Note
♦
If there is still too much residual heat in the heat exchanger
from a previous heating operation, only the combustion air
blower starts up at first (cold blowing).
♦
The »start« takes place once the existing residual heat has
been dissipated.
Start of auxiliary air heater
Fuel delivery starts after about 60 seconds and the fuel/air mixture
in the combustion chamber ignites. The glow plug is switched off
60 seconds after the combination sensor (flame monitor and
overheating sensor) has detected the flame.
The heater is now in control mode and reaches the “Power” gov‐
ernor state after a short duration.
Temperature selection with control element
The desired interior temperature is preselected using the control
dial. The value to be set can be chosen from a range of between
+10°C and +30°C, depending on the version of the heater unit
installed as well as the volume of the space to be heated and the
prevailing ambient temperature.
The setting to be selected on the control knob in this case is based
on experience.
Heater regulation
The room temperature or temperature of the drawn heated air is
continuously measured during heating. Regulation starts if the
temperature is higher than the temperature selected on the con‐
trol element.
There are 4 control levels provided in order that the heat flow de‐
livered by the heater can be finely adjusted to the heat demand.
The blower speed and fuel volume correspond to the particular
control level in this case.
If the set temperature is still exceeded even at the lowest control
level, then the heater unit enters control level “Off”, and the blower
continues to operate for about 4 minutes to cool down.
Then, until the restart, the combustion air blower continues to run
at minimum speed (recirculated air mode) or is switched off (fresh
air mode).
Switching off
When the heater unit is switched off, the warning lamp goes out
and the fuel delivery is switched off. The blower continues oper‐
ating for about 4 minutes to provide cooling.
For cleaning, the glow plug is switched on for 40 seconds during
the blower run-on.
Note
The heater unit is switched off without any run-on time if no fuel
was pumped before the switch-off or if the heater unit is in the
control level “OFF”.
Control and regulating units for auxiliary air heater
♦ 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
Transporter 2020 ➤
Auxiliary heater - Edition 04.2020
9. Regulation of auxiliary air heater
55
