The fuel supply line must have a fuel filter to prevent contaminates from entering the Heater fuel system. Large
contaminates may block fuel flow, or prevent the Injector from closing properly. A Fuel Pressure Sensor on the Heater
fuel inlet will signal when the fuel pressure delivered to the Heater is below 3 PSIG. Normal operation, with full heat
output, can still be achieved even at a fuel supply pressure as low as 3 PSIG.
Ventilation air is drawn from within the vehicle at the Heater inlet by a high flow Vent Fan. The vent air stream is heated
as it flows past the Burner and the Heat Exchanger before it is discharged out of the Heater outlet.
In high heat mode the temperature of the outlet air is about 250F higher than the inlet air. For example, if the inlet air is
-40F, then the outlet air will be about 210F. In low heat mode the vent air flow remains the same, but the outlet air
temperature is about 125F higher than the inlet air.
The amount of heat produced will begin to be automatically reduced if the outlet air temperature exceeds 325F. If the
outlet air temperature exceeds 345F, the Heater will force a shut down, and enter purge mode.
The heated outlet air may be discharged into a duct that distributes the heated air throughout the vehicle. Such an air
duct should be 8" inside diameter, and be rated for 350F under continuous operation. The duct must allow unobstructed
Note: The ducting should be directed away from walls or obstructions to allow
clear re-circulation of vent air.
The exhaust temperature of the Heater always exceeds 500F in run mode and can reach temperatures as high as
1,300F. The Heater Exhaust Tube connects to a 2" inside diameter duct. The duct must be rated for at least 1,100F
continuous operation, be leak tight, and secured from movement.
Two semi-circular shells, top and bottom, are used to enclose the Heater. A seam on each side of the enclosure is used
to minimize ventilation air leakage and maximize structural strength. A Top Housing protrudes from the Top Shell of the
Heater. This Top Housing contains most of the fuel system, combustion air system and diagnostic display components.
The Top Housing can be accessed directly by removing the Top Cover.