Webasto Air Top 2000 STC, Air Top 2000 STC B, Air Top 2000 STC D Workshop Manual
Luft-Heizgeräte
Air Heaters
03/2003
Workshop Manual
Air Top 2000 STC
Trade names:
Air Top 2000 STC B (petrol)
Air Top 2000 STC D (diesel)
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.
To install and repair Webasto heating and cooling systems you need to have completed a
Webasto training course and have the appropriate technical documentation, special tools
and special equipment.
Only genuine Webasto parts may be used. See also Webasto air and water heaters
accessories catalogue.
NEVER try to install or repair Webasto heating or cooling systems if you have not completed
a Webasto training course, you do not have the necessary technical skills and you do not
have the technical documentation, tools and equipment available to ensure that you can
complete the installation and repair work properly.
ALWAYS carefully follow Webasto installation and repair instructions and heed all
WARNINGS.
Webasto rejects any liability for problems and damage caused by the system being installed
by untrained personnel.
Air Top 2000 STC Table of Contents
Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.1 Contents and purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
1.1.1 Use of air heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.2 Meaning of signal words . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.2.1 General safety information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
2 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
2.1 Drive unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .201
2.2 Heat exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
2.3 Burner with combustion chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .202
2.4 Control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .202
2.5 Flame monitor (petrol heater only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
2.6 Glow plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
2.7 Overheating sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
2.8 Fuel pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
3 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
3.1 Control element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
3.2 Switching on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .301
3.3 Heating mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .301
3.4 Control mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
3.5 Control pause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
3.6 Switching off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .302
3.7 Heater functions in ADR vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
3.8 Fault switch-off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
3.8.1 Fault monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .303
3.8.2 Resetting fault switch-off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .303
4 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401
4.1 General technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401
4.1 Setpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
5 Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
5.1 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
5.2 General fault symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .501
5.3 Fault symptoms during operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .502
5.4 Fault code output (hexadecimal / Webasto Thermo Test) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
5.5 Fault code output (flashing or FXX output). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .506
6 Function checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
6.1 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
6.2 Required test and measuring equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
6.3 Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603
6.3.1 Setting the CO2 content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .603
6.3.2 CO2 setting for reference heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603
6.4 Testing individual components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604
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Table of Contents Air Top 2000 STC
6.4.1 Component: burner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605
6.4.2 Testing resistance of flame monitor (petrol heater only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 606
6.4.3 Component: glow plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 608
6.4.4 Component: drive unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610
6.4.5 Component: overheating temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611
6.4.6 Component: control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 612
6.4.7 Component: heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613
7 Wiring diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 701
7.1 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 701
7.2 System wiring diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 702
7.3 Legends to system wiring diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 704
7.4 Pin assignments plug connection X6, 18-pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 705
8 Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.1 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.2 Working on the heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.3 Working on the vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.4 Heater test run . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.5 Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.6 Visual inspection and installation requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.6.1 Heating air system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.6.2 Fuel supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
8.6.2.1 Fuel take-off, general . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
8.6.2.2 Permissible fuel pressure fuel line lengths. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
8.6.2.3 Fuel take-off via tank drain plug (from plastic or metal fuel tank) . . . . . . . . . . . . . . 803
8.6.2.4 Webasto tank extracting device for plastic fuel tank . . . . . . . . . . . . . . . . . . . . . . . . 803
8.6.2.5 Webasto tank extracting device for metal tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803
8.6.2.6 Fuel lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803
8.6.2.7 Connecting 2 fuel lines with a hose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804
8.6.3 Fuel pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804
8.6.3.1 Installation location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804
8.6.3.2 Installation and attachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804
8.6.4 Fuel filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805
8.6.5 Combustion air supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805
8.6.6 Exhaust line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805
8.6.7 Exhaust silencer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805
8.6.8 Combustion air intake and exhaust pipes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 806
8.6.9 Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 806
8.6.9.1 Heater and control element connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 806
8.6.9.2 Supply voltage connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 806
8.6.9.3 Control element connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 807
8.7 Removing and installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 809
8.7.1 Removing and installing heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 809
8.7.1.1 Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 809
8.7.1.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 809
8.8 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 809
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Air Top 2000 STC Table of Contents
9 Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
9.1 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
9.1.1 Work on stripped down components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
9.1.1.1 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
9.1.1.2 Visual inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
9.1.2 Carrying out modifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .901
9.1.2.1 Installing of an external room temperature sensor. . . . . . . . . . . . . . . . . . . . . . . . . .901
9.2 Dismantling and assembling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
9.2.1 Removing casing parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
9.2.1.1 Cover for electrical connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .902
9.2.1.2 Grille for heating air inlet and outlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
9.2.1.3 Cover for heating air inlet and outlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .902
9.2.1.4 Upper casing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
9.2.1.5 Lower casing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
9.2.2 Fitting the casing parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
9.2.2.1 Lower casing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
9.2.2.2 Upper casing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
9.2.2.3 Cover for heating air inlet and outlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .902
9.2.2.4 Grille for heating air inlet and outlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
9.2.2.5 Cover for electrical connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .902
9.2.3 Replacing control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .904
9.2.3.1 Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904
9.2.3.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .904
9.2.4 Replacing the overheating temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904
9.2.4.1 Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904
9.2.4.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .904
9.2.5 Replacing drive unit (drive motor, combustion air fan and intake housing). . . . . . . . . . . . . . . . . . . . 904
9.2.5.1 Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904
9.2.5.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .904
9.2.6 Replacing flame monitor (petrol heater only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .905
9.2.6.1 Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905
9.2.6.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .905
9.2.7 Changing glow plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 907
9.2.7.1 Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 907
9.2.7.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .907
9.2.8 Replacing burner, combustion chamber and heat exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
9.2.8.1 Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
9.2.8.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .909
10 Packaging/storage and shipping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
10.1 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
III
Table of Illustrations Air Top 2000 STC
Table of Illustrations
Fig. 201 Air heater Air Top 2000 STC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Fig. 202 Air Top 2000 STC air heater without casing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Fig. 203 Drive unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Fig. 204 Heat exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Fig. 205 Burner with combustion chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Fig. 206 Control unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Fig. 207 Flame monitor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Fig. 208 Glow plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Fig. 209 Overheating sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Fig. 210 Fuel pump DP42 (petrol) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Fig. 211 Fuel pump DP42 (diesel) with diaphragm damper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Fig. 401 Technical Data Air Top 2000 STC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401
Fig. 402 Setpoints Air Top 2000 STC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
Fig. 501 General fault symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
Fig. 502 Fault symptoms during operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
Fig. 603 Component overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
Fig. 601 Characteristic resistance values of an overheating temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611
Fig. 701 Connector assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 701
Fig. 702 System wiring diagram Air Top 2000 STC, 12 V/24 V with rotary switch . . . . . . . . . . . . . . . . . . . . . . . . . . . 702
Fig. 703 Systems wiring diagram Air Top 2000 STC, 12 V/24 V with MultiControl. . . . . . . . . . . . . . . . . . . . . . . . . . . 702
Fig. 704 System wiring diagram Air Top 2000 STC D, 12 V/24 V ADR operation with SmartControl . . . . . . . . . . . . . 703
Fig. 705 System wiring diagram Air Top 2000 STC D, 12 V/24 V ADR operation with rotary switch . . . . . . . . . . . . . 703
Fig. 706 System wiring diagram Air Top 2000 STC, 12 V/24 V with combination timer . . . . . . . . . . . . . . . . . . . . . . . 704
Fig. 801 Fuel line lengths, inside diameter and height differences (fuel tank, heater) to fuel pump . . . . . . . . . . . . . . 802
Fig. 802 Fuel take-off via tank drain plug (plastic or metal fuel tank). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803
Fig. 803 Webasto tank extracting device (plastic fuel tank) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803
Fig. 804 Webasto tank extracting device (metal fuel tank) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803
Fig. 805 Pipe/hose connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804
Fig. 806 DP42 fuel pump (installation position, petrol) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804
Fig. 807 DP42 fuel pump, installation position, diesel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804
Fig. 808 Fuel filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805
Fig. 809 Exhaust silencer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805
Fig. 810 End of exhaust pipe, installation position. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 806
Fig. 811 Removing mounting plate on fuse holder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 806
Fig. 812 Fuse holder, installation position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 806
Fig. 813 Rotary switch control element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 807
Fig. 814 Disconnecting the connector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 807
Fig. 815 Installation example of heater in recirculated air mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 808
Fig. 901 Installing an external room temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
Fig. 902 Removing / fitting casing parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903
Fig. 903 Replacing control unit, combustion air fan and overheating temperature sensor . . . . . . . . . . . . . . . . . . . . . 906
Fig. 904 Changing glow plug, replacing flame monitor, burner and heat exchanger . . . . . . . . . . . . . . . . . . . . . . . . . 908
Fig. 905 Starting air hole in burner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 910
IV
Air Top 2000 STC 1 Introduction
1 Introduction
1.1 Contents and purpose
This workshop manual is designed to assist trained personnel
in repairing both the petrol and the diesel versions of the Air
Top 2000 STC air heaters.
1.1.1 Use of air heaters
The Webasto Air Top 2000 STC air heaters are designed:
– to heat cabins, boats, commercial vehicles, minibusses,
vans/transporters, ambulances and motor homes.
– to defrost vehicle windows.
They are not approved for heating cargo areas used to carry
dangerous goods/hazardous substances.
The heaters operate independently of the engine and are
connected directly to the fuel tank and the electrical system
of the vehicle.
They may be used for vehicles with either water or air-cooled
engines.
1.2 Meaning of signal words
Throughout this manual, the signal words CAUTION, ATTEN-
ION and NOTE have the following meanings:
T
CAUTION
This signal word is used to highlight operating instructions or
procedures which, if not followed or not followed correctly,
may result in personal injury or fatal accidents.
ATTENTION
This signal word is used to highlight operating instructions or
procedures which, if not followed or not followed correctly,
may result in damage to the equipment or its components.
NOTE
This signal word is used to draw your attention to a special
feature.
1.2.1 General safety information
The mouth of the exhaust pipe should be installed facing
ownwards, to the side or, if the exhaust pipe passes under
d
the floor of the vehicle, up to the side or rear limit of the
driver's cab or of the vehicle.
The function of important parts of the vehicle must not be
adversely affected. It must not be possible for condensation
or water to collect in the exhaust pipe. Drain holes may be
used.
The electrical cables, switchgear and control units for the
heater must be arranged in the vehicle such that their function is not impaired under normal operating conditions.
Compliance with §§ 45 and 46 StVZO (German road vehicle
registration regulation) must be ensured for the installation
of fuel lines and the installation of additional fuel tanks.
The main points of this regulation:
– Fuel lines must be designed in such a way that torsion in
the vehicle, engine movements and similar do not have a
negative effect on their durability. They must be
protected from mechanical damage.
– Parts that carry fuel must be protected from heat that
could adversely affect their function and positioned such
that dripping or evaporating fuel cannot collect or ignite
on hot parts or on electrical equipment.
The heat exchanger of the air heater can be used for a
maximum period of 10 years and must then be replaced
with a genuine spare part by the manufacturer or an
authorised workshop. A label must then be affixed to
the heater showing the date of sale and the wording
"Genuine Spare Part".
When you change the heat exchanger it is also necessary that
you replace the overheating protection element (overheating
sensor) to prevent possible malfunctions caused by using the
old overheating sensor.
The Air Top 2000 STC heaters are prepared for interior installation and and sealing directly on the driver's cab floor or
wall. Non-release connections must be used in the interior for
combustion air and exhaust pipes for Webasto accessories.
The seal between the heater mounting and the vehicle floor
must always be installed otherwise harmful exhaust gases
may get into the vehicle interior.
The heating air and combustion air intake openings must be
positioned in such a way that no water can enter them when
the vehicle is driven through water at permissible levels.
The heater must not be installed in the driver's or passenger's
compartment of busses (vehicle class M2 and M3). If the
heater is nevertheless installed in such a place, the casing
must be tightly sealed from the vehicle interior. The casing
must have sufficient external ventilation to ensure a maximum temperature of 40 °C is not exceeded in the box. Faults
may occur if the temperature exceeds this level.
Due to the risk of explosion, the heater must be switched off
at filling stations and facilities.
Due to the risk of explosion, the heater must be switched off
wherever inflammable vapours or dust can form (e.g. in the
vicinity of fuel, coal, wood dust or grain stores or similar).
Due to the risk of asphyxiation and poisoning, the heater
must not be operated in enclosed areas such as garages and
workshops without an emissions extraction system even if
you use the timer.
101
1 Introduction Air Top 2000 STC
Overheating
In the event of prolonged smoke accumulation, unusual combustion noise or smell of fuel, the heater must be shut down
by removing the fuse and must not be started again until it
has been examined by Webasto-trained personnel. Liability
claims can only be asserted for proven compliance with the
maintenance and safety information by the claimant.
Installation regulations for Webasto fuel tanks for supplying
fuel to heaters in vehicles:
• The tanks must not be installed in the passenger's
compartment or driver's cab of busses.
• The fuel filler neck must not be inside the passenger's
compartment or driver's cab in any vehicle.
• Petrol fuel tanks must not be installed directly behind the
front panelling of the vehicle. They must be separated
from the engine in such a way that in the event of an
accident the fuel cannot ignite. This does not apply to
tractor units with an open driver's seat.
Due to the potential fire risk, the fuel lines (Mecanyl hose)
must not make direct contact with the exhaust pipe and must
be thermally insulated wherever necessary.
All fuel pipes must have sealed connections, they must not be
damaged in any way and must be checked at regular intervals
(at least at the same intervals as the vehicle inspection).
Keep the heating air inlet and heating air outlet free of dirt
and foreign objects. Dirty, blocked air lines can cause the
heater to shut down due to overheating.
After the heater has shut down due to overheating, check
that the air system is clear, remove any materials that may
block the air flow and have any damage to the air lines
repaired by an authorised Webasto workshop. The heater
lock-out can then be cancelled by switching the heater off
and on again. If this action does not produce the required
success (if the heater overheats again), take it to a Webasto
authorised workshop. Never remove the grill over the air inlet
of the heater.
The air outlet jets or air vents with adjustable flaps must
always be opened by a certain extent so that the air flow
through the heater is not completely blocked. At least one air
vent must be unclosable.
If the heater is installed in a storage area you must ensure
that no flammable substances are kept in this area and that
other material does not restrict the air supply to the heater.
Air lines must be securely fixed to the heater (pipe clips) and
all other connection points (vents).
ATTENTION
The points described below must be avoided:
NOTE
If any damage or leaks are found on the fuel line, the heater
must not be used until the damage has been rectified by an
authorised Webasto workshop.
Put the heater out of action by removing the fuse.
• Do not step on the heater and do not place or throw any
heavy objects onto the heater.
• Do not place any items of clothing, fabrics or similar
materials over the heater or in front of the heating air
intake side and the heating air outlet.
• The flow of hot air from the heater must not be restricted
or blocked by highly flammable substances or materials
such as rags, cleaning wool etc.
• Flammable or explosive substances and gasses must not
be placed near or in contact with the heater, the hot air
line, the hot air flow or the exhaust pipe.
• The heater must not be cleaned with a high-pressure
cleaner.
• Do not frequently switch off the heater at the main
battery switch or battery disconnector otherwise the
heater may suffer long-term damage and malfunctions.
NOTE
Failure to follow the installation instructions and the notes
contained therein will lead to all liability being refused 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 homologation / EC type licence.
102
Carefully read the operating instructions before operating the
heater.
Air Top 2000 STC 1 Introduction
Page for notes
103
2 General description Air Top 2000 STC
2 General description
The Air Top 2000 STC air heater is based on the evaporator
principle and essentially consists of:
– Drive unit (combustion air fan, heating air fan and drive
motor)
– Heat exchanger
– Burner with combustion chamber
– Control unit
– Glow plug
– Housing parts
– Base seal
Fig. 202 Air Top 2000 STC air heater without casing
2.1 Drive unit
The drive unit consists of the drive motor, combustion air fan,
eating air fan and the intake casing.
h
The combustion air fan supplies the air required for the
combustion process through the combustion air inlet into the
combustion chamber.
The heating air fan feeds the hot air from the hot air inlet via
the heat exchanger to the hot air outlet.
Fig. 201 Air heater Air Top 2000 STC
The following control and monitoring components are
integrated in the heater:
– Control unit with room temperature sensor
– Flame monitor (petrol heater only)
– Glow plug
– Overheating sensor
All Air Top 2000 STC heaters can also be controlled using an
optional external room temperature sensor.
The fuel is supplied from the external fuel tank by a fuel
pump.
Fig. 203 Drive unit
201
Air Top 2000 STC 2 General description
Combustion
chamber
Burner
Wiring
harness
Internal
room temperature
sensor
Component plug
2.2 Heat exchanger
In the heat exchanger, the heat generated by the combustion
process is transferred to the air delivered by the heating air
fan.
Fig. 204 Heat exchanger
2.3 Burner with combustion chamber
2.4 Control unit
The control unit is the central component for ensuring
t
rouble-free operation. It monitors the components,
evaluates the sensor signals and controls heating operation.
Fig. 206 Control unit
In the burner, the fuel is distributed over the metal fibre
vaporator (mesh) in the combustion chamber. The fuel/air
e
mixture burns in the combustion chamber, thus heating the
heat exchanger.
Fig. 205 Burner with combustion chamber
2.5 Flame monitor (petrol heater only)
The flame monitor is a low-impedance PTC resistor which
hanges its resistance as a function of the heat emitted by the
c
flame.
This change in resistance is evaluated by the control unit so
that the flame status is monitored throughout the heating
operation.
Fig. 207 Flame monitor
202
2 General description Air Top 2000 STC
2.6 Glow plug
The fuel/air mixture is ignited by the glow plug when the
heater is started. The glow plug is designed as an electrical
resistor and is positioned in the burner on the side opposite
the flame.
Fig. 208 Glow plug
2.7 Overheating sensor
The overheating sensor measures the temperature in the fin
rea of the heat exchanger while the heater is operating. The
a
control unit evaluates the signal, regulates the heating air
outlet temperature and controls the overheating shut-down
function.
.
2.8 Fuel pump
The fuel pump is a combined delivery, metering and a shuto
ff system for supplying fuel to the heater. The Air Top 2000
STC heater must be operated with the fuel pump DP 42.
Fig. 210Fuel pump DP42 (petrol)
Fig. 209 Overheating sensor
Fig. 211Fuel pump DP42 (diesel) with diaphragm damper
203
Air Top 2000 STC 2 General description
Page for notes
204
3 Function description Air Top 2000 STC
3 Functional description
3.1 Control element
The control element is used to:
• Switch the heater on and off.
• Set the required room temperature (intake temperature
between approx. 5 °C and 35 °C).
• Reset the heater after a malfunction.
• Display fault codes:
– Control elements with display: the fault code is
shown on the display.
– Control elements without display: the fault code is
indicated by the indicator lamp flashing in defined
sequences.
NOTE
ADR operation:
The heater is in ADR lock-out mode after an ADR shutdown.
This mode is cancelled after switching the heater off and on
again.
3.2 Switching on
Set the control element to the required temperature.
he heater will start up if the heating air temperature is lower
T
than the set temperature.
NOTE
Only the heating air fan will start up if the room temperature
is higher than the set temperature.
The heating air fan will not start up if an external room tem-
perature sensor is connected.
The flame monitor is checked. If the flame monitor now signals "light", the system will attempt to cool the flame monitor
for 60 seconds. If the flame monitor still signals "light" the
control unit will be locked out. If there is a malfunction in any
another monitored component fault lock-out will take place
with no afterrunning period.
Automatic restart
The starting procedure will be repeated if no flame is
detected. The glow plug is switched on again (clocked). The
motor of the heating and combustion air fan is set to approx.
25% of its maximum speed.
The fuel pump starts after approx. 30 seconds (petrol) or 50
seconds (diesel) and the flame begins to form. After a further
65 seconds (petrol) or 90 seconds (diesel) the glow plug is
switched off and the presence of a flame established.
If the heater again fails to ignite properly, after a 180 second
fault afterrun phase at maximum speed the heater will be
shut down and is in fault lock-out mode.
NOTE
The heater will assume fault lock-out mode after a restart.
Briefly switch the heater off and on (for at least 2 seconds) to
reset fault lock-out.
3.3 Heating mode
Combustion gasses flow through the heat exchanger during
heater operation. The combustion heat is transferred to the
walls of the heat exchanger, absorbed by the heating air
blown in by the heating air fan and blown into the vehicle
interior.
The temperature of the heating air intake is measured by a
room temperature sensor on the intake side of the heater or
an external room temperature sensor. If the measured temperature is lower than the value set on the control element,
the heating capacity will be increased to maximum.
To extend the service life of the burner the delivery rate from
the fuel pump is reduced for 10 seconds every 10 minutes
during continuous operation.
In addition, heating mode is interrupted every 8 hours in the
same way as for a control pause.
Start
When the heater is switched on, the ON indicator lamp
comes on and the glow plug is switched on (clocked). The
motor of the heating and combustion air fan is set to approx.
50% of its maximum speed.
The fuel pump starts after approx. 40 seconds and the flame
begins to form. To improve the starting characteristics, the
fuel pump and the combustion air fan are started at different
frequencies and speeds.
After a further 95 seconds (petrol) or 110 seconds (diesel) the
glow plug is switched off and the presence of a flame established.
301
3.4 Control mode
In control mode, the speed of the heating and combustion air
an and the fuel pump delivery rate are dependent on the
f
heating capacity. The glow plug is switched off.
3.5 Control pause
The heating capacity is reduced on reaching the temperature
set on the control element. The speed of the heating and
combustion air fan and the delivery rate of the fuel pump are
reduced.
Air Top 2000 STC 3 Function description
If, at minimum heating capacity, the intake temperature set
on the control element is exceeded, the fuel pump will be
shut down and combustion stops. To allow the flame to burn
out properly, the speed of the heating and combustion air fan
drops to partial load speed after 20 seconds, returns to the
initial speed after 15 seconds and then drops to the control
pause speed after 3 minutes where it remains during the
entire control pause phase.
The control pause speed for boat heaters is 0.
The heater will restart if the temperature at the room temperature sensor drops below the set temperature.
NOTE
Changes to the settings on the control element are implemented by the control unit/heater with a time delay.
3.6 Switching off
The ON indicator lamp on the control element goes out when
he heater is switched off. If no fuel has yet been delivered or
t
if the heater is in control pause mode, the heater will be
switched off immediately with no afterrunning period.
If fuel delivery has already begun it will stop immediately
when the heater is switched off. The heater is switched off in
the same way as the transition from control mode to control
pause. The heater is then switched off automatically.
NOTE
It is possible to switch the heater back on during the afterrunning period. In this case, afterrunning is completed and the
heater is then restarted.
3.7 Heater functions in ADR vehicles
NOTE
O
nly for Air Top 2000 STC diesel heaters that are installed in
vehicles for transporting dangerous goods (ADR):
Afterunning period will remain unchanged if the heater is
switched off at the control element.
A brief afterrunning period (max. 40 seconds) is started automatically when:
• The vehicle's engine is shut down
• A pumping device is placed into operation.
The control unit is in "fault lock-out" mode after an ADR shutdown. The control element must be set to "OFF" before starting up again.
3.8 Fault switch-off
The control unit detects faults in individual heater compo-
ents and malfunctions during start-up and operation. The
n
heater shuts down and assumes fault lock-out when:
• No repeated or faulty start-up
• Room temperature sensor defective
• Overheating sensor interrupted or short-circuited
• Overheating sensor installed incorrectly
• Glow plug interrupted or short-circuited
• Drive motor overloaded or blocked or short-circuited or
interrupted
• Flame monitor interrupted or short circuited
• Fault in fuel pump electrical circuit or in overheating
protection (only during start phase)
• Undervoltage below 10.5 V/21 V for longer than 20
seconds
• Overvoltage above 16 V/32 V for longer than 6 seconds
• Control unit defective
The fuel supply shuts down in the event of overheating. The
heater continues to run (afterrunning period) as when
switched off manually. Following the afterrunning period the
control unit is in fault lock-out mode if the count of the overheating counter is greater than the value programmed in the
data set (currently 20).
• Control element with display: the overheating fault code
is shown on the display.
• Control element without display: the overheating fault
code is indicated by the operating indicator flashing in
defined sequences.
Rectify fault.
Briefly switch the heater on and off (for at least 2 seconds) to
reset fault lock-out.
302
3 Function description Air Top 2000 STC
3.8.1 Fault monitoring
Overheating, incorrect start and flame failure faults are
counted and, after the maximum number of permissible
faults have been exceeded, result in heater lock-out.
The incorrect start counter is incremented by 1 each time the
heater fails to start and decremented by 1 each time it starts
correctly, but never falls below 0. If the incorrect start counter reaches the maximum permissible value of 7, this indicates that the heater is in heater lock-out mode (HGVP).
The fault counter is incremented by 1 for each malfunction,
which does not have its own counter. The fault counter is
reset to 0 at the start of control mode. If the fault counter
reaches the maximum permissible value of 10, this indicates
that the heater is in heater lock-out mode.
The overheating counter is incremented by 1 each time the
heater overheats. If the overheating counter reaches the
maximum permissible value of 20, this indicates that the
heater is in heater lock-out mode.
The flame interruption counter (FAZ) is incremented by 1
each time the flame fails during heating mode. The counter
is decremented by 1 each time the heater assumes control
mode.
If the flame interruption counter reaches a value of 3 the
heater will assume fault lock-out mode and the permanent
flame interruption counter is incremented by 1. In control
mode, the permanent flame interruption counter is decremented by 1. When the heater is burning properly again, the
permanent flame interruption counter will return to 0 after a
few control cycles. If the permanent flame interruption counter exceeds the maximum permissible value of 3, the heater
will assume heater lock-out mode.
3.8.2 Resetting fault switch-off
1. Switch on the heater
2. There is a fault and it is detected by the control unit
as a malfunction
3. The fault code is shown on the control element
4. If set, cancel heater lock-out (as described in the fol-
lowing)
4.1. The heater detects a fault as a malfunction
4.2. Fault switch-off followed by fault lock-out
4.3. The fault code is shown on the control element
5. Switch off the heater
6. Determine cause of fault (e.g. with or without fault
code, visual inspection of fuses and plug connections,
...)
7. Rectify fault
8. Switch on the heater
9. Reset fault lock-out
10. The heater assumes control mode
Certain faults add to the fault count in the fault code mem-
ry. The heater assumes heater lock-out mode when the
o
number of faults in the fault code memory exceeds a limit
value. The maximum number of fault in the fault code memory and the limit value of the fault code memory is defined by
Webasto.
303
Reset heater lock-out
Heater lock-out can be reset:
– With Webasto Thermo Test PC diagnostics (WTT)
– or by switching on the heater.
Pull fuse F1 for at least 10 s.
Switch off the heater.
Reinsert fuse F1.
Switch on the heater.
Reset permanent heater lock-out
Only for "OE" heater variants that are integrated in bus sys-
tems.
The lock-out can only be released with the vehicle-specific
computer diagnosis system.
Air Top 2000 STC 3 Function description
Page for notes
304
4 Technical Data Air Top 2000 STC
4 Technical data
Wherever no limit values are specified, the technical data in
the table refer to the standard heater tolerances of ±10% at
an ambient temperature of +20 °C and at rated voltage
under standard conditions.
Fuel for Air Top 2000 STC B (petrol):
The fuel in accordance with DIN EN 228 as specified by the
vehicle manufacturer should be used.
Fuel for Air Top 2000 STC D (diesel/FAME):
The diesel fuel in accordance with DIN EN590 specified by the
Electrical components:
The control unit, drive motor for heating air and combustion
air fan as well as the glow plug are designed for 12 Volt or
24 Volt.
vehicle manufacturer must be used. Class EL fuel oil (not L
fuel oil) can also be used provided it complies with the normal
quality as per DIN 51603 available in the German market.
There are no known adverse effects of using additives.
The temperature sensor and flame monitor (only petrol
heater) are not designed for specific voltages.
If fuel is taken from the vehicle's fuel tank, follow the additive
instructions issued by the vehicle manufacturer.
When changing to low-temperature fuel, the heater must be
4.1 General technical data
Heater Op
Type approval EMC
Design Air heater with evaporator burner
Heat flow Control range 1.0 - 2.0 kW 0.9 - 2.0 kW
eration Air Top 2000 STC B Air Top 2000 STC D
E1 R10- 04 1085
Heater
E1 R122- 00 0216
Fuel Petrol
DIN EN 228
DIN 51625
Fuel consumption Control range 0.1 - 0.2 kg/h (0.14 - 0.27 l/h) 0.1 - 0.21 kg/h (0.12 - 0.24 l/h)
Rated voltage 12 Volt 12 / 24 Volt
Operating voltage range 10.5 - 16 Volt 10.5 - 16 / 20.5 - 31 Volt
Rated power consumption Control range 14-29 W
Permissible ambient temperature:
Heater: - Operation
- Storage
Fuel pump: - Operation
- Storage
Permissible combustion air intake temperature
Adjustment range for interior temperature
Volumetric heating air flow rate
at motor speed
CO2 in exhaust gas (permitted function
range)
-40 to + 20 °C (petrol), -40 to + 30 °C (diesel),
Control range +5 to + 35 °C
at 0.5 mbar max. 93 m3/h
1 kW
2 kW
5.0 - 8.0 %
9.0 - 12.5 %
-40 to + 40 °C
-40 to + 85 °C
-40 to + 85 °C
-40 to + 20 °C
t 4750 U/min
a
Diesel/FAME
DIN EN 590
DIN 51603
DIN EN 14214
5.0 ... 8.0 %
9.0 ... 12.5 %
Heater dimensions Length 311 ± 2 mm
Width 120 ± 1 mm
Height 121 ± 1 mm
Weight 2.6 kg
Fig. 401 Technical Data Air Top 2000 STC
401
Air Top 2000 STC 4 Technical Data
4.1 Setpoints
Heater Operation Air Top 2000 STC B and Air Top 2000 STC D
12 Volt 24 Volt
Glow plug At 25 ºC
Test current: < 5 mA
Drive motor Outside < 6 Ohm
Overheating temperature sensor at 25 ºC 2 - 2.5 Ohm
Undervoltage shut-down
(tripping time > 20 s )
Overvoltage shut-down
(tripping time > 6 s )
Flame monitor (cold test) At 25 ºC
Test current: < 5 mA
Flame monitor (hot test) At 800 – 1000 °C
Test current: < 5 mA
(ceramic rod red-hot over
approx. 20 mm length)
Red mark
0.263 - 0.323 Ohm
≤ 10.5 V ≤ 20.5 V
≥ 15 V ≥ 31 V
Green mark
1.125 - 1.375 Ohm
2.6 - 3.4 Ohm
12 - 15 Ohm
Fig. 402 Setpoints Air Top 2000 STC
402
4 Technical Data Air Top 2000 STC
Page for notes
403
Air Top 2000 STC 5 Troubleshooting
5 Troubleshooting
5.1 General information
This section describes how to identify and remedy faults in
the Air Top 2000 STC heater.
If a malfunction occurs, a fault code will be shown on the
display or the ON indicator lamp will flash (on control
elements with no display). The heater can be additionally
checked with a personal computer (see operating
instructions for Webasto Thermo Test PC Diagnostics).
ATTENTION
Troubleshooting assumes detailed knowledge of the design
and functional principle of the individual heater components
and must only be carried out by specifically trained personnel.
If in doubt, refer to Section 2 and 3 for information on how
the functions interact.
NOTE
For ADR operation only
The control unit is in "fault lock-out" mode after an ADR
shutdown or the operating voltage has been applied by
switching on the main switch in the vehicle and setting the
control element to ON. Before restarting the heater, the
control element must be set to "OFF" or the Quick Heat
button on the combination timer pressed.
ATTENTION
Troubleshooting is generally restricted to locating faulty
components. The following potential sources of malfunction
are not taken into account as they should always be checked
to rule them out as the cause of fault:
• Corroded connectors
• Loose plug connectors
• Poor crimp contacts on connectors
• Corroded cables and fuses
• Corroded battery terminals
The electrical plug connections at the control unit must be
disconnected to check individual components.
Carry out a function check in the vehicle after rectifying after
each fault.
5.2 General fault symptoms
The following table (Fig. 501) lists the possible fault symptoms.
ault symptom Possible cause Corrective measures
F
Heater cuts out automatically No combustion after start
and restart
ON indicator lamp flashes
Flame goes out during operation
ON indicator lamp flashes
Heater overheating
ON indicator lamp flashes
Battery voltage too low
ON indicator lamp flashes
Heater emits black smoke Combustion air and/or exhaust system
blocked
Briefly switch heater off and on again
Briefly switch heater off and on again
Check heating air routing for free
passage, allow heater to cool,
briefly switch heater off and on again
Charge battery
Briefly switch heater off and on again
Check combustion-air and exhaust-gas
routing for free passage
Fig. 501 General fault symptoms
501
5 Troubleshooting Air Top 2000 STC
5.3 Fault symptoms during operation
The following table (Fig. 502) lists the possible fault
symptoms during operation which should be checked first.
In the event of a malfunction, the fault is to be located and
rectified with the aid of this table. It is important to ensure
that the fault symptom is clearly identified.
Fault symptom Occurrence Possible cause
Heater will not start and LED on control
element not lit
Heater will not start, but LED lit Immediate The heater immediately assumes control pause mode
NOTE
A fault code can be shown as follows:
• MultiControl and SmartControl control element:
The malfunction is shown in the form of a fault code which begins with F and a hexadecimal combination of numbers
and/or letters (F HEX).
See “5.4 Fault code output (hexadecimal / Webasto Thermo Test)” on Page 503.
• Control elements with display (not MultiControl/SmartControl):
The malfunction is shown in the form of a fault code which begins with F and a two-number combination (FXX).
See “5.5 Fault code output (flashing or FXX output)” on Page 506.
• Control elements with indicator lamp:
the malfunction is indicated in the form of a flash code. After 5 fast flash pulses, the fault code is output by a sequence
of long flash pulses. The long flash pulses must be counted.
See “5.5 Fault code output (flashing or FXX output)” on Page 506.
Immediate Incorrect wiring, defective fuse
Fig. 502 Fault symptoms during operation
If the fault symptom is not included in this table, or if the
malfunction cannot be found under the specific fault
symptom, the fault can be determined by means of the fault
codes as described in the following tables (Section 5.4 and
5.5).
In an emergency you can contact our technicians on our
Service Hotline.
when switched on; the control pause speed for a boat
heater is 0 rpm.
502
Air Top 2000 STC 5 Troubleshooting
5.4 Fault code output (hexadecimal / Webasto Thermo Test)
Fault code
output:
HEX
00 No error No error No action necessary
01 Defective control unit
02 No start
Fault message Fault details Recommended measures
Defective control unit, wrong end-
of-line programming or coolant
temperatur sensor (at water
heaters) failure
After start-up has been repeated,
combustion still fails to occur
1) Check for fault in air intake and
2) Check for fault in fuel system
3) Check fuel pump
4) Electrical check of glow plug
Replace control unit
exhaust systems
03 Flame failure
04 Supply Voltage too high
05
06 Heating unit overheated
07 Heater lock-out Heater interlocked
Flame was detected prior to
combustion
The flame went out during
operation and combustion.
Supply voltage was too long above
maximum threshold value
Flame detector signals flame
before combustion operation
Overheat protection has been
activated or the temperature at the
heat exchanger has exceeded the
upper limit
See error 02
Check system voltage
1) Check for fault in air intake,
exhaust systems
2) Check for fault in fuel system
3) Check fuel pump
4) Electrical check of glow plug
1) Check for fault in air intake/blow-
out side, exhaust systems
2) Check for fault in fuel system
1) Reset heater lock-out and attempt
restart
2) Read out further fault messages
and work through instructions
Reset heater lock-out: switch on
heater. Pull fuse F1 for at least 10 s.
Switch off heater. Reinsert fuse F1.
Switch on the heater.
NOTE
Following fault occurred several
imes:
t
Fault counter: > 10x
False start counter: > 7x
Overheating counter: > 20x
08 Fuel pump short circuit
09
11 Wrong fuel coding
Combustion air fan short
circuit
Fuel pump has short circuit to
ground
Combustion air fan has short
circuit to ground
Incorrect parameter block or
wrong heater (diesel/gasoline)
used
Electrical check of fuel system
Electrical check of combustion air fan
motor
Replace control unit
503
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