Mechanical Connections; Fuel System - Onan DFE Series Installation Manual

Mechanical Connections
The generator set mechanical: system instaUation
includes connecting the fuel, exhaust, ventilation and
cooling systems. Before starting any type of fuel installa-
tion, Onan recommends alii pertinent state and local
codes be complied with and: the installation must be
inspected before the unit is put in, service. -
FUEL SYSTEM
Cummins engin es used on the DF series gen erator sets
normally use ASTM No. 2 Diesel fuel. They will, how-
ever, operate orv dcesel fuels within the speeificattons
delineated in the. Cummins engine manual.
General
In all fuel system tnstaiFattons, cfeantrness is ot the
utmost importance;. Make evety effort to prevent en-
trance *of moisture,, dirt or contaminants of any kind.
Clean all fuel system components before installing.
Use only compatibfe.metaf tuet lines to avofdelectroly-
sis when fuel lines; must be buriedL Never use gafwart.-
ized or copper fuel; tines or fittings wtth diesef fuel as it
tends to flakeo.ff and eortfaminate the fuel. Useaflexibte
section of tubing; between, the engine and fuel: supply
line to withstand.vibration.
ACAUTIOt*
Never use galvanized or copper fuel
lines,, fittings oriuettanks wit ft diesel
fuel systems. Condensation in the tank and lines com-
bines with the sulfur in diesel fuel to produce suffuric
acid. The molecufar structure of the copper or galvan-
ized lines or tanks reacts with the, acid and contami-
nates the fuel.
An electric solenoid shutoft vatve in the supply line is
always desirabfe and! requtred! for indoor automatic, or
remote startmg instalfettors. Connect the sotenotd
'-wires to the battefy igpitioni ctreuit to open the valve
during generator set operation.
Supply Tank
Locate the fuel tank as close as possible to the genera-
tor set and within; theSfoot (1.5 metre} lift capacity ofthe
fuel pump if possiibfe. Choose a tank that has sufficient
capacity to keep thegenerator mnning. continuously at
full load for at least 36 hours.
AWARNING
Fuel teaks create fire and explosion
hazards which can result in severe:
personal injury or death. Always use flexible tubing
between engine andthe fuel supply to avoid line failure
and leaks due to vibration. The fuel system must meet
applicable codes.
A typical underground fuel system consists of a main
fuel tank, vent and fill pipes, fuel supply line, and fuel
return line (see Figure 1). Ifthe tank is installed below the
lift capabilities ofthe standard fuel transfer pump, a day
tank and auxiliary pump will also be required. If an*
overhead tank is installed, a day tank and float valve will
be required to prevent fuel head pressures from being
placed on thefuel system components. Referto Techni-
cal Bulletin T-030 for examples of fuel supply systems
that require a day tank.
Day Tank (If Used)
Day tanks are fuel transfer tanks which aroused when
the standard engine fuel pump does not have the capac-
ity to draw the fuel from: the supply tank; or the supply
tank is overhead and presents problems of high fuel
head pressure for the fuel return. See Figure 3.
FUEL PUMP RETURN LINE
(jF USED);
INJECTOR,
FUEL RETURN-
LINE
Alii models require fueh return- line!
from injectors to tank.
. f l -
FLOAT TYPE.SWITCH
CONNECT TO
AC OUTPUT ' " V
VENT LINE
/
'DAY' TANK
25 GAL. (20 LITRE)
MINIMUM CAPACITY
FUEL TRANSFER
PUMP - ELECTRIC
MOTOR DRIVEN
LARGER
OVERFLOW
UNE
SUPPLY/
LINE
FILL
PIPE
l l
11
l i
11
I I
11
UNDERGROUND
It
11
1 •
FUEL TANK
11
u
ES-1214-1
F I G U R E 3. DAY TANK ( T Y P I C A L )