DIESEL SUPPLEMENTAL HEATER - DCHA - EXPORT
TABLE OF CONTENTS
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DIESEL SUPPLEMENTAL HEATER - DCHA -
EXPORT
DESCRIPTION........................106
OPERATION
OPERATION........................106
OPERATION - TWO ZONE ATC..........106
DIAGNOSIS AND TESTING - DIESEL
SUPPLEMENTAL HEATER - DCHA.......107
EXHAUST TUBE
REMOVAL............................107
INSTALLATION........................107
FUEL DOSING PUMP
DESCRIPTION........................108
OPERATION..........................108
REMOVAL............................108INSTALLATION........................108
FUEL LINE
STANDARD PROCEDURE - CLEANING.....109
REMOVAL............................109
INSTALLATION........................110
HEATER UNIT
REMOVAL............................111
INSTALLATION........................111
SUPPLEMENTAL DIESEL HEATER WIRING
REMOVAL............................112
INSTALLATION........................112
AIR INTAKE PIPE
REMOVAL............................112
INSTALLATION........................113
DIESEL SUPPLEMENTAL
HEATER - DCHA - EXPORT
DESCRIPTION
Vehicles equipped with the optional diesel engine
are also equipped with a supplemental heater unit.
This unit is mounted under the vehicle and operates
similar to an oil fired furnace. The heater burns
small amounts of fuel to provide additional heat to
the coolant. Coolant is routed from the engine, to the
supplemental heater, and then to the front heater
core. This provides additional heat to the passenger
compartment. The system is interfaced to the vehi-
cles on-board computer systems and DRB-III diag-
nostics.
The supplemental heater unit has a electronic con-
trol unit that monitors the heat output of the heater.
The heater operates at full load (5 kW), half load or
idle mode (no additional heat) depending on collant
temperature.
OPERATION
OPERATION
The supplemental heater unit is activated via the
temperature slide control or knob on the vehicle
HVAC control unit. If the control slide or knob is
moved to or above the upper set point the heater is
activated. The unit can operate in a full or partial
load range as well as an idle mode all dependent on
the engine coolant temperature. The heater unit willalso turn off if the HVAC temperature control is low-
ered to less than the lower set point. The heater unit
can take up to three minutes to completely shut
down when either the heater temperature is set
below the lower set point or the vehicle ignition is
shut down.
The supplemental heater only operates when the
engine is running, the mileage exceeds 8 kilometer (5
mph) and the fuel tank volume exceeds 1/8 of a tank.
The heater should start if the collant temperature is
below 40 degrees celsius (104 degrees F).
NOTE: Do not apply a strong vacuum directly on
the supplemtal heater exhaust line. Place the vac-
uum within 75 mm (3 inches) of the exhaust port.
Too strong of a vacuum can prevent the heater from
starting. The heater ECU monitors the supplemental
blower speed and combustion during its start-up.
OPERATION - TWO ZONE ATC
The Two Zone ATC control head will activate the
Supplemental Heater based on engine coolant tem-
perature and interior component settings. The unit
can operate in a full or partial load range as well as
an idle mode all dependent on the engine coolant
temperature. The unit will also turn off if the HVAC
temperature control setting is lowered to less than
the lower set point. The unit can take up to three
minutes to completely shut down when either the
heater temperature is set below the lower set point of
the vehicle ignition is shut down.
24 - 106 DIESEL SUPPLEMENTAL HEATER - DCHA - EXPORTRS
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The supplemental heater only operates when the
engine is running, the mileage exceeds 8 kilometers
(5 mph) and the fuel tank volume exceeds 1/8 of a
tank. The heater should start if the coolant temper-
ature is below 40 degrees celsius (104 degrees F).
NOTE: Do not apply a strong vacuum directly on
the supplemental heater exhaust line. Place the vac-
uum within 75 mm (3 inches) of the exhaust outlet
port. Too strong of a vacuum can prevent the heaterfrom starting. The heater ECU monitors the supple-
mental blower speed and combustion during its
start-up.
DIAGNOSIS AND TESTING - DIESEL
SUPPLEMENTAL HEATER - DCHA
The following table lists possible fault symptoms of
diesel fueled heaters.
SYMPTOM POSSIBLE CAUSES
Smell of diesel fuel Check heater system integration in vehicle's fuel system. Check fuel
lines for leakage, kinks or obstructions. If OK, Inspect the inlet muffler,
drain as necessary. Re-test the unit and re-inspect. Inspect the
exhaust tube and heater unit for the presence of external fuel. If a
volume is observed on the unit or in the exhaust tube or after draining
and testing. Remove heater unit from vehicle and repair or replace
components as required.
Heater does not achieve full load
operation.Check heater operation with DRB-III and replace components as
required.
Continuous white smoke from heater
exhaust during combustion operation.Check heater operation with DRB-III and replace components as
required. White smoke is typical in extreme weather conditions.
Heater can not be switched off. Check heater operation with DRB-III and replace components as
required.
Heater does not operate. Diagnosis cabin heater ECU using the DRB-III and the procedures
listed in Vehicle Performance under Cabin Heater Diagnosis in Group
18.
Loss of coolant (Leakage) or heater
develops smoke during combustion
operation and exhaust has an
extremely sweet smell.Inspect coolant hoses for leakage, kinks or loose hose connection.
Inspect the exhaust tube assembly for continuous flow, if OK there is
an internal heater leak and unit should be inspected and components
should be replaced as required.
Loss of fuel (dripping). Check heater system integration in vehicles fuel system. Check fuel
line connection for leakage. If OK there is an internal leak and unit
should be inspected and replaced as required.
EXHAUST TUBE
REMOVAL
WARNING: THERE IS A POTENTIAL DANGER OF
SKIN BURNS AS THE HEATER AND ITS COMPO-
NENTS MAY BE VERY HOT. MAKE SURE THE
HEATER IS ALLOWED TO COOL DOWN BEFORE
ANY SERVICE WORK ON THE CABIN HEATER SYS-
TEM IS ATTEMPTED.
(1) Elevate vehicle on a lift taking note of the
exhaust tube flexible section.
(2) Remove the exhaust clamp at the flexible pipe
and steel pipe connection (Fig. 1).
(3) Remove the clamp at the flexible pipe connec-
tion and the heater unit housing (if required).(4) Remove the three screws holding the exhaust
pipe to the body.
(5) Remove the steel exhaust pipe from the vehi-
cle.
(6) Remove the flexible exhaust pipe from the
vehicle (if required).
INSTALLATION
(1) Install the flexible exhaust pipe to the heater
unit. Tighten mounting clamp.
(2) Position the steel exhaust pipe to the flexible
exhaust and install and tighten the mounting clamp.
(3) Install the three exhaust pipe screws, adjust
pipe placement as needed and tighten the screws.
(4) Install the clamp to connect the steel exhaust
pipe to the flexible exhaust pipe and tighten clamp.
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DIESEL SUPPLEMENTAL HEATER - DCHA - EXPORT (Continued)
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