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Electrical Maintenance
93
4. The UFLS assembly should be pre-assembled
before installing it into the fuel tank.
a. Slide a gasket up the sensor tube to the
flange, making sure the pin hole in the
gasket is centered between the two
mounting holes next to the notch as shown
in Figure 158.
b. While holding the lower gasket in place,
place the upper gasket onto the sensor tube
flange, again making sure the pin hole in
the gasket is positioned between the two
mounting holes next to the notch as shown
in Figure 158.
c. Place the sensor on top of the upper gasket
with the harness pointing towards the
notch on the sensor tube flange. All holes
should now be aligned.
d. Install the 10-32 screws, lock washers and
flat washers onto the sensor and through
the gasket holes to hold the assembly
together.
Installation In Tank
5. Insert assembly into fuel tank making sure the
notch on the sensor tube is aligned with the
notch on the tank flange. When installed
correctly, the sensor harness will be pointed
towards the fuel fill on the end of the tank.
Hand tighten the five mounting screws in a
criss-cross pattern and torque them to 10-15
in-lbs (1.1-1.7 N•m).
DO NOT overtighten the mounting hardware
or damage to the plastic sensor will result.
The fuel tank is now ready to be reinstalled.
Wire Connections
6. Cut the sensor cable wires (or old sensor
wires) to the appropriate length and splice
them to the new sensor wires using solder
connectors (P/N 41-5210) and heat shrink
tubing (P/N 92-846) as follows:
IMPORTANT: DO NOT burn the heat
shrink. If the heat shrink is burnt, charred,
or has bubbles from overheating, the wire
connections must be removed and redone
correctly.
Electric Fuel Heater (Optional)
An electric fuel heater is optional equipment on
these units.
Operation
The electric fuel heater has an internal thermostat
that closes at 30 F (-1 C) minimum, and opens at
75 F (24 C) maximum.
When the unit is turned On (and SmartPower
units are in Diesel Mode) and is running, the 8FH
circuit is energized. This energizes the Fuel
Heater Relay and closed its contacts.
With the relay contacts closed, the 2A circuit
provides power to the fuel heater, which will heat
up if its internal thermostat is closed. The current
through the fuel heater is 11.4 to 13.9 amps at 12.5
Vdc.
NOTE: The electric fuel heater does not
function when the unit is in the Electric Mode
(electric standby operation), the Null Mode, or
during the non-running portion of the Pretrip
Test.
Components
The main components of the electric fuel heater
option are listed below.
•
Electric Fuel Heater
•
Mounting Bracket and Hardware
•
Fuel Heater Harness (includes the following)
•
Fuel Heater Relay
•
2FH/2HP Fuse (20 amp)
The electric fuel heater is mounted next to the fuel
filter as shown in Figure 159. The inlet line to the
fuel filter is moved to the electric fuel heater inlet.
A short fuel line is added between the electric fuel
heater outlet and the fuel filter inlet. The relay and
fuse are mounted inside the control box.
Sensor Cable Wire
Sensor Wire
Green
Red
White
Yellow
Black
Black