Floscan Pre-Installation Manual for Diesel Models - Manual (Page 7)

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• Pressure drops across standard fittings can be more than SIXTEEN (16) times higher than those across full-flow fittings,
and higher still across medium and high-pressure fittings.
Fuel Return Lines
Pressure drops across the fuel return line are not as critical as those on the inlet line. Using good system practice, plumb the
return system so that fuel flow velocities go no higher than 10 feet per second.
Hose Barb Fittings
Thin wall full flow hose barb fittings are designed to accommodate “FULL PIPE-SIZE FLOW” and provide unrestricted
passage through the fitting. To achieve this and to maintain adequate wall strength, the hose barb end of the fitting is one size
larger than the pipe thread end.
Reducer bushings, pipe nipples, and couplings may be required to connect the pipe thread end of the hose fitting to other
system components, (Sensor, Pulsation Damper, Racor Filter, and Lift Pump). Though non-full flow standard fittings with
the correct size pipe thread end are more convenient, they increase flow resistance considerably. Pressure drops exceeding 1
PSI per fitting are not uncommon. Properly sized full flow fittings have less than a 0.1 PSI pressure drop.
Barb-Tite, Push-Lok, and similar hose fittings which don’t require hose clamps, have thick walls and relatively small inside
diameters. They are good fittings, and can be used on the return line. If used on the forward line you may have to up size to
the next larger hose and fitting to avoid excessive pressure drops.
Swivel Fittings
There are 3 types of swivel fittings in common use.
1. 37 degree JIC, (Joint Industrial Congress) fittings.
2. 45 degree SAE, (Society of Automotive Engineers) fittings.
3. M-UFS & F-UFS, (Male or Female, Universal Female Swivel) pipe thread fittings, and pipe unions.
J.I.C, and S.A.E. swivel fittings are usually rated for medium and high-pressure applications. Their walls are considerably
thicker than, “Reusable” clamp or band type, low pressure, full flow hose barb fittings. If used on the forward fuel flow line,
you may have to up size to the next larger hose and fitting to avoid excessive pressure drops. UFS fittings and pipe unions
should not be used on marine fuel systems.
If J.I.C. or S.A.E swivel fittings are used, their mating surfaces must be sealed with Copper Conical Sealing Washer, (Connie
Seals). Connie seals may be purchased through Fittings Inc. in Seattle, WA
(206) 767-4670, 1-800-552-0632, or any hydraulic supply house.