5
Regulation of auxiliary/supplementa‐
ry heater
⇒ “5.1 Function description”, page 30
⇒ “5.2 Heating mode”, page 30
⇒ “5.3 Switching off auxiliary/supplementary heater”, page 31
5.1
Function description
The auxiliary heater can be started by means of the remote con‐
trol, the instant heating button or appropriate programming in the
central monitor. The supplementary heater mode is started auto‐
matically by the vehicle electronics system once all the necessary
preconditions have been met.
First, a functional check of the fresh air blower - V2- and the com‐
bined glow plug with flame monitor - Q8- is performed, and then
the glow plug with flame monitor - Q8- goes through a preheating
phase.
The subsequent starting sequence depends, amongst other
things, on the coolant temperature; therefore the time required for
the starting sequence varies. In addition, fuel is supplied at this
point, the glow plug with flame monitor - Q8- is switched off in
stages and the flame monitor is activated.
At end of start phase, heater unit burns at full load first and then
stepless standard operation ensues.
The reference resistance of the glow plug with flame monitoring
- Q8- is automatically re-determined during the starting or run-on
phase, depending on the unit. This is done to compensate for
ageing-related changes.
As a consequence of this calibrating procedure, processes that
are affected can also require more time.
After expiry of maximum operating time of 120 minutes or after
manual shutdown by means of remote control or instant heating
button , auxiliary heater is switched off.
The supplementary heater is switched off if at least one of the
defined switch-on criteria is no longer met.
After switch-off, operation of the metering pump - V54- is stopped
immediately.
The combustion air blower - V6- and the glow plug with flame
monitor - Q8- continue to operate for a limited time in order to burn
the remaining fuel in the system and to cool the burner compo‐
nents.
The run-on period of the heater can vary depending on the soft‐
ware version and load level at the time of switch-off.
5.2
Heating mode
Once the coolant temperature has reached a certain level, the
control unit switches to energy-saving mode. If the coolant tem‐
perature continues to rise, the control unit switches to regulated
waiting period. If the coolant temperature does not drop during
the regulated waiting period, however, the heater unit will perform
the usual starting procedure and run in standard mode if coolant
temperature drops below a certain level.
Transporter 2016 ➤
Auxiliary heater - Edition 04.2020
30
Rep. gr.82 - Supplementary heating
