Abstract: A four-way air directional valve assembly is disclosed in combination with apparatus employed for pneumatically generating waves in a wave pool having a plurality of wave generating chambers arranged side-by-side and extending across the width of a pool at one end thereof. Each of these wave chambers has a below the water passageway in communication with the pool and a sealed portion located above the normal water level of the pool. Each chamber has an inlet-outlet passageway above the water level with the passageway serving in one mode as an inlet for directing forced air into the wave chamber and in a second mode as an outlet for exhausting air therefrom.