Backflow Prevention Practice Exam

A reduced pressure principle assembly's continuous discharge from a relief valve and a gauge reading of 4 psid to 5 psid may indicate _____?

1. A damaged check 1 guiding member

2. Debris fouling check valve number 1

3. A leaking shut-off valve number 2

4. Leakage through the diaphragm

The correct answer is: Debris fouling check valve number 1

The continuous discharge from the relief valve in a reduced pressure principle assembly, coupled with a gauge reading of 4 psid to 5 psid, suggests a situation where the pressure differential across the assembly is not being maintained effectively. This scenario typically indicates that there is an obstruction affecting the flow within the assembly. When debris fouls check valve number 1, it can prevent the valve from closing properly. This failure can lead to the backflow of water, causing the relief valve to discharge continuously to maintain the pressure difference required for the assembly to operate correctly. The pressure differential you're observing on the gauge indicates that the system is attempting to manage an imbalance, which the relief valve responds to by discharging. This condition is a direct result of the check valve being unable to perform its function due to debris, leading to the observed readings. In contrast, while a damaged check guiding member, a leaking shut-off valve number 2, or leakage through the diaphragm might lead to issues in other respects, they wouldn't necessarily cause the continuous discharge and particular pressure readings described in this situation as effectively as debris in check valve number 1 does.