What is a key difference between a Pressure Vacuum Breaker (PVB) and a Double Check Valve Assembly (DCVA)?

The correct choice draws attention to the installation requirements of the Pressure Vacuum Breaker (PVB) and the Double Check Valve Assembly (DCVA), which are critical for their effective operation in irrigation systems. A Pressure Vacuum Breaker must always be installed above ground to function correctly, as it relies on gravity to prevent back-siphonage by utilizing an air intake to break a vacuum when negative pressure occurs. This feature safeguards the water supply from contamination.

On the other hand, a Double Check Valve Assembly can be installed below ground, which is suitable for locations where above-ground installation is not feasible or desirable. Unlike the PVB, the DCVA does not have the same air-gap requirement to prevent backflow, allowing for its underground placement. This distinction in installation guidelines reflects the specific applications and functional designs of these devices. Understanding these operational and physical characteristics helps ensure proper system setup and compliance with plumbing codes.