Table 2-1. Direct Support Troubleshooting Guide (Continued)
TEST OR INSPECTION
(b) Repair starter MS8-1M if its contact is closed with the pluinger out or if it is open when the plunger is
depressed (para. 2-25).
(c) Return the ROWPU to service and check phase 1 of the backwash cycle.
Step 9. Open the media filter top drain valve and watch that the media filter pressure drops below 5 psig. Check that
the indicating plunger on relay K15 is out.
If the plunger on K15 is in, refer to feed low pressure switch troubleshooting.
Step 10. Watch the level assembly on the media filter. It should turn white as the water level drops in the media filter.
Relay K10S (REF: Interconnection diagram FO-2, Sheet 6) indicating plunger should go in when the white
flags reach the bottom switch on the level assembly. Relay K11 should pull in shortly after K10 pulls in. (The
time delay between K10 and K11 is dependent on how much pressure is in the filter. If PSL8 (REF:
Interconnection diagram FO-2, Sheet 14) is still sensing pressure, it will keep K11 de-energized until the
pressure drops low enough to allow the switch to close.)
(a) If the flags do not turn white on the level assembly and water has stopped draining from the media
filter top drain, refer to media filter level assembly plugged troubleshooting in TM 10-4610-232-12.
(b) If K10 does not pull in and the water level has reached the bottom switch on the level assembly
(actuation point is midway through the switch), go to step 11.
(c) If K10 pulls in but K11 does not, go to step 18.
Step 11. Shut down ROWPU and generator. Refer to electrical drawings in Appendix D. Disconnect connector at the
bottom switch of the media level assembly. Check continuity across J35A (REF: Interconnection diagram
FO-2, Sheet 15) and J35B.
If there is continuity, go to step 14.
Be careful when removing the float. It will drop out when the cover is removed from the
Step 12. Remove the bottom of the level assembly and remove the float. Check for continuity across J35A and J35B
with the float removed.
(a) If there is continuity, the float is not dropping far enough to actuate the switch. Clean out anything
plugging the lines to the level assembly and clean out the level chamber.
(b) If there is nothing plugging the lines or chamber, it is possible that the switch is loose and slipped
slightly out of position, Move it up the chamber a little and go to step 13. Do not tighten the switch
clamp too tight, it will crack from overtightening.
Step 13. Check that J35A and J35B show continuity and insert the float into the level chamber with the arrow up.
Slowly push it up the chamber and watch the multimeter. It should show the switch opening as the float goes
past it and stay open. Slowly let the float drop and watch that the switch closes as the float goes by it. It should
then stay closed.
(a) If the switch (LSLL) (REF: Interconnection diagram FO-2, Sheet 15) does not operate as described,
replace it (para. 4-52 of TM 10-4610232-1 2).
(b) Return the ROWPU to operation and check phase 1 operation.
Step 14. Reconnect J35 and remove P16 (REF: Interconnection diagram FO-2, Sheet 15) from the control panel.
Check for continuity across P16T and P16U.
If there is no continuity, replace/repair the cable and connectors between the panel and the LLSL switch
Step 15. Check continuity, point-to-point, from LK1 (SW2) (REF: interconnection diagram FO-2, Sheet 6) to J16T.
Repeat the procedure from LK1 (SW1) to J16U.
(a) Repair any loose or damaged wire (para. 2-20).
(b) Replace/repair connector J16 if faulty (para. 2-21).
Step 16. Remove wire #2A from K10. Check continuity, point-to-point, from CB9 (wire #264) to LK1(AC) and from
LK1(LOAD) to relay K10(K1). Check continuity, point-to-point, from transformer T1(X2) (REF: Interconnec-
tion diagram FO-2, Sheet 10) to relay K10 (wire #2A).
Repair any loose or damaged wire (para. 2-20).