401
Thermo E+ 120/200/320 4 Heater functions
4 Heater functions
4.1 General heater functionality
description
The heater principle is based on a high-pressure atomizer
burner and is monitored by an integrated control unit.
The burner motor powers the fan and the fuel pump. The
fuel pump is coupled to the motor using a plastic coupling.
The fan produces the required combustion air, the com-
bustion air volume is impacted by the burner motor speed.
The first CO
2
adjustment was made at Valeo.
For adaption to different applications (extension of com-
bustion air intake or exhaust line) and after any main-
tenance and repair the CO
2
content is to be readjusted in
a workshop.
The fuel pressure is generated in the fuel pump and
reduced to the required pressure using a pressure limiting
valve.
A solenoid valve releases the fuel via the atomizer nozzle
for combustion in the combustion chamber.
As an option, the fuel pump can be equipped with a nozzle
block preheater.
The nozzle block preheater heats the nozzle holder with
the atomizer nozzle at temperatures below 0°C and thus
the fuel. The fuel air mixture is ignited in the combustion
chamber via a high-voltage ignition spark.
The flame is monitored by an optical flame detector inte-
grated into the control device.
Depending on the equipment, the heater is switched on
and off using a
• digital timer
•switch
• or climate control.
During heating operation the burner is automatically swit-
ched on and off. For control a temperature sensor is
installed in the coolant outlet of the heat exchanger.
The heater is switched on, when the temperature falls
short of a lower temperature threshold (72°C), and is swit-
ched off, if the upper temperature threshold (82°C) is
reached.
A distinction between parking heating and auxiliary
heating mode does not exists.
For overheating protection of the heater the switching
thresholds are modified by the control unit, if specified
temperature gradients are exceeded (gradient evalua-
tion).
An operation indicator is available for monitoring the
operation status of the heater. The operation indicator is
also used to output error messages via flash code.
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