What other component must be installed with a double check assembly when installed below grade?

What other component must be installed with a double check assembly when installed below grade?

• A. Check valve
• B. Air vent
• C. Isolation valve
• D. Wye strainer

Answer: (D)

When a double-check backflow assembly is installed below grade, debris and sediment in the supply line can be drawn into the device and clog the valves or damage seats, and maintenance access is limited. Placing a wye (Y) strainer upstream of the assembly provides filtration, catching sediment before it reaches the backflow preventer. The strainer’s screen is easy to clean via its drain without removing the backflow, helping protect the device and keep it functioning properly in an underground install. The other options aren’t specifically required as a companion component for underground DCVA installations.

When a double-check backflow assembly is installed below grade, debris and sediment in the supply line can be drawn into the device and clog the valves or damage seats, and maintenance access is limited. Placing a wye (Y) strainer upstream of the assembly provides filtration, catching sediment before it reaches the backflow preventer. The strainer’s screen is easy to clean via its drain without removing the backflow, helping protect the device and keep it functioning properly in an underground install. The other options aren’t specifically required as a companion component for underground DCVA installations.