TM 10-6640-215-13 Table 3-2.  Troubleshooting - continued MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 17. VACUUM PUMP FAILS TO RUN WHEN START BUTTON ON MOTOR CONTROLLER IS DEPRESSED. Check and reset circuit breaker A15CB9 located in POWER PANEL NO.  2. If vacuum pump still fails to run, notify unit maintenance. 18. VACUUM PUMP FAILS TO DEVELOP A VACUUM (MOTOR RUNNING). Check for broken or loose drive belt. Replace or tighten belt as required in accordance with TM 10-4310-391-13&P. 19. LOW VACUUM PRESSURE. Step 1. Check for open valves in the system. Close all valves. Step 2. Check for leaks in the system. If leaks are found, notify unit maintenance. 20. WATER PUMP FAILS TO RUN WHEN ON/OFF CONTROLLER SWITCH IS ON. Step 1. Check operation of controller ON/OFF switch. Step 2. Check and reset circuit breaker A15CB8 located in POWER PANEL NO.  2. If motor still fails to run, notify unit maintenance. 21. WATER PUMP FAILS TO DELIVER WATER AT PROPER PRESSURE. Step 1. Check level in water tank. If level is low, fill water tank. Step 2. Check for leaks in the system valves, piping and at the pump shaft seal. If leaks are found, notify unit maintenance. Step 3. Check for dirty filter. If filter is dirty, backflush filter. 3-8