Liability claims:
– Failure to observe the operating instructions and the infor-
mation contained in it will result in a disclaimer of liability by
Webasto.
The same applies if repairs are carried out incorrectly or with the
use of parts other than genuine spare parts. This will result in
the invalidation of the type approval for the heater and therefore
of its general operating licence/EC type approval.
– Liability claims can only be asserted for proven compliance with
the maintenance and safety instructions by the applicant.
Operating Heater
Before switching on the heater (with the ignition on), the vehicle heating system should be set
to “warm” and the vehicle heating blower should be set to the slowest setting (lower power
consumption). Depending on the type of vehicle, the air-conditioning system can perform these
settings automatically or partly autonomously. Please ask your specialist dealer to explain the
optimum settings.
For ADR hazardous material vehicles only:
The Thermo Pro 90 HDD heater is switched on and off manually by means of a switch.
Automatic controllers are prohibited. In vehicles of the type FL, the operation of these heaters
is prohibited during loading and unloading and at the loading points. The generator signal and
auxiliary drive signal are requested for this purpose.
In vehicles of type FL, the heaters are automatically switched off and the maximum ADR after-
running time is 40 s in accordance with the legal specifications.
An ADR afterrunning period takes place if:
– the generator signal (D+) is discontinued or
– the auxiliary drive signal (e.g. pumping device) is present.
After the end of the ADR afterrunning period, the control unit is in ADR locking mode.
The heater can be restarted by switching it off and on again using the “ON/OFF” switch. This
will not work while the pumping device belonging to the vehicle is in operation. The ADR
lock will not be cancelled if the “ON/OFF” switch is activated and the operating voltage Ub is
removed and reapplied.
The disconnector (emergency off switch) may only be actuated in the event of danger since the
heater will be switched off without afterrunning period (possible overheating).
Heater operation:
If the heater is switched on with a cold engine, the heater starts up in a low load range and
then increases the power. Depending on temperature, this process can take approx. 2 minutes.
The coolant temperature is controlled automatically throughout operation. The heater can also
be switched on while travelling. The vehicle blower is only switched on when the coolant tem-
perature is at around 30°C, avoiding unnecessary energy consumption. There is thus a delay in
starting the vehicle blower, depending on the temperature. When switching off the heater, a
