow follows the arrow ensures it functions correctly and doesn’t block or reverse flow.

Other indicators like a tag on a switch handle or a colored symbol on a handwheel aren’t standardized ways to communicate flow direction, and a lettered sign is typically for identification or service notes rather than indicating how the valve should be oriented.