FASS T D07 150G - Manual (Page 15)

Fuel Filter –Install FWS-3003 on
side of pump with draw tube in
the middle of the filter nipple.
Water Separator Filter –Install FS-1001 on water separator
nipple without the draw tube. Make sure to insert O-Ring
provided on nipple.
Note: O-Ring must be put back on suction side of pump.
Failure to do so can result in priming issues, cavitation, or
pressure loses.