Cross Connection Practice Exam

Which condition indicates that a check valve is fouled during testing?

1. The test cock seals properly

2. Water pressure remains stable

3. Water flows backward through the valve

4. Water pressure drops significantly

The correct answer is: Water flows backward through the valve

A fouled check valve allows water to flow in the wrong direction, which is why the correct condition indicating a problem during testing is when water flows backward through the valve. This backward flow suggests that the valve is not sealing properly, potentially due to debris, mineral buildup, or mechanical failure, which prevents it from performing its intended function of allowing flow in only one direction. In contrast, when the test cock seals properly, it indicates that there is no leak, and the check valve is likely functioning as expected. Stable water pressure further suggests that the system is functioning correctly without any obstructions or failures. A significant drop in water pressure could indicate other issues in the system, but it doesn't specifically reflect the performance of the check valve as directly as backward flow does. Therefore, water flowing backward is the most definitive indicator that a check valve is fouled.