TM 10-6640-215-13 Table 4-2.  Troubleshooting - continued MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 19. WATER PRESSURE SWITCH FAILS TO OPERATE PROPERLY. Step 1.      Check that electrical power is available at the switch. Step 2.      Adjust the switch.  Refer to TM 10-4310-391-13&P. If pressure switch still fails to operate properly, replace the switch.  See paragraph 4-39. 20. WATER CHILLER FAILS TO PRODUCE CHILLED WATER (POWER AVAILABLE). Troubleshoot  in  accordance  with  TM  10-  4130-240-13&P.    If  problem  cannot  be  resolved,  notify  direct  support maintenance to replace water chiller. 21. WATER HEATER FAILS TO PRODUCE HOT WATER (POWER AVAILABLE). Check water input/output valve line up. If valve line up is correct, notify direct support maintenance to replace water heater. 22. SUMP PUMP FAILS TO OPERATE (POWER AVAILABLE). Troubleshoot pump in accordance with TM 10-4320-320-13&P.  If problem cannot be resolved, notify direct support maintenance to replace sump pump. 23. GAS ALARM SYSTEM FAILS TO OPERATE OR OPERATES IMPROPERLY. Step.  1 Calibrate system in accordance with TM 10-6665-297-13&P. System will not calibrate or adjust. Step 2. Troubleshoot system in accordance with TM 10-6665-297-13&P. If problem cannot be resolved, replace detector element and/or alarm control unit. See paragraph 4-40. 24. GUM BATH FAILS TO OPERATE PROPERLY (POWER AVAILABLE). Troubleshoot  gum  bath  in  accordance  with  TM  10-6630-234-13&P.    If  problem  cannot  be  resolved,  notify  direct support maintenance to replace gum bath. 4-17