Table 2-7. UNIT CENTRIFUGAL PUMP UNIT TROUBLESHOOTING PROCEDURES
TEST OR INSPECTION
CENTRIFUGAL PUMP UNIT FAILS TO START.
Step 1. Check for continuity on power cable.
Remove electrical power from water heater, refer to TM 10-4520-259-13&P.
Remove power cable from centrifugal pump unit and water heater.
Using a multimeter, check power cable for continuity between the following connectors:
(1) X to X
(2) Y to Y
(3) Z to Z
(4) G to G
If no continuity exists, refer to Direct Support.
Step 2. Check for continuity on centrifugal pump unit electrical receptacle connector and connector-switch.
Remove cover on electrical receptacle connector and connector-switch.
Using a multimeter check for continuity between the following connectors:
(1) X to L3
(2) Y to L1
(3) Z to L2
If no continuity exists on one wire, repair wiring per FO-5, Centrifugal Pump Unit Wiring Diagram.
Step 3. Check for continuity on connector switch.
Set connector switch to ON.
Using a multimeter check for continuity on connector switch between following contacts:
L1 to T1
L2 to T2
L3 to T3
c. If no continuity exists on one contact, replace connector switch (Para 2-76, Connector-Switch.
If continuity exists, set toggle switch to OFF.