The 106-A-Type 2 and 206-A-Type 2 altitude control valves are based on the 106-PG and 206-PG main valves and are ideal for maintaining a preset maximum water level. Each valve functions as a two-position control valve—either fully open or fully closed. The Type 2 valves allow normal forward flow to fill the reservoir to the maximum level and then closes drip-tight at the set point. They open to refill the tank once the level drops a fixed distance below the high water level.