Table 4-2. Unit Troubleshooting Guide (Continued)
TEST OR INSPECTION
Media filter is plugged and water will not flow through it.
This typically would only happen in a cold weather situation where the filter has not
been drained properly and then frozen.
Check media filter for ice build up.
Apply heat to filter until ice melts.
Media filter wont drain.
To prevent injury to personnel, relieve all pressure on filter before proceeding.
Step 1. Check drain valves.
Remove valves and clean the insides. Clean out piping that attaches to valves (para. 4-53).
Step 2. Check vent valve.
Remove valve and clean out the inside. Clean out the tubing and fittings that attach to the valve (para.
Media filter depth is low.
Add additional media (para. 4-53).
1. Cartridge filter outlet turbidity same as inlet turbidity.
Step 1. Check filter vessel bottom plate for cracks.
Replace filter if cracks are found (para. 4-44).
Step 2. Check for loose filter seats on the bottom plate.
Replace the cartridge filter vessel if loose seats are found (para. 4-44).
Step 3. Check media filter outlet turbidity with portable turbidity meter at item 4, Table 2-5. If reading is 0.5-2.0
NTU, particles may be too small for cartridge filtering.
Replace the cartridge filter if the inlet turbidity is greater than 4 and the outlet is the same (para. 4-44).
2. Large or sudden amount of media in the cartridge filter.
Step 1. Remove and check media filter inlet valve for blockage (para. 4-45).
Clean out the four holes in the valve disc (para. 4-47).
Step 2. Check operation of "NORMAL" and "BACKWASH" cycles.
(a) Clean the media out of the cartridge filter and operate unit in "NORMAL" and "BACKWASH"
If there is little or no media in the cartridge filter, have the operators monitor future operation as a
check to see that it does not reoccur.
(b) If after the above operation, there is a large amount of media in the cartridge filter, notify direct
support maintenance to replace media filter.
3. CARTRIDGE FILTER PLUGGED light is on at a differential pressure less than 12 psi (83 kPa), or, is not on and the
differential pressure is greater than 20 psi (138 kPa).
Operate the unit and determine that malfunction is true.
Notify direct support maintenance to troubleshoot cartridge filter differential switch circuits.