TM 10-4610-232-34
Table 2-1. Direct Support Troubleshooting Guide (continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
6.
(c) Repair any loose or damaged wires (para. 2-20).
(d) If the above checks have not revealed the problem, refer to generator troubleshooting.
Step 3. Shut down ROWPU and generator. Refer to electrical drawings in Appendix D. Check continuity, point-to-
point, from the power distribution block (PDB) to J21 (REF: Interconnection diagram FO-2, Sheet 16) on the
following lines: AL1 to J21E, AL2 to J21F and AL3 to J21G. Depress the operating plunger on MS3 (REF:
Interconnection diagram FO-2, Sheet 10) when checking across its contacts. Disconnect the J21 connector
when testing.
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 an MS3 overload shows open, replace it and continue troubleshooting (malfunction 2) to find cause
(para. 2-25).
(d) If MS3 shows open on any phase, replace/repair it (para. 2-25).
(e) Replace/repair J21 if faulty (para. 2-21 ).
(f) Refer to raw water pump mechanical troubleshooting (malfunction 3).
Raw water pump will not start in system backwash. (Ref. Schematic diagram FO-1, sheet 1, schematic line 163).
Step 1. Shutdown the ROWPU. Open the control panel. Power up the unit, set the control panel up for backwash and
push initiate, There will be a delay as the media filter drains down and the pressure comes down. The delay
time is dependent on how much water and pressure is in the media filter. After the drain down, the indicating
plunger on relays K11 and K13 (REF: Interconnection diagram FO-2, Sheet 6) will pull in and the raw water
pump should start.
If either relay does not pull in, refer to media filter backwash troubleshooting.
Step 2. Shutdown ROWPU and generator. Refer to electrical drawings in Appendix D and remove the #230 wire from
relay K12(A1Y) (REF: Interconnection diagram FO-2, Sheet 6). Check continuity, point-to-point, from
PB6(1B1) and PB7(1A4) (REF: Interconnection diagram FO-2, Sheet 11) to the end of the disconnect wire
#230. Depress the indicating plunger on K13 when testing across its contact.
(a) Repair any loose or damaged wire (para. 2-20).
(b) Replace relay K13 if its contact does not show continuity when the plunger is depressed (para. 2-23).
Raw water pump circuit breaker open whenever the pump is started, ROWPU shuts down when the raw water pump is
started. (Ref. Schematic diagram FO-1, sheet 5, schematic lines 532-533).
Check for short circuits.
(a) Shut down ROWPU and generator.
(b) Refer to electrical drawings in Appendix D.
(c) Refer to raw water pump will not start troubleshooting (malfunction 1, step 12).
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