Perform BEFORE operation PMCS.
Slowly open air vent valve by pushing in and turning until the handle is engaged in the slot.
Make sure that water drain valve is closed.
Start the system pumping unit.
Open external up-stream valve slightly to fill the filter/separator slowly with as little pressure as
When vessel is completely filled fuel will begin to come from the vent valve. Close vent valve and
make a visual inspection for leaks.
Fully open any down-stream valve and then fully open up-stream valve to begin fuel pumping
Perform DURING operation PMCS.
If differential pressure indicates in the RED PORTION, STOP OPERATION IMMEDIATELY and notify
unit maintenance. If gage indicates in yellow, refer to Table 3-1.
If ball in sight gage reaches the mark on gage body, open manual drain valve to drain water.
b. Fuel Sampling.
(1) It is mandatory that the performance of filter/separators on all aircraft refueling equipment be checked
every 30 days through the submission of samples taken from the effluent stream of the
(2) The adapter attached to the filter/separators outlet coupling contains a sampling probe, which
extends into the fuel flow. A Detector Kit, NSN 6640-00-244-9478, can be attached to the sampling
probe to obtain fuel samples.
For disposal of contaminated fuel, refer to FM 10-20.
(1) Stop the system pumping unit.
(2) Close the up-stream and down-stream valves to isolate the filter/separator from the system.