2" Model F-1 Deluge Valve, Pretrimmed, Threaded The Viking Model F-1 Deluge Valve is a quick opening, differential diaphragm, flood valve with one moving mechanism. The Deluge Valve is used to control water flow in Deluge and Preaction sprinkler systems. The valve is held closed by system water pressure trapped in the priming chamber; keeping the outlet chamber and system piping dry. In fire conditions, when the releasing system operates, pressure is released from the priming chamber. The Deluge Valve clapper opens to allow water to flow into the system piping.