Preaction System Double Interlock Electric/Pneumatic Release

When the detector (1) is activated, a signal is sent to the VFR-400 release control panel (2). The panel sends appropriate alarm signals, and at the same time, signals the release of the solenoid valve (3). The deluge valve will NOT open until a sprinkler (4) opens. When a sprinkler opens, supervisory pressure in the sprinkler piping is reduced causing the pneumatic actuator (5) to open. After BOTH the electric detection system activates AND supervisory pressure in the sprinkler system have been lost, pressure is released from the priming chamber (6) of the deluge valve, allowing the valve to open. When the deluge valve operates, pressure opens the pressure operated relief valve (PORV) (7)continuously venting the water to the priming chamber, ensuring the deluge valve remains in the open position.