TM 10-4610-232-34
Table 2-1. Direct Support Troubleshooting Guide (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
NOTE
When checking continuity in the power circuits it is important to watch the wire numbers
on each phase. Each wire is tagged identically on both ends, but in some instances, a #1
phase wire will enter the top of a starter or circuit breaker and come out the bottom of the
same device as a #2 phase wire. This is done to change the rotation of a motor so that its
associated pump will turn in the correct direction. Any two wires may be interchanged to
accomplish this rotational change.
(a) Repair any loose or damaged wire (para. 2-20).
(b) Replace circuit breaker CB4 (REF: Interconnection diagram FO-2, Sheet 10) if open on any phase
(para. 2-25).
(c) If MS3 shows open on any phase, replace/repair it (para. 2-25).
(d) Replace/repair J21 if faulty (para. 2-21).
Step 13. Shut down ROWPU and generator. Disconnect the cable from the ROWPU to the generator at the generator
end. Check continuity, point-to-point, from the generator end of the cable to the power distribution block
(PDB) on each phase.
(a) Replace the main power cable if open on any phase (para. 2-18).
(b) Replace circuit breaker CB1 (REF Interconnection diagram FO-2, Sheet 10) if open (para. 2-25).
(c) Repair any loose or damaged wires (para. 2-20).
(d) If the above checks have not revealed the problem, refer to generator troubleshooting.
2. Raw water pump overload heaters burned out. (Ref. Schematic diagram FO-1, sheet 5, schematic lines 532-537).
Check each lead, 2T1, 3T2 and 3T3 from the outlet side of MS3 (REF: Interconnection diagram FO-2, Sheet 10) to
connector J21 (REF: Interconnection diagram FO-2, Sheet 16) for tightness and damage.
(a) Repair any loose or damaged wire (para. 2-20).
(b) Repair the terminal strip if damaged (para. 2-23).
(c) Repair connector J21 if damaged (para. 2-21).
(d) Replace the MS3 overload heaters (para. 2-23).
3. Raw water pump starts but stops when start button is released. (Ref. schematic diagram FO-1, sheet 6, schematic lines
619-620).
Step 1. Shut down the ROWPU. Open the control panel. Refer to the operator’s manual and restart the unit. Look at
the indicating plunger on relay K1 (REF: interconnection diagram FO-2, Sheet 6). It should be in. If it is out,
refer to operation mode circuit troubleshooting.
Step 2. Shutdown ROWPU and generator. Refer to electrical drawings in Appendix D. Check continuity, point-to-
point, from PB7(1A4) to PB7(1A3) (REF: Interconnection diagram FO-2, Sheet 11) and K12(A1Y) (REF:
Interconnection diagram FO-2, Sheet 6). Depress the indicating plunger of MS3 (REF: Interconnection
diagram FO-2, Sheet 10) and K1 when checking continuity across their contacts.
(a) Repair any loose or damaged wire (para. 2-20).
(b) Replace relay K1 if its contact does not show continuity when the indicating plunger is depressed
(para. 2-23),
(c) Replace/repair MS3 if its contact does not show continuity (para. 2-25).
4. Raw water pump motor hums but will not turn. (Ref. Schematic diagram FO-1, sheet 5, schematic lines 532-533).
Step 1. Check with operator.
(a) If other motors do not operate, go to step 2.
(b) If other motors operate okay, go to step 3.
Step 2. Shutdown ROWPU and generator. Disconnect the cable from the ROWPU to the generator at the generator
end. Check continuity, point-to-point, from the generator end of the cable to the power distribution block
(PDB) on each phase.
(a) Replace the main power cable if open on any phase (para. 2-18).
(b) Replace circuit breaker CB1 (REF: Interconnection diagram FO-2, Sheet 10) if open (para. 2-25).
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