This repair shop manual is intended to support familiarized personnel in the repair of air heaters Air Top 2000 of the fuel and Diesel type as well as of Air Top 2000 Diagnosis with serial no. 30.000 and up.
Use of Air Heaters
The air heaters Air Top 2000 and Air Top 2000 Diagnosis are used to
- heat the cabin
- defrost the windscreens.
They are not cleared for heating a transportation compartment for dangerous goods. The heaters operate independent from the vehicle engine and are connected to the fuel tank and to the electrical system of the vehicle. Their use is possible in vehicles with water- or air-cooled engines.
This workshop manual contains all information and procedures necessary for the repair of heaters Air Top 2000 and Air Top 2000 Diagnosis. The use of additional documentation is normally not necessary. Operating instructions/installation instructions and the vehicle specific installation proposal may be used as complementary information as necessary.
Webasto Air Top 2000S without Diagnosis
The control unit/control circuit board is the central controlling unit for functional sequencing and monitoring of the combustion operation. A temperature sensor located on the side is used for temperature control. 12 Volt heaters may have the temperature sensor replaced against an external temperature sensor. The combustion and heating air fan may be set by means of a potentiometer.
Webasto Air Top 2000S Diagnosis
The control unit/control circuit board is the central controlling unit for functional sequencing and monitoring of the combustion operation. A temperature sensor located on the control unit is used for temperature control. All heaters may have the temperature sensor replaced against an external temperature sensor. The combustion and heating air fan may be set by means of a potentiometer.
A malfunction in air heaters Air Top 2000 Diagnosis outputs an error code to the display of the combination or standard timer. When equipped with a control element the operating indicator flashes. In addition a heater checkout may be performed using a personal computer (refer to operating instructions PC air heater diagnosis).
Webasto Air Top 2000S Diesel Operated Heaters
With the glow plug activated the operating speed of the combustion and heating air fan is increased. After another 20 seconds the speed of the combustion and heating air fan is continuously increased within 17 seconds to full load for full heat. A flame-out during the speed rise control period causes a repeat start.
Webasto Air Top 2000S Fuel Operated Heaters
With the glow plug activated the operating speed of the combustion and heating air fan is continuously increased within 4 seconds to full load for full heat. A flame-out during the speed rise control period causes a repeat start.
Webasto Air Top 2000S Switch-off upon Failure
The control unit recognises failures of individual air heater components and malfunctions in the start sequence and in normal operation. The air heater is deactivated and enters the error lockout mode under the following conditions:
- flame sensor resistance out of tolerance
- temperature sensor resistance out of tolerance
- glow plug/glow plug trigger defective
- fan speed too low, short circuit or open circuit
- error in dosing pump electrical circuit or of overheat protection (in start phase only)
- low voltage below 10 Volt and in excess of 20 seconds for 12 Volt heaters
- low voltage below 20 Volt and in excess of 20 seconds for 24 Volt heaters
- control unit defective
- Webasto Air Top 2000S Spare Parts List.pdf
In case of overheating there will be no fuel supply. A run-down like after manual switch-off will be performed. After run-down the control unit is in the error lockout mode. Overheating is indicated by the operation indication flashing. For error unlock the air heater has to be switched off momentarily to be switched on again.