Webasto Air Top 2000 STC Instruction 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 s stems can cause fire or the
leakage of deadl carbon monoxide leading to serious injur or death.
To install and repair Webasto heating and cooling s stems ou need to have completed a
Webasto training course and have the appropriate technical documentation, special tools
and special equipment.
Onl genuine Webasto parts ma be used. See also Webasto air and water heaters
accessories catalogue.
NEVER tr to install or repair Webasto heating or cooling s stems if ou have not completed
a Webasto training course, ou do not have the necessar technical skills and ou do not
have the technical documentation, tools and equipment available to ensure that ou can
complete the installation and repair work properl .
ALWAYS carefull follow Webasto installation and repair instructions and heed all
WARNINGS.
Webasto rejects an liabilit for problems and damage caused b the s stem being installed
b untrained personnel.

Air Top 2000 STC Ta le of Contents
I
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 safet 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 onl ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .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 Trou leshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
5.1 General information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .501
5.2 General fault s mptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .501
5.3 Fault s mptoms 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

Ta le of Contents Air Top 2000 STC
II
6.4.1 Component: burner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605
6.4.2 Testing resistance of flame monitor (petrol heater onl ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 S stem wiring diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 702
7.3 Legends to s stem 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 s stem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.6.2 Fuel suppl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 suppl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 Suppl 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

Air Top 2000 STC Ta le of Contents
III
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 Carr ing 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 onl ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .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

Ta le of Illustrations Air Top 2000 STC
IV
Ta le 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 s mptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
Fig. 502 Fault s mptoms 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 S stem wiring diagram Air Top 2000 STC, 12 V/24 V with rotar switch . . . . . . . . . . . . . . . . . . . . . . . . . . . 702
Fig. 703 S stems wiring diagram Air Top 2000 STC, 12 V/24 V with MultiControl. . . . . . . . . . . . . . . . . . . . . . . . . . . 702
Fig. 704 S stem wiring diagram Air Top 2000 STC D, 12 V/24 V ADR operation with SmartControl . . . . . . . . . . . . . 703
Fig. 705 S stem wiring diagram Air Top 2000 STC D, 12 V/24 V ADR operation with rotar switch . . . . . . . . . . . . . 703
Fig. 706 S stem 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 Rotar 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

Air Top 2000 STC 1 Introduction
101
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.
The are not approved for heating cargo areas used to carr
dangerous goods/hazardous substances.
The heaters operate independentl of the engine and are
connected directl to the fuel tank and the electrical s stem
of the vehicle.
The ma 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-
TION and NOTE have the following meanings:
CAUTION
This signal word is used to highlight operating instructions or
procedures which, if not followed or not followed correctl ,
ma result in personal injur or fatal accidents.
ATTENTION
This signal word is used to highlight operating instructions or
procedures which, if not followed or not followed correctl ,
ma result in damage to the equipment or its components.
NOTE
This signal word is used to draw our attention to a special
feature.
1.2.1 General safety information
The mouth of the exhaust pipe should be installed facing
downwards, to the side or, if the exhaust pipe passes under
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
adversel affected. It must not be possible for condensation
or water to collect in the exhaust pipe. Drain holes ma be
used.
The electrical cables, switchgear and control units for the
heater must be arranged in the vehicle such that their func-
tion 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 wa that torsion in
the vehicle, engine movements and similar do not have a
negative effect on their durabilit . The must be
protected from mechanical damage.
– Parts that carr fuel must be protected from heat that
could adversel 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 e used for a
maximum period of 10 years and must then e replaced
with a genuine spare part y the manufacturer or an
authorised workshop. A la el must then e affixed to
the heater showing the date of sale and the wording
"Genuine Spare Part".
When ou change the heat exchanger it is also necessar that
ou replace the overheating protection element (overheating
sensor) to prevent possible malfunctions caused b using the
old overheating sensor.
The Air Top 2000 STC heaters are prepared for interior instal-
lation and and sealing directl 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 alwa s be installed otherwise harmful exhaust gases
ma get into the vehicle interior.
The heating air and combustion air intake openings must be
positioned in such a wa 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 tightl sealed from the vehicle interior. The casing
must have sufficient external ventilation to ensure a maxi-
mum temperature of 40 °C is not exceeded in the box. Faults
ma 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
vicinit of fuel, coal, wood dust or grain stores or similar).
Due to the risk of asph xiation and poisoning, the heater
must not be operated in enclosed areas such as garages and
workshops without an emissions extraction s stem even if
ou use the timer.

1 Introduction Air Top 2000 STC
102
In the event of prolonged smoke accumulation, unusual com-
bustion noise or smell of fuel, the heater must be shut down
b removing the fuse and must not be started again until it
has been examined b Webasto-trained personnel. Liabilit
claims can onl be asserted for proven compliance with the
maintenance and safet information b the claimant.
Installation regulations for Webasto fuel tanks for suppl ing
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 an vehicle.
• Petrol fuel tanks must not be installed directl behind the
front panelling of the vehicle. The must be separated
from the engine in such a wa that in the event of an
accident the fuel cannot ignite. This does not appl to
tractor units with an open driver's seat.
Due to the potential fire risk, the fuel lines (Mecan l hose)
must not make direct contact with the exhaust pipe and must
be thermall insulated wherever necessar .
All fuel pipes must have sealed connections, the must not be
damaged in an wa and must be checked at regular intervals
(at least at the same intervals as the vehicle inspection).
NOTE
If an damage or leaks are found on the fuel line, the heater
must not be used until the damage has been rectified b an
authorised Webasto workshop.
Put the heater out of action b removing the fuse.
Overheating
Keep the heating air inlet and heating air outlet free of dirt
and foreign objects. Dirt , 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 s stem is clear, remove an materials that ma
block the air flow and have an damage to the air lines
repaired b an authorised Webasto workshop. The heater
lock-out can then be cancelled b 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
alwa s be opened b a certain extent so that the air flow
through the heater is not completel blocked. At least one air
vent must be unclosable.
If the heater is installed in a storage area ou must ensure
that no flammable substances are kept in this area and that
other material does not restrict the air suppl to the heater.
Air lines must be securel fixed to the heater (pipe clips) and
all other connection points (vents).
ATTENTION
The points described below must be avoided:
• Do not step on the heater and do not place or throw an
heav objects onto the heater.
• Do not place an 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 b highl 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 frequentl switch off the heater at the main
batter switch or batter disconnector otherwise the
heater ma suffer long-term damage and malfunctions.
NOTE
Failure to follow the installation instructions and the notes
contained therein will lead to all liabilit being refused b
Webasto.
The same applies if repairs are carried out incorrectl or with
the use of parts other than genuine spare parts. This will
result in the invalidation of the t pe approval for the heater
and therefore of its homologation / EC t pe licence.
Carefull read the operating instructions before operating the
heater.

Air Top 2000 STC 1 Introduction
103
Page for notes

2 General description Air Top 2000 STC
201
2 General description
The Air Top 2000 STC air heater is based on the evaporator
principle and essentiall 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. 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 onl )
– 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 b a fuel
pump.
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,
heating air fan and the intake casing.
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. 203 Drive unit

Air Top 2000 STC 2 General description
202
2.2 Heat exchanger
In the heat exchanger, the heat generated b the combustion
process is transferred to the air delivered b the heating air
fan.
Fig. 204 Heat exchanger
2.3 Burner with com ustion cham er
In the burner, the fuel is distributed over the metal fibre
evaporator (mesh) in the combustion chamber. The fuel/air
mixture burns in the combustion chamber, thus heating the
heat exchanger.
Fig. 205 Burner with combustion chamber
2.4 Control unit
The control unit is the central component for ensuring
trouble-free operation. It monitors the components,
evaluates the sensor signals and controls heating operation.
Fig. 206 Control unit
2.5 Flame monitor (petrol heater only)
The flame monitor is a low-impedance PTC resistor which
changes its resistance as a function of the heat emitted b the
flame.
This change in resistance is evaluated b the control unit so
that the flame status is monitored throughout the heating
operation.
Fig. 207 Flame monitor
Combustion
chamber
Burner
Wiring
harness
Internal
room temperature
sensor
Component plug

2 General description Air Top 2000 STC
203
2.6 Glow plug
The fuel/air mixture is ignited b 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
area of the heat exchanger while the heater is operating. The
control unit evaluates the signal, regulates the heating air
outlet temperature and controls the overheating shut-down
function.
.
Fig. 209 Overheating sensor
2.8 Fuel pump
The fuel pump is a combined deliver , metering and a shut-
off s stem for suppl ing 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. 211Fuel pump DP42 (diesel) with diaphragm damper

Air Top 2000 STC 2 General description
204
Page for notes

3 Function description Air Top 2000 STC
301
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.
• Displa fault codes:
– Control elements with displa : the fault code is
shown on the displa .
– Control elements without displa : the fault code is
indicated b 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.
The heater will start up if the heating air temperature is lower
than the set temperature.
NOTE
Onl 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 sig-
nals "light", the s stem 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 an
another monitored component fault lock-out will take place
with no afterrunning period.
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 estab-
lished.
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 properl , 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.
Briefl 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 b the heating air
blown in b the heating air fan and blown into the vehicle
interior.
The temperature of the heating air intake is measured b a
room temperature sensor on the intake side of the heater or
an external room temperature sensor. If the measured tem-
perature is lower than the value set on the control element,
the heating capacit will be increased to maximum.
To extend the service life of the burner the deliver rate from
the fuel pump is reduced for 10 seconds ever 10 minutes
during continuous operation.
In addition, heating mode is interrupted ever 8 hours in the
same wa as for a control pause.
3.4 Control mode
In control mode, the speed of the heating and combustion air
fan and the fuel pump deliver rate are dependent on the
heating capacit . The glow plug is switched off.
3.5 Control pause
The heating capacit is reduced on reaching the temperature
set on the control element. The speed of the heating and
combustion air fan and the deliver rate of the fuel pump are
reduced.

Air Top 2000 STC 3 Function description
302
If, at minimum heating capacit , 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 properl , 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 temper-
ature sensor drops below the set temperature.
NOTE
Changes to the settings on the control element are imple-
mented b the control unit/heater with a time dela .
3.6 Switching off
The ON indicator lamp on the control element goes out when
the heater is switched off. If no fuel has et been delivered or
if the heater is in control pause mode, the heater will be
switched off immediatel with no afterrunning period.
If fuel deliver has alread begun it will stop immediatel
when the heater is switched off. The heater is switched off in
the same wa as the transition from control mode to control
pause. The heater is then switched off automaticall .
NOTE
It is possible to switch the heater back on during the afterrun-
ning period. In this case, afterrunning is completed and the
heater is then restarted.
3.7 Heater functions in ADR vehicles
NOTE
Onl 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 auto-
maticall 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 shut-
down. The control element must be set to "OFF" before start-
ing up again.
3.8 Fault switch-off
The control unit detects faults in individual heater compo-
nents and malfunctions during start-up and operation. The
heater shuts down and assumes fault lock-out when:
• No repeated or fault start-up
• Room temperature sensor defective
• Overheating sensor interrupted or short-circuited
• Overheating sensor installed incorrectl
• 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 (onl 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 suppl shuts down in the event of overheating. The
heater continues to run (afterrunning period) as when
switched off manuall . Following the afterrunning period the
control unit is in fault lock-out mode if the count of the over-
heating counter is greater than the value programmed in the
data set (currentl 20).
• Control element with displa : the overheating fault code
is shown on the displa .
• Control element without displa : the overheating fault
code is indicated b the operating indicator flashing in
defined sequences.
Rectif fault.
Briefl switch the heater on and off (for at least 2 seconds) to
reset fault lock-out.

3 Function description Air Top 2000 STC
303
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 b 1 each time the
heater fails to start and decremented b 1 each time it starts
correctl , but never falls below 0. If the incorrect start coun-
ter reaches the maximum permissible value of 7, this indi-
cates that the heater is in heater lock-out mode (HGVP).
The fault counter is incremented b 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 b 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 b 1
each time the flame fails during heating mode. The counter
is decremented b 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 b 1. In control
mode, the permanent flame interruption counter is decre-
mented b 1. When the heater is burning properl again, the
permanent flame interruption counter will return to 0 after a
few control c cles. If the permanent flame interruption coun-
ter exceeds the maximum permissible value of 3, the heater
will assume heater lock-out mode.
3.8.2 Resetting fault switch-off
Certain faults add to the fault count in the fault code mem-
or . The heater assumes heater lock-out mode when the
number of faults in the fault code memor exceeds a limit
value. The maximum number of fault in the fault code mem-
or and the limit value of the fault code memor is defined b
Webasto.
Reset heater lock-out
Heater lock-out can be reset:
– With Webasto Thermo Test PC diagnostics (WTT)
– or b 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
Onl for "OE" heater variants that are integrated in bus s s-
tems.
The lock-out can onl be released with the vehicle-specific
computer diagnosis s stem.
1. Switch on the heater
2. There is a fault and it is detected b 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 b 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. Rectif fault
8. Switch on the heater
9. Reset fault lock-out
10. The heater assumes control mode

Air Top 2000 STC 3 Function description
304
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4 Technical Data Air Top 2000 STC
401
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.
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.
The temperature sensor and flame monitor (onl petrol
heater) are not designed for specific voltages.
Fuel for Air Top 2000 STC B (petrol):
The fuel in accordance with DIN EN 228 as specified b the
vehicle manufacturer should be used.
Fuel for Air Top 2000 STC D (diesel/FAME):
The diesel fuel in accordance with DIN EN590 specified b the
vehicle manufacturer must be used. Class EL fuel oil (not L
fuel oil) can also be used provided it complies with the normal
qualit as per DIN 51603 available in the German market.
There are no known adverse effects of using additives.
If fuel is taken from the vehicle's fuel tank, follow the additive
instructions issued b the vehicle manufacturer.
When changing to low-temperature fuel, the heater must be
4.1 General technical data
Heater Operation Air Top 2000 STC B Air Top 2000 STC D
T pe approval EMC
Heater
E1 R10- 04 1085
E1 R122- 00 0216
Design Air heater with evaporator burner
Heat flow Control range 1.0 - 2.0 kW 0.9 - 2.0 kW
Fuel Petrol
DIN EN 228
DIN 51625
Diesel/FAME
DIN EN 590
DIN 51603
DIN EN 14214
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
-40 to + 40 °C
-40 to + 85 °C
-40 to + 20 °C (petrol), -40 to + 30 °C (diesel),
-40 to + 85 °C
Permissible combustion air intake tem-
perature
-40 to + 20 °C
Adjustment range for interior tempera-
ture
Control range +5 to + 35 °C
Volumetric heating air flow rate
at motor speed
at 0.5 mbar max. 93 m3/h
at 4750 U/min
CO2 in exhaust gas (permitted function
range)
1 kW
2 kW
5.0 - 8.0 %
9.0 - 12.5 %
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

Air Top 2000 STC 4 Technical Data
402
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
Red mark
0.263 - 0.323 Ohm
Green mark
1.125 - 1.375 Ohm
Drive motor Outside < 6 Ohm
Overheating temperature sensor at 25 ºC 2 - 2.5 Ohm
Undervoltage shut-down
(tripping time > 20 s )
≤ 10.5 V ≤ 20.5 V
Overvoltage shut-down
(tripping time > 6 s )
≥ 15 V ≥ 31 V
Flame monitor (cold test) At 25 ºC
Test current: < 5 mA 2.6 - 3.4 Ohm
Flame monitor (hot test) At 800 – 1000 °C
Test current: < 5 mA
(ceramic rod red-hot over
approx. 20 mm length)
12 - 15 Ohm
Fig. 402 Setpoints Air Top 2000 STC

4 Technical Data Air Top 2000 STC
403
Page for notes