TM 10-6640-233-10 Table 2-10. Water System Control or Indicator Function 1.  Pressure Switch Starts/stops water pump at desired pressure. 2.  Pressure Regulator Controls/regulates    water    pressure    to    service outlets. 3.  Tank/System Switch Controls flow to tank and system. 4.  Filter Valve Switch Directs flow to filters or isolates flow from filters. 5.  Pump/Suction Valve Controls   external   source   water   flow   to   pump suction port. 6.  Tank Pump Valve Controls flow of water from tank to pump. 7.  Tank Bubble Indicator Indicates water level in the water tank. 8.  Tank Drain Valve Tank drain located on tank. 9.  Bubble Level Isolation Valves Isolates level indicator from tank. 10.  Water Flow Facility Supply Switch Directs water flow to system or filters. 11.  Filter Reservoir Drain Valve Drains system water to external (outside) receiving facility/container. 12.  Exterior Tank Drain Valve Drains  tank  water  to  external  (outside)  receiving facility/container. 2-13