A drain valve for a vehicle compressed air system, which separates dirt, water, debris and other relatively heavy objects from a compressed air stream. The drain valve includes a sump with a tangential inlet. The tangential inlet creates a vortex within the sump that collects relatively heavy objects at the bottom of the sump and allows the compressed air to exit the drain valve through an outlet port located at the top of the drain valve. A pressure actuated valve and drain port allows for the water to be discharged from the drain valve while retaining the pneumatic signal.