The D-060 NS series Combination Air Valve has the features of both
an air release valve and an air & vacuum valve.
The air release component is designed to automatically release small
pockets of air to the atmosphere as they accumulate along a pipeline
or piping system when it is full and operating under pressure.
The air & vacuum component is designed to automatically discharge
or admit large volumes of air during the filling or draining of a
pipeline or piping system. This valve will open to relieve negative
pressures whenever water column separation occurs.