23
en
4. Start the engine. See ‘Starting The Engine’.
The Heater Unit
The heater trailer is equipped with two indirect fired electroni-
cally controlled heater units. Each heater unit can be started
independently of the other. One or both heater units can be
used.
The basic operation of an indirect fired heater unit is as fol-
lows:
The burner draws fuel from the fuel tank, and pressurizes it
so that it can be atomized at the nozzle into the combustion
chamber. Air is blown into the combustion chamber to mix
with the fuel and ignited, thereby heating the combustion
chamber. The large fan above the burner blows air over the
combustion chamber to cool it and transfers the heated air
to the heater outlet. Exhaust gases are kept separate from
the heated air and are vented through the chimney. A series
of sensors ensures that the combustion chamber does not
overheat, and shuts down the unit automatically should the
temperatures get too high.
To operate most efficiently, the air flow and fuel flow must
be controlled to maintain the proper air / fuel mixture. Fuel
flow is controlled by the nozzle, and air flow is controlled by
means of a damper. If the mixture is too rich (too much fuel),
large amounts of smoke and soot will be exhausted from the
chimney, fuel will be wasted, and the maximum heated air
temperature may not be reached.
The heater units in the heater trailer are each equipped with
an electronic control module (A, Figure 20). The control
module regulates the heated air temperature, controls the
burner, senses barometric pressure and ambient temperature
and calculates the damper setting. A display is provided on
the control module.
Figure 20
A
Providing Electrical Power To The Heater Unit
The heater trailer is equipped with an engine / generator set
to power the heater units. However, the heater units may be
powered by other electrical means at the job site.
Should you choose to use electric power from other than the
heater trailer’s engine / generator set, make sure the electric
source is 115 volts AC, 60Hz, and can provide a minimum of
24 amps.
To connect the heater unit to electric power at the job site:
DANGER
Servicing electrical components while the engine is run-
ning will result in death or serious injury. Always shut down
the engine before servicing electrical components.
1. Make sure the heater units are powered off, and the
engine is shut down. Close and latch the heating unit
outlet access door on the left side of the unit to prevent
inadvertent starting of the heater unit.
2. Open the heating unit control access door on the right
side of the unit.
3. Locate the electrical connection near the floor of the
heating unit control access compartment (A, Figure 21).
Unplug the connection.
NOTE: Use the connector specified (A). Do not use the
connector going directly to the heater unit power box (B).
4. Use an extension cord with a 4-prong NEMA connector
to mate with the plug from the unit. Make sure that it is
rated for the current required by the heater unit.
5. Connect the extension cord to the electric power source.
NOTE: Power will be supplied immediately to the heater
units upon connection to the power source.
6. Check electrical connections before operating the heater
units.
Note: Be sure to unlatch and open the heating unit outlet
access door on the left side of the unit prior to operating
the heater units.
NOTICE
Disconnecting electric power before the heater units can
perform the cool down cycle could cause overheating of the
combustion chamber resulting in damage to the heater unit.
Always allow the heater units to complete the cool down
cycle before disconnecting electric power to the heater units.
Figure 21
A
B
Not
for
Reproduction
