TM 10-4610-232-12
Table 3-1. Operator Troubleshooting Guide (Continued).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
11. Media filter output turbidity is greater than 5 NTU.
Step 1.
Check turbidity monitor.
Refer to para. 2-5 for adjustment and crosscheck using the hand held turbidity meter para. 2-6.
Step 2.
Check polyelectrolyte flow.
Watch that level in polyelectrolyte tank drops consistently.
Step 3.
Vigorously stir the polytank to ensure mixing.
Step 4.
Repeat polyelectrolyte optimization.
Refer to para. 2-17f.
Step 5.
Backwash media filter.
Refer to para. 2-21.
Step 6.
Check filter media depth.
a. Shut down to temporary shutdown condition.
b. Open media filter vent and both drains.
c. When water no longer is observed at upper drain, close drain valves and open filter access port.
d. Use steel rule and measure down to media level. If more than 14 inches (356 mm) but less than 17" (432
mm), contact unit maintenance to add media.
Step 7.
Recondition media.
NOTE
Media can become fouled with organic material which will lead to channeling and poor
filtration. Make sure that chlorine is being pumped into filter during backwash.
a. Backwash and allow automatic steps to proceed up to taking water from the clean/flush tank. Switch the
OPERATION MODE switch to FILTER NORMAL and push INITIATE.
b. Repeat step a. after air pressure has built up.
c. Allow filter to soak for 2 hours.
NOTE
Diesel generator may be secured if the feed valve and cartridge filter block valve are first
closed.
d. Backwash again (step a) and repeat 2 hour soak.
e. Backwash normally, allowing a complete backwash sequence (para. 2-21).
f. Return to normal operation.
Step 8.
Contact unit maintenance to replace media.
12. Media filter pressure drop exceeds 15 psig (69 kPa) after backwashing.
Step 1.
Repeat backwash.
Step 2.
Recondition media.
Refer to malfunction 11, step 7 above.
Step 3.
Contact unit maintenance to replace media.
13. Media filter inlet and outlet pressure are equal during normal operation.
Step 1.
Ensure cleaning bypass valve (V13) is closed.
14. Drain sump has media in it (or sump hose has media coming out).
NOTE
This situation is typical when the media filter has been manually drained to initiate a
backwash. The media ends up in the sump because the upper drain valve has not been
closed fast enough when the raw water pump is turned on at the start of backwash.
Step 1.
Refer to air blanket troubleshooting, problems 5, 6, and 7 and also backwashing, problems 3 and 15.
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