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List of Contents Air Top 2000
Air Heater
Air Top 2000 S D (Diesel)
Air Top 2000 S B (Gasoline)
Service and Repair Manual
– Improper installation or repair of Webasto heating and cooling systems can cause
fire or the leakage of deadly carbon monoxide leading to serious injury or death.
– Installation and repair of Webasto heating and cooling systems requires special
Webasto training, technical information, special tools and special equipment.
– NEVER attempt to install or repair a Webasto heat
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Air Top 2000 S List of Contents List of Contents 1. Introduction 1.1 Scope and Purpose.................................................................................................................................101 1.1.1 Use of Air Heaters.......................................................................................................................101 1.2 Meaning of Warnings, Cautions, and Notes..........................................................................................
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List of Contents Air Top 2000 S 7. Circuit Diagrams 7.1 General....................................................................................................................................................701 8. Servicing 8.1 General....................................................................................................................................................801 8.2 Work on the Air Heater...................................................................................
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Air Top 2000 S List of Figures List of Figures 501 General Failure Symptoms .............................................................................................................................501 502 Failure Symptoms during Operation ...............................................................................................................502 601 Adjustment of CO Contents ................................................................................................................
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List of Figures Air Top 2000 S IV
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Air Top 2000 S 1 Introduction 1.4 Safety Information and Regulations 1. Introduction The general safety regulations for the prevention of acci- 1.1 Scope and Purpose dents and the relevant operating safety instructions have to be observed at all times."General Safety Regulations" This repair shop manual is intended to support famil- beyond the scope of these regulations are detailed in the iarized personnel in the repair of the Air Top 2000 S. following.The specific safety regulations applica
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1 Introduction Air Top 2000 S The heater must not be installed in the passenger or Heating Air System driver compartments of busses. Should the heater never- Heating air intake openings must be arranged so that theless be installed in such a compartment, the installa- under normal operating conditions exhaust fumes of the tion box must be sealed tight against the vehicle interior. vehicle engine or air heater are not likely to be expected. There must be sufficient ventilation of the installa
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Air Top 2000 S 1 Introduction Metal lines must be used. These may not heat to more than 110 °C should there be the possibility of contact within the room interior. Protective devices against con- tact may be fitted. Should exhaust pipes be routed through rooms accom- modating persons, these pipes shall be renewed after 10 years using genuine spare parts. Combustion Air Inlet and Exhaust Outlet During installations these ports for combustion air entry and exhaust fume exit must be of such typ
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2 General Description Air Top 2000 S A malfunction of the Air Top 2000 S is indicated by an 2. General Description error code displayed on the combination or standard timer. When equipped with the standard control dial, The air heater Air Top 2000 S operates under the the operating indicator flashes. In addition a heater check evaporator principle and basically consists of: out may be performed using a personal computer (refer to operating instructions PC air heater diagnosis). - combustion
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Air Top 2000 S 2 General Description 2.2 Heat Exchanger 2.4 Control Unit / Control Circuit Board The heat exchanger dissipates the heat provided by The control unit/control circuit board is the central con- combustion to the air delivered by the combustion and trolling unit for functional sequencing and monitoring of heating air fan. the combustion operation. A temperature sensor located on the control unit is used for temperature control. All heaters may have the temperature sensor replace
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2 General Description Air Top 2000 S 2.5 Flame Sensor 2.7 Temperature Limiter The flame sensor is a low-Ohm PTC resistor changing The temperature limiter protects the air heater against its resistance dependent on its heating by the flame. excessive operating temperatures. Overheat protection The signals are routed to the control unit for processing. is activated at a temperature higher than 150 °C to inter- The flame sensor monitors the flame operating condition rupt the electrical circuit o
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Air Top 2000 S 3 Functional Description 3. Functional Description Should no proper combustion develop within 120 sec- 3.1 Functional Description Air Top 2000 S onds (for fuel-operated within 115 seconds) the combus- tion and heating air fan speed is increased to full load for 3.1.1 Control Element approx. 30 seconds (15 seconds for fuel-operated heaters) with the glow plug on and the dosing pump off The control element is used to switch the air heater on (no fuel delivery) with a subsequent a
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3 Functional Description Air Top 2000 S 3.1.4 Heating Operation 3.1.7 Switch-Off During operation the combustion exhaust gasses flow Switching the heater off extinguishes the operation indi- through the heat exchanger charging its walls with com- cation of the control element. bustion heat, which in turn is taken up by the heating air If no fuel has been delivered or if the air heater is in con- delivered by the heating air fan to be routed to the ve- trol idle, the air heater is deactivated
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Air Top 2000 S 4 Technical Data Fuel for Air Top 2000 S B (gasoline): 4. Technical Data The fuel specified by the manufacturer must be used. As long as no threshold values are given, the following Fuel for Air Top 2000 S D (diesel/PME): technical data are understood to include tolerances of The diesel fuel specified by the vehicle manufacturer ±10% usual for heaters at an ambient temperature of must be used. +20 °C and at nominal voltage and conditions. We know of no negative influences due
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5 Troubleshooting Air Top 2000 S CAUTION 5. Troubleshooting Troubleshooting is normally limited to the isolation of defective components. The following causes for trouble are not considered and 5.1 General should always be checked for to exclude them as cause for trouble: A malfunction of the Air Top 2000 S is indicated by an error code displayed on the combination or standard corrosion on connector timer. When equipped with a standard control dial loose contact on connector the operating
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Air Top 2000 S 5 Troubleshooting failure symptom listed, in emergencies, assistance by our 5.3 Failure Symptoms during Operation service technicians may be requested. The following table (Fig. 502) lists the possible failure NOTE symptoms as they might occur during the functional Overheating and dosing pump failure are always indi- sequence of operation. cated additionally after run-down by the flashing LED of the control dial. In case of malfunction the failure is to be isolated and remov
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5 Troubleshooting Air Top 2000 S 5.4 Error Code Output When equipped with a combination or standard timer a malfunction will cause an error code output to the dis- play of the timer for indication. NOTE When equipped with a control dial, the error code output is indicated by flashing of the operating indica- tor/error code indication. The number of flash pulses corresponds to the number indicated in the table below. After a quick pulse train there will always be an error code output. Error c
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Air Top 2000 S 6 Functional Tests CAUTION 6. Functional Tests Set potentiometer slowly; observe end positions. Adjustment may be performed at any electrical system 6.1 General voltage. This section describes the on-vehicle and off-vehicle Clockwise rotation increases the fan speed and de- testing of the air heater to check its proper operation. creases the CO contents. Counterclockwise rotation de- 2 creases the fan speed and increases the CO contents. 2 WARNING The air heater shall not be
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6 Functional Tests Air Top 2000 S 6.3 Components Testing CAUTION During electrical testing always ensure that the control unit and the component under test are electrically discon- nected from each other. 6.3.1 Glow Plug Resistance Test During electrical testing of the glow plug using a digital multimeter, the following readings should be obtained: Glow plug 12 Volt (red) 24 Volt (green) Resistance at 25 °C: 0.324 ... 0.360 Ω 1.3 ... 1.44 Ω Test current: < 5 mA < 5 mA 6.3.2 Flame Sensor Resis
