TM 10-6640-239-13 2-17 h. Water System Controls and Indicators.  Figure 2-9 and Table 2-9 list the controls and indicators for the water system. Table 2-9.  Water System Controls and Indicators Index Number Control or Indicator Function 1 Water Pump ON/OFF Controller Energizes motor start/stop circuit at pressure switch. 2 Pressure Switch Starts and stops water pump automatically at required pressures. 3 Water Pressure Gauge Indicates water pressure maintained by water pump during operation. 4 Water System Service Valves (Supply) Provides system service access to water system in MBPL.  Three supply valves are located on the roadside, one in each fume hood and four on the curbside. 5 Water System Service Valves (Return) Provides system service access to water system in MBPL.  Three return valves are located on the roadside, one on the curbside and one in each fume hood. 6 Pump Suction Valve from Water Tank Bottom Isolates water to water pump. 7 Water Supply Chiller Isolates water supply to chiller. 8 Main Water Feed from Pump Isolates water from water pump to system lines. 9 Water Flow Direction Provides water flow direction to system. 10 Pump Suction Tank Fill Provides directional path of water flow to either the water pump or water tank. 11 Input Valve Postfilter Isolates water from water filter. 12 Input Valve Prefilter Isolates water to water filter. 13 Return Water Drain Provides drainage of water return lines. 14 Water System Drain Provides drainage of water system lines. 15 Water Tank Drain Provides drainage of water tank. 16 Filter Backwash Provides drainage to backwash filter. 17 Water Pump Drain Provides drainage of water pump. 18 Pump Suction Drain Provides drainage of pump suction line from water tank bottom. 19 Chiller Water Return Provides drainage of water chiller. 20 Water Supply Drain Provides drainage of water supply line to laboratory. 21 Sump Tank Drain Provides drainage of sump tank. 22 Hot Water Tank Supply Drain Provides drainage of water supply line to hot water tank.