Cross Connection Practice Exam

How is the pressure differential maintained in a Reduced Pressure Principle Backflow Assembly?

1. Through an external hydraulic source

2. By gravity flow

3. By the action of check valves

4. Using a pressure gauge

The correct answer is: By the action of check valves

The pressure differential in a Reduced Pressure Principle Backflow Assembly is maintained by the action of check valves. This type of backflow prevention assembly consists of two check valves that work in tandem to create a pressure differential. The first check valve is situated in the direction of the flow, allowing water to pass normally while preventing any backflow into the supply line. The second check valve is positioned downstream and is subjected to the pressure from the supply line and atmospheric pressure from the downstream side. When there is a drop in pressure on the downstream side (due to potential backpressure or backflow), the first check valve closes to prevent contaminated water from flowing back into the clean water supply. Simultaneously, the difference in pressure between the two sides of the second check valve creates a maintained pressure differential that ensures the system functions properly. This method of using check valves is crucial for the backflow prevention system, providing an effective barrier against cross-connections and safeguarding potable water supplies. Other options involve differing mechanisms or sources that do not directly support the function of pressure maintenance in this specific assembly type.