Control and safety devices of auxiliary air heater Airtronic D3
♦ The start is repeated if the heater unit does not ignite within
90 seconds after fuel delivery starts. A malfunction shut-off
occurs if the heater does not ignite after another 90 seconds.
That means that fuel delivery will be ended and blower run-on
will continue for about 4 minutes. The control unit is locked out
after the permitted number of unsuccessful start attempts has
been exceeded.
♦ If the flame goes out by itself during heating operation, a new
start is performed initially. If the heating unit does not ignite
within 90 seconds after fuel delivery restarts or if it ignites but
goes out within 15 minutes, a malfunction shut-off occurs. That
means that fuel delivery will be ended and blower run-on will
continue for about 4 minutes.
Note
♦
The malfunction shut-down can be revoked by briefly switch‐
ing off and back on again.
♦
Do not repeat the switch on/off procedure more than twice.
♦ Overheating causes the combination sensor (flame monitor/
overheating sensor) to be tripped, the fuel supply is interrupted
and a malfunction shut-down is performed. Once the cause of
overheating has been eliminated, the heater unit can be re‐
started by switching off and back on again. The control unit is
locked out after the permitted number of unsuccessful start
attempts has been exceeded.
♦ A malfunction shut-down will occur 20 seconds after the lower
or upper voltage limit has been reached.
♦ The heater unit will not start if the glow plug or the blower motor
is defective, or if there is a discontinuity in the electrical cable
to the metering pump.
♦ If the combination sensor (flame monitor/overheating sensor)
is defective or there is a discontinuity in the electrical cable,
the heater unit starts and the malfunction shut-down occurs
only during the start phase.
♦ The speed of the blower motor is continuously monitored. A
malfunction shut-down will occur after 30 seconds if the blower
motor does not start or if the speed fluctuates by more than
10%.
♦ When the heater unit is switched off, the glow plug is switched
on for 40 seconds during blower run-on (post-glow) to burn off
combustion residues.
Switching off in an emergency
If an emergency shut-off (emergency off) is required during op‐
eration, proceed as follows:
• Switch off heater unit via control element, or
• Pull out fuse, or
• Isolate heater unit from battery.
Transporter 2016 ➤
Auxiliary heater - Edition 04.2020
9. Regulation of auxiliary air heater
65
