List of Contents

Air Top 2000

Air Heater
Air Top 2000 D (Diesel) Air Top 2000 B (Gasoline)
Service and Repair Manual
Technical changes in this issue of the manual compared with its previous issue are identified with a vertical change bar on the lefthand side of columns.
Improper installation or repair of Webasto heating and cooling systems can cause fire or the leakage of deadly carbon monoxide leading to serious injury or death. Installation and repair of Webasto heating and cooling systems requires special Webasto training, technical information, special tools and special equipment. NEVER attempt to install or repair a Webasto heating or cooling system unless you have successfully completed the factory training course and have the technical skills, technical information, tools and equipment required to properly complete the necessary procedures. 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.

1. Introduction 1.1

Scope and Purpose.... 101 1.1.1 Use of Air Heaters.... 101

1.2 1.3 1.4

Meaning of Warnings, Cautions, and Notes.... 101 Additional Documentation to be used.... 101 Safety Information and Regulations.... 101 1.4.1 General Safety Notes.... 101

1.5 1.6 2.

Legal Provisions for Installation.... 102 Corrections and Improvements.... 103
General Description 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Combustion and Heating Air Fan... 201 Heat Exchanger..... 202 Burner Insert with Combustion Tube... 202 Control Unit / Control Circuit Board.... 202 Flame Sensor..... 203 Glow Plug.... 203 Temperature Limiter..... 203 Dosing Pump.... 203
Functional Description 3.1 Functional Description Air Top 2000 without Diagnosis (Fig. 301)... 301 3.1.1 3.1.2 3.1.3 3.1.4 3.1.5 3.1.6 3.1.7 3.1.8 3.1.9 3.2 Control Element.... 301 Switch-On.... 301 Stabilization.... 301 Heating Operation.... 301 Control Operation.... 302 Control Idle..... 302 Switch-Off.... 302 Functions of the Air Heater in TRS Vehicles... 302 Switch-Off upon Failure.... 302
Functional Description Air Top 2000 Diagnosis.... 304 3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 3.2.6 3.2.7 3.2.8 3.2.9 Control Element.... 304 Switch-On.... 304 Stabilization.... 304 Heating Operation.... 305 Control Operation.... 305 Control Idle..... 305 Switch-Off.... 305 Functions of the Air Heater in TRS Vehicles... 305 Switch-Off upon Failure.... 306

Technical Data..... 401

5. Troubleshooting 5.1 5.2 5.3 5.4 6.
General.....501 General Failure Symptoms.....501 Failure Symptoms during Operation....502 Error Code Output (Air Top 2000 Diagnosis)...503
Functional Tests 6.1 6.2 General.....601 Adjustments.....601 6.2.1 6.3 Adjustment of the CO2 Contents....601
Components Testing....602 6.3.1 6.3.2 Glow Plug Resistance Test....602 Flame Sensor Resistance Test....602
Circuit Diagrams 7.1 General.....701
Servicing 8.1 8.2 8.3 8.4 8.5 8.6 General.....801 Work on the Air Heater....801 Work on the Vehicle.....801 Air Heater Test Run....801 Servicing.....801 Visual Inspections and Installation Regulations...801 8.6.1 8.6.2 8.6.3 8.6.4 8.6.5 8.6.6 8.6.7 8.6.8 8.7 Heating Air System.....801 Fuel Supply....802 Dosing Pump....804 Fuel Filter....804 Combustion Air Supply....805 Exhaust Line....805 Combustion Air Intake and Exhaust Lines....805 Electrical Connections.....806
Removal and Installation....808 8.7.1 8.7.2 8.7.3 Air Heater, Removal and Installation...808 Replacement of Control Unit...808 Replacement of Temperature Limiter...808
Installation of new Control Units....811 8.8.1 8.8.2 8.8.3 Replacement of Control Unit Air Top 2000 (12 Volt) with External Temperature Sensor....811 Replacement of Control Unit Air Top 2000 (24 Volt) not TRS...811 Replacement of Control Unit Air Top 2000 (24 Volt) TRS...812

First Operation.....812

9. Repair 9.1
General..... 901 9.1.1 9.1.2 Work on Components after Disassembly... 901 Incorporation of Modifications.... 901
Disassembly and Assembly.... 902 9.2.1 9.2.2 9.2.3 9.2.4 9.2.5 9.2.6 9.2.7 Removal of Housing Components/Covers.... 902 Replacement of Control Unit... 904 Replacement of Temperature Limiter... 904 Replacement of Combustion Air Fan... 905 Replacement of Flame Sensor.... 906 Replacement of Glow Plug.... 906 Replacement of Burner Insert, Combustion Tube, and Heat Exchanger. 909
Packaging/Storage and Shipping 10.1 General..... 1001
List of Figures List of Figures
Functional Diagram (Air Top 2000 without Diagnosis)...303 General Failure Symptoms.....501 Failure Symptoms during Operation....502 Adjustment of CO2 Contents....601 Terminal Pin Assignment, Air Top 2000 Diagnosis....701 Terminal Pin Assignment, Air Top 2000 without Diagnosis...702 Circuit Diagram Automatic Control Air Top 2000 Diagnosis, 12V/24V with Control Element..703 Circuit Diagram Automatic Control Air Top 2000 Diagnosis, 12V/24V with Combination Timer.704 Circuit Diagram Automatic Control Air Top 2000 Diagnosis, 12V/24V with Control Element and Standard Timer....705 Circuit Diagram Automatic Control Air Top 2000 Diagnosis, 24V TRS Operation with Control Element....706 Circuit Diagram Automatic Control Air Top 2000 Diagnosis, 24V TRS Operation with Combination Timer...707 Circuit Diagram Automatic Control Air Top 2000 Diagnosis, 24V TRS Operation with Combination Timer and 2 Auxiliary Drives..708 Circuit Diagram Automatic Control Air Top 2000 without Diagnosis, 12V with Control Element..709 Circuit Diagram Automatic Control Air Top 2000 without Diagnosis, 12V with Control Element and Timer....710 Circuit Diagram Automatic Control Air Top 2000 without Diagnosis, 24V with Control Element..711 Circuit Diagram Automatic Control Air Top 2000 without Diagnosis, 24V with Control Element and Timer....712 Circuit Diagram Automatic Control Air Top 2000 without Diagnosis, 24V with Control Element, TRS.....713 Circuit Diagram Automatic Control Air Top 2000 Diagnosis, 24V TRS Operation with Control Element in Vehicles without Auxiliary Drive..714 Connection Diagram, Air Top 2000 Diagnosis with Combination Timer (not TRS!)..715 Fuel Supply......802 Webasto Fuel Tank Tap....803 Fuel Tapping from Plastic Tank (tapping via fuel drain plug)...803 Fuel Tapping from Plastic Tank (tapping via fitting plate)...803 Pipe/Hose Connection....804 Dosing Pumpe, Installation Position and Attachment...804 Fuel Filter.....804 Exhaust Muffler, Direction of Flow....805 Exhaust Pipe Outlet, Installation Position...805 Removal of Fuse Holder Attachment Plate....806 Fuse Holder, Installation Position....806 Control Element.....806 Pulling the Plug.....806 Example of an Installation....807 Replacement of Control Unit and Temperature Limiter (Air Top 2000 without Diagnosis)..809 Replacement of Control Unit and Temperature Limiter (Air Top 2000 Diagnosis)..810 Removal of Housing Components/Covers....903 Replacement of Combustion Air Fan (Removal)....904 Replacement of Combustion Air Fan (Disassembly)...905 Disassembly of Heat Exchanger....907

Corrections and Improvements
Deficiencies, improvements, or proposals for correction of this workshop manual are to be mailed to: Webasto Thermosysteme GmbH Abt. Technische Dokumentation D-82131 Stockdorf Telephone: / 94 - Telefax: / 64 10

2. General Description

General Description
The air heater Air Top 2000 and Air Top 2000 Diagnosis with serial no. 30.000 and up operating to the evaporator principle basically consist of: - combustion and heating air fan - heat exchanger - burner insert with combustion tube - control unit
A malfunction in air heaters Air Top 2000 Diagnosis outputs an error code to the display of the combination or standard timer. When equipped with a control element the operating indicator flashes. In addition a heater checkout may be performed using a personal computer (refer to operating instructions PC air heater diagnosis).
Air Heater Air Top 2000 Diagnosis (covers removed)

Air Heater Air Top 2000

Combustion and Heating Air Fan
For control and monitoring a - control unit/control circuit board - flame sensor - glow plug - temperature limiter - temperature sensor are located within the unit. 12 Volt heaters (Air Top 2000 without Diagnosis) may be controlled by means of an external temperature sensor. All heaters of air Top 2000 Diagnosis may be controlled by means of an external temperature sensor. Fuel supply is provided externally by a fuel dosing pump.
The combustion and heating air fan delivers the air required for combustion from the combustion air inlet to the burner insert. By means of the fan the heating air is also delivered to the air outlet.
Air Heater Air Top 2000 without Diagnosis (covers removed)

Heat Exchanger 2.4

Control Unit / Control Circuit Board
The heat exchanger dissipates the heat provided by combustion to the air delivered by the combustion and heating air fan.
Air Top 2000 without Diagnosis The control unit/control circuit board is the central controlling unit for functional sequencing and monitoring of the combustion operation. A temperature sensor located on the side is used for temperature control. 12 Volt heaters may have the temperature sensor replaced against an external temperature sensor. The combustion and heating air fan may be set by means of a potentiometer.

A short run-down (max. 40 seconds) is automatically activated if: l the vehicle engine is turned off l a conveyor facility is put into operation The short run-down time depends on the operational condition at which TRS switch-off occurs. A 40 second run-down with maximum speed is initiated (TRS switch-off) when:

3.1.5 Control Operation

During control operation fan speed and dosing pump rate of delivery are subject to heating performance. The glow plug is deactivated.

3.1.6 Control Idle

In case the air intake temperature set with the control element is exceeded and the minimum heating performance had been achieved for longer than 5 seconds, the fuel supply is cut off to terminate combustion. The motor of the combustion and heating air fan continues operation for another 155 seconds at 2/3 of maximum speed to cool down the air heater (run-down). In control idle the combustion and heating air fan runs at minimum speed. The operation indication remains lit. After reaching the air intake temperature set with the control element a new start procedure is launched (without break-away).
air heater is still in the start phase; stabilization not yet achieved air heater is in normal run-down air heater is in control idle.
A 20 second run-down is switched on in normal combustion operation with the fuel delivery immediately halted maintaining the fan speed for 5 seconds. Then the speed is increased for 30 seconds within another 5 seconds. For all heaters after July 1995 the short run-down out of all operating conditions is a max. of 20 seconds. After a TRS switch-off the control unit is in the error lockout condition. Prior to resuming operation the control element has to be set to OFF.

3.1.7 Switch-Off

Switching the heater off extinguishes the operation indication of the control element. If no fuel has been delivered (within 20 seconds for Diesel operated heaters or within 15 seconds for fuel operated heaters after switch-on) or if the air heater is in control idle, the air heater is deactivated immediately without run-down. If fuel supply has commenced it will be immediately stopped at switch-off. The fan speed decreases within 35 seconds to 2/3 of maximum. Subsequently or if the flame sensor detects no flame the fan speed is increased to maximum for 60 seconds and run-down is initiated to last 120 seconds. Run-down is automatically halted. NOTE Re-activation of the heater during run-down is permitted. Run-down will be completed first with a subsequent restart.
3.1.9 Switch-off upon Failure
The control unit recognises failures of individual air heater components and malfunctions in the start sequence and in normal operation. The air heater is deactivated and enters the error lockout mode under the following conditions:

l l l l l l l l

3.1.8 Functions of the Air Heater in TRS Vehicles
NOTE Applicable only for Air Top 2000 D Air Heaters installed in vehicles for the transportation of dangerous goods (TRS). If the heater is deactivated using the control element, run-down will not change.
flame sensor resistance out of tolerance temperature sensor resistance out of tolerance glow plug/glow plug trigger defective fan speed too low, short circuit or open circuit error in dosing pump electrical circuit or of overheat protection (in start phase only) low voltage below 10 Volt and in excess of 20 seconds for 12 Volt heaters low voltage below 20 Volt and in excess of 20 seconds for 24 Volt heaters control unit defective
In case of overheating there will be no fuel supply. A rundown like after manual switch-off will be performed. After run-down the control unit is in the error lockout mode. Overheating is indicated by the operation indication flashing. For error unlock the air heater has to be switched off momentarily to be switched on again.

100% 90% 60% 30% 0

1,3 Hz 1,0 Hz 0,8 Hz 0,6 Hz 0

102 typical seconds

(60) (120)
Fig. 301 Functional Diagram (Air Top 2000 without Diagnosis)
Start Control Operation Rated Value reached Rated Value exceeded (e.g. due to reduced heat sumption) Run-down Control Idle Start Control Operation (increased heat consumption) Switch-off Run-down
A = Control Element B = Temperature Sensor C = Glow Plug D = Combustion and Heating Air Fan E = Dosing Pump F = Flame Sensor
Functional Description Air Top 2000 Diagnosis
Should no proper combustion develop within 120 seconds (for fuel-operated within 115 seconds) the combustion and heating air fan speed is increased to full load for approx. 30 seconds (15 seconds for fuel-operated heaters) with the glow plug on and the dosing pump off (no fuel delivery) with a subsequent automatic restart. Should the no-combustion-condition persist, after another 80 seconds (for fuel operated heaters after approx. 85 seconds) there will be a switch-off by error lockout (see 3.2.9) with a run-down of the combustion and heating air fan lasting 120 seconds at 2/3 of its max. speed. 2. Start (automatic restart) Fan speed is again reduced to approx. 30% (for fuel operated heaters to approx. 50%) and fuel is delivered. During the next 20 seconds fan speed is increased to approx. 60% (for fuel-operated heaters to approx. 75%) of full speed. As soon as a flame is detected within the next 55 seconds, combustion will be stabilized. Should there be no flame condition after a total fuel delivery period of 180 seconds, fuel delivery will be stopped and the glow plug deactivated. The combustion air fan continues full load operation for another 120 seconds (run-down) and the heater enters the error lockout condition.

+10. +45 C 70 m3/h 9.5 12.0 Length mm Width mm Height mm 2.6 kg

Weight, heater

Troubleshooting

General

This section describes troubleshooting procedures for the Air Heater Air Top 2000 and Air Top 2000 Diagnosis. A malfunction in air heaters Air Top 2000 Diagnosis outputs an error code to the display of the combination or standard timer. When equipped with a control element the operating indicator flashes. In addition a heater checkout may be performed using a personal computer (refer to operating instructions PC air heater diagnosis). CAUTION Troubleshooting requires profound knowledge about structure and theory of operation of heater components and may only be performed by skilled personnel. In cases of doubt refer to Sections 2 or 3 for functional interrelations. NOTE Only for TRS operation After a TRS switch-off or power application by vehicle main power switch operation and the control element to ON, the control unit will be in error lockout. Prior to reactivation the control element must be set to OFF or the instant heat switch on the combination or standard timer be operated.
CAUTION Troubleshooting is normally limited to the isolation of defective components. The following causes for trouble are not considered and should always be checked for to exclude them as cause for trouble: corrosion on connector loose contact on connector wrong crimping on connector corrosion on electrical wiring and fuses corrosion on battery terminals If individual components are checked, the control unit electrical connections must be disconnected. After any correction of a failure a functional test has to be performed in the vehicle.

General Failure Symptoms

The following table (Fig. 501) lists the possible failure symptoms.
Failure Symptom Air heater switches off automatically
Probable Cause No combustion after start or repeat start Flame extinguishes during operation Heater overheats Operation indication flashes
Remedy Switch off heater momentarily and switch on once again Switch off heater momentarily and switch on once again Check heat air ducting for obstructions, allow heater to cool down, switch off heater momentarily and switch on once again Charge battery Switch off heater momentarily and switch on once again Check combustion and exhaust ducting for obstructions
Vehicle electrical system voltage too low
Heater expels black fumes
Combustion air and/or exhaust ducting blocked
Fig. 501 General Failure Symptoms
Failure Symptoms during Operation
failure symptom listed, in emergencies assistance by our service technicians may be requested (Tel. 089 / 94 - 512). NOTE Overheating and dosing pump failure are always indicated additionally after run-down by the flashing LED of the control element. In all cases of trouble also a defective control unit may be the cause should all other components turn out to be serviceable. Possible Causes

The following table (Fig. 502) lists the possible failure symptoms as they might occur during the functional sequence of operation. In case of malfunction the failure is to be isolated and removed using this table. It is important to accurately identify the failure symptom. Should the failure symptom not be contained in this table or the trouble not be detected under the specific Failure Symptom shows after.s immediately
No start and no illumination of LED on control element No start but LED illuminates Very low speed with no start
Wrong cabling, defective fuse

immediately immediately

Fan or control unit defective or fan blocked Control idle operation: wrong manual control (selected temperature is below air intake temperature)or wrong integration (excessive air intake temperature) Glow plug or flame sensor short or open circuit or control unit defective Fan motor obstructed, binding Flame detection erroneous Voltage to control unit too low Cabling to dosing pump, pump itself or overheat protection defective Intermittent disconnect of connection to dosing pump or to overheat protection No flame: wrong fuel supply quantity, defective or slow fan, coked burner (in particular pilot flame outlet bore), combustion air/exhaust ducting obstructed or heat exchanger coked, dosing pump seized Overheating or voltage too low or component error (flame sensor, glow plug, overheat sensor, dosing pump, burner) or no fuel supply or obstructed combustion air/exhaust ducting Fan motor failure or seizure
Motor operates momentarily and then stops Stoppage without run-down Run-down after Run-down after Run-down after and dosing pump does not cycle Run-down after

20 120

40 to 120

Run-down after

Run-down
during combustion operation
Stoppage without run-down
during combustion operation during combustion operation
Interruption of dosing pump cycling and max. speed for 30 sec with subsequent re-start
Flame-out by gas bubbles in fuel delivery or strong wind against exhaust outlet or defective no-flame detection
Fig. 502 Failure Symptoms during Operation 502
5.4 Error Code Output (Air Top 2000 Diagnosis)

Fig. 701 shows the terminal pin assignment.

violet

yellow

X1 X2 X3 X4 X5

= = = = =
Connection, Combustion and Heating Air Fan Connection, Dosing Pump Connection, Flame Sensor Connection, Glow Plug Connection, Temperature Limiter
Fig. 701 Terminal Pin Assignment, Air Top 2000 Diagnosis 701
Fig. 702 Terminal Pin Assignment, Air Top 2000 without Diagnosis
Item A1 A2 B1 B2 B3 E F2 H1 M S1 X1-X5 X6 X7 X8 X9 X11 X12 Y1
Nomenclature Air Heater Control Unit Flame Sensor Temperature Sensor Temperature Limiter Glow Plug Fuse 24V 10A/12V 15A LED green (in item S1) Motor Control Element Connection 2-pole Connection 8-pole Connection 4-pole Connection 2-pole Connection 2-pole Connection 6-pole Connection 1-pole Dosing Pump

Remark Air Top 2000

Wire Gauges
< 7.5 m 0.75 mm2 1.0 mm2 1.5 mm2 2.5 mm2 4.0 mm2 7.5 - 15 m 1.5 mm2 1.5 mm2 2.5 mm2 4.0 mm2 6.0 mm2
Flat Fuse SAE J 1284 Operation indication Rated Value Setting Switch of item A2 of item A2 of item S of item A2 of item A2 Diagnosis (K-wire)
Wire Colours bl br ge gn gr or rt sw vi ws blue brown yellow green grey orange red black violet white
Connection X11/2 and X11/3 for TRS function only
Fig. 703 Circuit Diagram Automatic Control Air Top 2000 Diagnosis, 12V/24V with Control Element
Item A1 A2 B1 B2 B3 E F2 H7
Nomenclature Air Heater Control Unit Flame Sensor Temperature Sensor Temperature Limiter Glow Plug Fuse 24V 10A/12V 15A LED red (in item P)
H8 H9 M P1 S3 X1-X5 X6 X8 X9 X11 X12 X13 Y1
Heating symbol in display (in item P) Light (in item P) Motor Combination Timer (1531) Switch Connection 2-pole Connection 8-pole Connection 2-pole Connection 2-pole Connection 6-pole Connection 1-pole Connection 12-pole Dosing Pump
Flat Fuse SAE J 1284 Instant heat switch illumination, standy indication, operating indicator light Operating indicator light, overheat indication Symbol illumination
Instant heating remote control of item A2 of item A2 of item A2 of item A2 Diagnosis (K-wire) of item P
with plus from terminal (15/75) to connection 10: permanent operation during instant heating as long as ignition on without plus to connection 10: heating time programmable as required (10 min to 120 min), default setting 120 min.
Fig. 704 Circuit Diagram Automatic Control Air Top 2000 Diagnosis, 12V/24V with Combination Timer

Flat Fuse SAE J 1284 Operation indication Symbol illumination for pre-timed operation Control Element of item A2 of item A2 of item S
Fig. 710 Circuit Diagram Automatic Control Air Top 2000 without Diagnosis, 12V with Control Element and Timer 710
Item A1 A2 B1 B2 B3 E F1 H1 M S1 X1-X5 X6 X7 X8 X11 Y
Nomenclature Air Heater Control Unit Flame Sensor Temperature Sensor Temperature Limiter Glow Plug Fuse 10A LED green (in item S1) Motor Rated Value Setting Switch Connection 2-pole Connection 8-pole Connection 4-pole Connection 2-pole Connection 2-pole Dosing Pump
Flat Fuse SAE J 1284 Operation indication Control Element of item A2 of item A2 of item S for manufacturers installations only
Fig. 711 Circuit Diagram Automatic Control Air Top 2000 without Diagnosis, 24V with Control Element
Item A1 A2 B1 B2 B3 E F1 H1 H4 M P S1 X1-X5 X6 X7 X8 X10 X11 Y
Nomenclature Air Heater Control Unit Flame Sensor Temperature Sensor Temperature Limiter Glow Plug Fuse 10A LED green (in item S1) Light (in item P) Motor Timer 1529 Rated Value Setting Switch Connection 2-pole Connection 8-pole Connection 4-pole Connection 2-pole Connection 8-pole Connection 2-pole Dosing Pump
for manufacturers installations only
Fig. 712 Circuit Diagram Automatic Control Air Top 2000 without Diagnosis, 24V with Control Element and Timer
Item A1 A2 B1 B2 B3 E F1 H1 M S1 S2 X1-X5 X6 X7 X8 X11 Y
Nomenclature Air Heater Control Unit Flame Sensor Temperature Sensor Temperature Limiter Glow Plug Fuse 10A LED green (in item S1) Motor Rated Value Setting Switch Disconnect Switch 1 or 2-pole Connection 2-pole Connection 8-pole Connection 4-pole Connection 2-pole Connection 2-pole Dosing Pump
Flat Fuse SAE J 1284 Operation indication Control Element Emergency-off Switch; electr. or pneum. of item A2 of item A2 of item S for manufacturers installations only
Fig. 713 Circuit Diagram Automatic Control Air Top 2000 without Diagnosis, 24V with Control Element, TRS
Item A1 A2 B1 B2 B3 E F2 H1 M S1 S2 X1-X5 X6 X7 X8 X9 X11 X12 Y1
Nomenclature Air Heater Control Unit Flame Sensor Temperature Sensor Temperature Limiter Glow Plug Fuse 10A LED green (in item S1) Motor Rated Value Setting Switch Disconnect Switch 1 or 2-pole Connection 2-pole Connection 8-pole Connection 4-pole Connection 2-pole Connection 2-pole Connection 2-pole Connection 1-pole Dosing Pump
Flat Fuse SAE J 1284 Operation indication Control Element Emergency-off Switch; electr. or pneum. of item A2 of item A2 of item S1 of item A2 of item A2 Diagnosis (K-wire)
Fig. 714 Circuit Diagram Automatic Control Air Top 2000 Diagnosis, 24V TRS Operation with Control Element in Vehicles without Auxiliary Drive 714

Jumper

Terminal 15 Terminal 30

Terminal 58 Terminal 31

Fig. 715 Connection Diagram, Air Top 2000 Diagnosis with Combination Timer (not TRS!)

Servicing

For reasons of the air heaters functional reliability perform the following servicing:
This section describes the servicing procedures that may be performed with the air heater installed.

Work on the Air Heater

Prior to performing any work it is mandatory to disconnect the vehicle battery main lead. As long as the air heater is in operation or in run-down, the battery main supply must not be disconnected due to the danger of overheating resulting in a response of the overheat protection. When performing extensive repairs on the heater a complete removal is advisable.When performing repairs requiring a relocation of the installation position, the relevant installation instructions and the vehicle-specific installation proposal have to be observed.
check heating air inlet and outlet for foreign matter and contamination. (Contaminated or clogged heating air ducts may lead to overheating and thus response of the temperature limiter). Clean air heater exterior (prevent the ingress of water). Examine electrical connections for corrosion of contacts and for security. Check combustion air and exhaust ducts for damage and obstructions. Check fuel lines and fuel filter for leakage. Replace fuel filter if installed.
Visual Inspections and Installation Regulations

8.6.1 Heating Air System

CAUTION The integration of the air heater into the vehicles own air system is not permitted due to the systems high pressure. The air heater can only be operated in the ventilation mode of operation. Fitted in the air heater on the heating air intake side is a temperature sensor, which operates the heater in the relevant range of performance in conjunction with the control element dependent on the air intake temperature and position of the rated value transmitter. Heating performance is selected so that after quickly reaching the preselected indoor temperature it is maintained at this value. 12 Volt heaters (Air Top 2000 without Diagnosis) may be operated with an external temperature sensor (see 9.1.2). Air heaters Air Top 2000 Diagnosis 12 Volt and 24 Volt may also be operated with an external temperature sensor (see 9.1.2). Minimum inside diameter of the heating air duct is 55 mm. Standard diameter is 60 mm. NOTE For heating air ducting only materials may be used which are temperature-proof to at least 130 C. Maximum loss of pressure between suction and delivery side of the heating air duct 1.0 mbar (10 mm water column). When exceeding this value the temperature limiter is very likely to respond. The heating air hose is to be secured at its joints.

l1 + lm l1 1.2 m l2 8.8 m

Fig. 801 Fuel Supply

the case, the Webasto fuel tap (see Fig. 802, 803 and 804) may be used. In case of a fuel pump mounted externally to the tank the fuel tap between fuel tank and fuel pump may also only be fitted using the Webasto fuel tap (e.g. Ident No. 470 910).

Hole Pattern

Fuel Tank Tap

Gasket

Tank Fitting Plate

> 25 mm

Fig. 802 Webasto Fuel Tank Tap * Use fuel tank tap only on metal fuel tanks
Fig. 804 Fuel Tapping from Plastic Tank (tapping via fitting plate) Plastic Tank NOTE The fitting plate must be made of sheet metal! 8.6.2.2 Fuel Lines Fuel lines may only be steel, copper, or plastic lines made of unhardened, light and temperature stabilised PA 11 or PA 12 ( e.g. Mecanyl RWTL) according to DIN 73378. As in most cases a permanently rising fuel line routing cannot be ensured, the inner diameter must not exceed a certain value. Starting from an inside diameter of 4 mm, air or gas bubbles accumulate resulting in malfunctions should the lines be descending or have sags. The diameters specified in Fig. 801 ensure no disturbing formation of bubbles. A descending line routing from the dosing pump to the heater should be avoided. Fig. 803 Fuel Tapping from Plastic Tank (tapping via fuel drain plug) Loose fuel lines must be secured in order to avoid sagging. The installation must ensure protection against stone impacts and undue temperatures (exhaust line). The fuel line joints are to be secured against slipping with hose clamps.
8.6.3.1 Installation Location
Connection of 2 Pipes with Hose The proper connection of fuel lines with hoses is shown in Fig. 805. correct
It is advantageous to mount the dosing pump in a cool location. The ambient temperature must never exceed +20 C during operation. Dosing pump and fuel lines must not be installed in locations exposed to heat radiated by hot vehicle components. A heat shield is to be provided as required. 8.6.3.2 Installation and Attachment
clamp wrong bubble bubble
The dosing pump is to be attached with anti-vibration mounts. The installation location is limited according to Fig. 806 to ensure sufficient self-venting capability. Due to the danger of corrosion the plug connection between dosing pump and dosing pump cable loom may only use Webasto original parts.
Fig. 805 Pipe/Hose Connection
8.6.4 Fuel Filter 8.6.3 Dosing Pump
The dosing pump is a combined delivery, dosing, and shut-off system and is subject to certain installation criteria (see Figs. 801 and 806). If there is the probability of contaminated fuel only the Webasto filter, Order No. 487 171, may be used. Installation possibly vertical up to horizontal at the most (observe direction of flow).

8.7.2 Replacement of Control Unit
8.7.2.1 Removal NOTE During removal avoid the build-up of static charge (i.e. do not touch strip conductors). 1. 2. 3. 4. 5. 6. Withdraw cover from upper housing shell according to 9.2.1.1. Disconnect plug of cable loom from control unit. Withdraw covers for heating air inlet and outlet (5 and 3) according to 9.2.1.2. Remove upper shell according to 9.2.3.1. Disconnect plugged connections (1, Fig. 815 or Fig. 816) of terminal. Remove screws (3) and remove control unit (2). 2. 3. 4. 5. 6.
Plug Connections Control Unit Screw (2) Lock Washer (2) Temperature Limiter Arrester Groove
Fig. 815 Replacement of Control Unit and Temperature Limiter (Air Top 2000 without Diagnosis) 809

XX9 X6

Fig. 816 Replacement of Control Unit and Temperature Limiter (Air Top 2000 Diagnosis)
8.8 Installation of new Control Units
CAUTION When replacing the control unit the following must be observed:
When replacing the control unit Air Top 2000 TRS (24 Volt) with a control unit Air Top 2000 Diagnosis TRS (24 Volt) perform modifications per 8.8.3. WARNING Failure to perform modifications will result in a potential safety risk.
When replacing the control unit Air Top 2000 (12 Volt) without external temperature sensor with a new control unit Air Top 2000 Diagnosis (12 Volt) without external temperature sensor no further instructions for replacement as detailed in 8.7.2 are applicable. When replacing the control unit Air Top 2000 (12 Volt) with external temperature sensor with the control unit Air Top 2000 Diagnosis (12 Volt) with external temperature sensor the modifications per 8.8.1 must be performed.
In all cases there will be no possibility for diagnosis after replacement as the wiring harness installed in the vehicle is not provided with a diagnosis connector.
8.8.1 Replacement of Control Unit Air Top 2000 (12 Volt) with External Temperature Sensor
1. 2. Remove control unit according to 8.7.2.1. Remove leaf spring contacts 4 and 6 from connector X6. NOTE The following step is not applicable when installing a new temperature sensor. 3. Position leaf spring contacts order no. 880 39A (must be ordered) and arrest in connector X9 order no. 881 97A (must also be ordered). Polarity is irrelevant. Install new control unit according to 8.7.2.2. Connect connectors X6 and X9.

4. X9 5.

Control Unit Air Top 2000 Diagnosis
8.8.2 Replacement of Control Unit Air Top 2000 (24 Volt) not TRS
1. 2. Remove control unit according to 8.7.2.1. Remove leaf spring contacts of grey and violet wire from connector X6, contacts 4 and 6. Install new control unit according to 8.7.2.2. Connect connector X6.
NOTE If a new temperature sensor is to be used place an order for no. 883 84A (including new cover).
When replacing the control unit Air Top 2000 (24 Volt) not TRS with a control unit Air Top 2000 Diagnosis (24 Volt) not TRS the modifications per 8.8.2 must be incorporated. CAUTION Not performing the modification may result in a short circuit.

Remove temperature sensor 3. Select adequate installation location for external temperature sensor. NOTE Temperature sensor should not directly be exposed to heated air flow. For installation of the sensor in the motorcar we recommend to locate the sensor on the window spar of the windshield or in the vicinity of the air intake in the air flow for air circulation operation. For installation of the sensor in the lorry we recommend to locate the sensor on the window spar of the windshield or on the underside of the roof console.
NOTE The covers for the heating air inlet and outlet must be removed. By simultaneously exerting pressure on the catches of the upper housing shell (2, Fig. 901) in the areas Y , the shell disengages an can be lifted off. 9.2.1.4 Lower Housing Shell
By simultaneously exerting a light pull to the lower housMount external temperature sensor and route cable to ing shell (4, Fig. 901) in the areas Z , the catch is released and the shell may be separated from the motor heater. housing. Install control unit.
Cover, Electrical Connection Upper Housing Shell Cover, Heating Air Outlet Lower Housing Shell Cover, Heating Air Inlet
Fig. 901 Removal of Housing Components/Covers 903
9.2.3 Replacement of Temperature Limiter
NOTE The procedure for replacement of the temperature limiter is identical for the air heater in installed or removed condition. Replacement is to be performed in accordance with 8.7.3.
9.2.2 Replacement of Control Unit
NOTE The procedure for replacement of the control unit is identical for the air heater in installed or removed condition. Replacement is to be performed in accordance with
NOTE Air heater Air Top 2000 without Diagnosis shown. Figure is also applicable for replacement of combustion air fan or Air Top 2000 Diagnosis.
Heating Air Intake Insulation Seal
Fig. 902 Replacement of Combustion Air Fan (Removal) 904
9.2.4 Replacement of Combustion Air Fan
9.2.4.1 Removal 3. 1. 2. 3. 4. 5. 6. 7. 8. Remove air heater (see 8.7.1.1). Remove control unit (see 8.7.2.1). Remove seal (3 Fig. 902) from lower housing shell and discard. Remove air heater from lower housing shell. Remove heating air intake (1, Fig. 902) and remove insulation (2). Remove screws (1, Fig. 903). Withdraw combustion air fan (3) and remove gasket (2). Perform work on components after disassembly (see 9.1.1). 4. 5. NOTE Apply Loctite to screws (1).

6. 7. 8. 9.

Bring combustion air fan into assembly position and mount using screws (1). Torque screws (1) to 4 Nm. Place air heater with heating air intake (1, Fig. 902) and insulation (2) into lower housing shell and on side lock in position in housing. Fit new seal (3) to lower housing shell. Install control unit (see 8.7.2.2). Install air heater (see 8.7.1.2). Check CO2 setting and adjust as required (see 6.2).

Air Heater
Air Top 2000 ST B (Gasoline) Air Top 2000 ST D (Diesel)

Installation Manual

Improper installation or repair of Webasto heating and cooling systems can cause fire or the leakage of deadly carbon monoxide leading to serious injury or death. Installation and repair of Webasto heating and cooling systems requires special Webasto training, technical information, special tools and special equipment. NEVER attempt to install or repair a Webasto heating or cooling system unless you have successfully completed the factory training course and have the technical skills, technical information, tools and equipment required to properly complete the necessary procedures. 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 ST

Contents
1. Safety and General Information
1.1 1.2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8

Table of Contents

Warning Symbols in this Installation Manual. 3 General Information. 3
2. Regulations for Installation in the Vehicle
Scope. 4 Position of the Heater. 4 Fuel Supply. 4 Exhaust System. 4 Combustion Air Inlet. 4 Hot Air Inlet. 4 Hot Air Outlet. 5 Automatic Control of the Heating System. 5
3. Purpose of the Heater 4. Installation

4.1 4.2 4.3 4.4 4.5

Recommended Installation Tools. 7 Air Top 2000 ST Installation Situation. 7 Installation Location. 8 To Install the Heater. 8 Optional Mounting Plate. 9
5. Factory Plate 6. Installation Example 7. Hot Air System
External Temperature Sensor. 13 7.1.1 To Install the External Temperature Sensor. 13

8. Fuel Supply

8.1 8.2 8.3 8.4
Vehicles with a Carburetor Equipped Engine. 14 Vehicles with Fuel Injection Engines. 15 Vehicles with Diesel Engines. 15 Fuel Lines. 15 8.4.1 Connecting Two Fuel Lines with a Coupler Hose. 16 8.5 Fuel Metering Pump. 16 8.5.1 Installation Location. 16 8.5.2 Installation and Attachment. 17 8.6 Fuel Filter. 17
9. Combustion Air Supply 10. Exhaust Pipe 11. Combustion Air Inlet and Exhaust Lines 12. Electrical Connections
12.1 Heater Connection. 21 12.2 Supply Voltage Connection. 21 12.3 Control Element (Rheostat) Connection. 22

13. Circuit Diagrams

13.1 Legend for Circuit Diagrams. 23

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Webasto Product N.A., Inc.
14. Starting the Heater for the First Time
14.1 Control Element Description.25 14.2 Ventilation Mode (Optional Connection).25
15. Fault Lock-out 16. Technical Data
15.1 Error Code Output.26 16.1 Electrical Components.27 16.2 Fuel for Air Top 2000 ST B (Gasoline).27 16.3 Fuel for Air Top 2000 ST D (Diesel/Heating Oil).27
17. Version 18. Drilling Template 19. Appendices
19.1 Bio-diesel Fuel Bulletin.30
Safety and General Information
Warning Symbols in this Installation Manual
The purpose of safety symbols is to attract your attention to possible hazardous conditions. This manual uses a series of symbols and signal words which are intended to convey the level of importance of the safety messages. The progression of symbols is described below. Remember that safety messages by themselves do not eliminate danger and are not a substitute for proper accident prevention measures. Indicates an imminently hazardous situation which, if not avoided, WILL result in death or serious injury.

DANGER WARNING CAUTION

Indicates a potentially hazardous situation which, if not avoided, COULD result in death or serious injury.
Indicates a potentially hazardous situation which, if not avoided, MAY result in minor or moderate injury or property damage. It may also be used to alert against unsafe practices. These symbols are used to alert the installer to important or useful information about proper installation of the equipment.

General Information

Webasto Product North America, Inc. is pleased to provide this installation manual with the Air Top 2000 ST heating system. When used according to the guidelines stated in this manual, you can expect to provide years of trouble-free, enjoyable operation for your customer. This manual represents our latest effort to produce the best technical documentation possible. In our efforts towards continuous, ongoing product improvement, we encourage our customers to write to us with their comments or criticisms concerning this manual and the Air Top 2000 ST heating system. Please write to us at: Webasto Product North America, Inc. Technical Documentation Group 15083 North Road Fenton MI 48430 You are also invited to fill out our online questionnaire concerning our technical documentation and web site at: www.techwebasto.com If you have any immediate questions concerning this manual, the installation procedures within or the product itself, please call us at: (800) 860-7866 or send a fax to: (810) 593-6001
Regulation for Installation in the Vehicle
2. Regulation for Installation in the Vehicle
Read this installation manual in its entirety before installing this equipment.

2.1.1 2.1.2

Subject to the provisions of paragraph 2.1.2, internal combustion heaters must be installed in accordance with the requirements contained in this Annex. In the case of class trailers with heaters for liquid fuel, it is presumed that these vehicles comply with the requirements in this Annex.

2.2.1 2.2.2

Position of the Heater
Parts of the vehicle body and other components in the immediate vicinity of the heater must be protected against excessive heat and the danger of contamination by fuel or oil. The internal combustion heater must not pose a fire hazard even when overheated. This requirement is deemed to have been met if care is taken during installation to ensure an adequate distance from all parts, as well as adequate ventilation and if fire-resistant materials or heat shields are used. The model/ Serial plate or a duplicate thereof (duplicate model/ Serial plate) must be fitted in such a way that it is still clearly legible when the heater has been installed in the vehicle. When positioning the heater, all reasonable precautions must be taken to minimize the risk of personal injury or damage to items in the vehicle. A clearly visible indicator within the user's field of vision must show when the heater is switched on or off.

2.2.3 2.2.4 2.2.5

2.3.1 2.3.2 2.3.3

Fuel Supply

The fuel filler neck must not be located in the passenger compartment and must have a tightly fitting cap to prevent any fuel leaks. The type of fuel and the fuel filler neck must be clearly identified on heaters for liquid fuel, for which the fuel supply is separate from the fuel supply for the vehicle. A sign must be affixed to the fuel filler neck warning that the heater must be switched off before refuelling. An identical warning must also be included in the manufacturer's operating instructions.

Exhaust System

The exhaust outlet must be positioned in such a way that exhaust fumes cannot get into the interior of the vehicle through ventilation devices, hot-air inlets or open windows.

2.5.1 2.5.2

Combustion Air Inlet
The air for the combustion chamber of the heater must not be extracted from the passenger cabin of the vehicle. The air inlet must be positioned in such a way that it cannot be obstructed by other objects.

Hot Air Inlet

The supply of heating air must consist of either fresh air or recirculated air and must be taken from a clean area which cannot be contaminated by exhaust fumes from the engine, the internal combustion heater or any other source in the vehicle. The inlet line must be protected by a grating or other suitable means.

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2.7.1 2.7.2

Hot Air Outlet

Hot air lines within the vehicle must be positioned or protected in such a way as to exclude all risk of injury or damage caused by direct contact. The air outlet must be positioned or protected so that it cannot be obstructed by other objects.
Automatic Control of the Heating System
When the engine stops, the heating system must cut out automatically and the fuel supply must be stopped within 5 seconds. The heating system may remain in operation if a manual unit has already been activated.

IMPORTANT!

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 Webasto service parts. This will result in the invalidation of the type approval for the heater and therefore of its homologation / type licence.

Purpose of the Air Heater
3. Purpose of the Air Heater
The Webasto Air Top 2000 ST air heaters are designed to heat cabins, boats, trucks, minibuses, vans and motor homes to defrost vehicle windows The air heaters operate independently of the engine and are connected to the fuel tank and the electrical system of the vehicle. They may be used for vehicles with either water or air-cooled engines. They are not designed for heating hazardous substances.

4. Installation

Installation
The regulations governing installation on pages 4 and 5 must be adhered to. The heater must not be operated without the control unit cover (this will cause the heater to overheat).
Recommended Installation and Service Tools
Digital Multi-Meter - Should be a good quality VAO meter. 1/2 Heavy-Duty, low speed drill with good quality, sharp drill bits and a selection of hole saws. Mounting/ Drilling Templates.
Air Top 2000 ST Installation Situation
NOTE: Check the installation situation of the relevant vehicle type.

Installation Location

The heater may be fitted both in the interior or on the exterior of the vehicle. If it is installed on the exterior ensure that the heater is fitted in a position where it is protected from splashing water and spray.

22 22

130 120

> 20 120

Dimensions in millimeters

>155 121

1. 2. 3. 4. Hot air inlet Hot air outlet Combustion air inlet Exhaust gas outlet 5. 6. 7. 8.

> 20

Fuel intake Space required for hot air outlet Space required for removing the heater (service) Cable outlet (either right or left)
Figure 1. Dimensions of the Heater
The heater must be installed in such a way that no water can ingress into it if the vehicle travels through a water hazard for which that vehicle is licensed. The openings for the combustion air inlet port, the exhaust outlet port and the fuel line must be sealed if the heater is installed in the interior. The seal designed and supplied for this purpose must be used (see Figure 4). The same applies when using the optional mounting plate and closed cell foam gasket (see Figure 5).
4.4 To Install the Heater
The M6 nuts must be tightened with a torque of 6 Nm +1 Nm for installing the Air Top 2000 ST heater. The installation dimensions and space requirement for service access are shown in the installation drawing (Figure 1). The specified horizontal and axial angles must not be exceeded (Figure 2).
Figure 2. Recommended Installation Positions for Diesel Heaters
We recommend that gasoline heaters be installed with the exhaust port pointing vertically downwards.
A seal (Figure 4) must be fitted between the heater and the vehicle body. This seal must be replaced each time the heater is installed. The support area for the heater foot must be flat. A special tools can be purchased from Webasto to drill the holes and, if necessary, smooth the support area. The seal can compensate for unevenness of max. 1 mm.

WARNING

The seal or foam gasket or both must be replaced each time the heater is removed and reinstalled.

26 7.5 7.5

Figure 3. Hole Pattern

Figure 4. Seal

4.5 Optional Mounting Plate
1. Seal - Heater to vehicle floor or optional mounting plate. 2. Mounting plate - Facilitates installation on corrugated vehicle floors. 3. Closed Cell Foam Gasket - Seals area between mounting plate and vehicle floor.
The seal or foam gasket or both must be replaced each time the heater is removed and re-installed.
A mounting plate template is provided in the installation kit for locating the heater on the floor of the vehicle. All recommended hole locations and sizes are included.
Figure 5. Mounting with optional mounting plate
CAUTION the mounting bolts. Doing so will cause the mounting plate to warp and result in stress
damage to the heater and fan motor.
When using the optional mounting plate and closed cell foam gasket, do not over tighten
After installation, check that the heater casing is not in contact with any parts of the vehicle body. A failure to do this may result in the hot air fan binding internally (Figure 6).
Ensure that all moving part can move freely

Figure 6. Installation

Factory Plate

5. Factory Plate

The model/serial number plate of the heater must be positioned so that it cannot be damaged and must be clearly legible when the heater is installed (otherwise a duplicate model plate must be used). Inapplicable years must be erased from the model plate.

6. Installation Example

Installation Example
Figure 7. Installation example with heater in stalled under-bunk. (Recirculation mode)

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Hot Air System

7. Hot Air System

NOTE: The heater must not be integrated into the vehicles air system. Both recirculation and fresh air modes are possible. For fresh air mode it must be ensured that the hot air is taken from an area protected from splashing water and spray and in such a way that no water can ingress into the heater if the vehicle travels through a water hazard for which that vehicle is licensed. NOTE: For fresh air mode, an external temperature sensor must be fitted in the appropriate zone. Inside the control unit there is a temperature sensor, which operates the heater in the appropriate heat output range in conjunction with the control element depending on the intake temperatures and the position of the set point generator. The heat output is controlled such that after the selected interior temperature has been reached quickly, it is then kept at this selected value. The internal diameter of the main section of the hot air line should be 60 mm (2.36 in.) minimum. NOTE: Only materials that can permanently withstand temperatures of at least 130C (266F) may be used for the hot air line. The hot air opening is to be positioned in such a way that the air is not blown on to any parts that cannot withstand the heat.

In vehicles used to transport people, the air outlet opening is to be directed in such a way that it is at least 20 cm (8 in.) away from all body parts. Maximum pressure drop between the inlet and outlet side of the hot air line: Air Top 2000 ST 1.5 hPa 1 hPa corresponds to 1 mbar corresponds to 10 mm Water Column (0.4 inches Water Column). The heaters check the internal temperature rise automatically each time they are switched on. If this is above the specified limits, the start is cancelled and error messages F10 is displayed. To ensure that the heater functions stably, the flow resistance of the connected hot air system must be reduced. The hot air hose must be secured at its connection points. If the heater is used in recirculation mode, for example, in the under bunk compartment of a trucks sleeper, without a hot air directional outlet grille, do not short circuit the hot air flow.
Figure 8. Hot air inlet and hot air outlet (recirculation mode) IMPORTANT!
If you use the heater without a hot air inlet hose, the inlet grille supplied with the heater must be used at all times. Webasto Product N.A., Inc. 12 www.techwebasto.com
NOTE: The installation must be checked for: Air short circuit between the vehicles heating system and the heater air inlet. Air short circuit between the heaters air inlet and the heaters air outlet (Figure 8).
Figure 9. Hot air inlet with inlet grille
If you use an installation box the air vent must be sealed in such a way that no hot air can get into the installation box.
External Temperature Sensor
The installation of an external temperature sensor is recommended if the heater is operated in fresh air mode. 7.1.1 To Install the External Temperature Sensor
The external temperature sensor must be installed at medium height in the passenger cabin on vertical surfaces if possible in the area that requires heating. The temperature sensor must not be in the direct current of hot air (from the vehicles own heating system or the hot air heater). by close to heat sources (for example the vehicles own heating system). be placed in direct sunlight (for example on the dashboard). be installed behind curtains or the like.
Plug X8 for external temperature sensor
External temperature sensor Terminating resistor
Figure 10. External temperature sensor - optional
The fuel is taken from the vehicle fuel tank or from a separate fuel tank. The values for the maximum pressure at the fuel extraction point are shown in Figure 11.
Permissible fuel inflow height H 0.00 m (0.00 in.) 1.00 m (39.4 in.) 2.00 m (78.7 in.) Maximum fuel intake height S At max. pressure in fuel line 0.2 bar (2.9 PSI) 0.11 bar (1.6 PSI) 0.03 bar (0.44 PSI) At max. negative pressure in the fuel tank -0.10 bar (-1.45 PSI) -0.06 bar (-0.87 PSI) -0.02 bar (-0.29 PSI)

max. 3m (9.8 ft.) I2

i2mm i2mm
0.00 m (0.00 in.) 0.50 m (19.7 in.) 1.00 m (39.4 in.)
A sign must be affixed to the fuel tanks filler neck warning that the heater must be switched off before refuelling.
I 1 + I m (32.8 ft.) I 1 1.2 m (3.9 ft.) I 2 8.8 m (28.8 ft.)

Figure 11. Fuel supply

Vehicles with a Carburetor Equipped Engine
The fuel may only be extracted using the special Webasto fuel extractor (see Figure 12) as close to the tank as possible. The connection may be made in either the supply or return line, in which case the return line must lead almost to the base of the tank (see Figure 13). The fuel extractor must be fitted in such a way that any air or gas bubbles are automatically discharged towards the tank (see Figure 12).

From Tank

a= 12 0-60

To Engine

To Fuel Metering Pump
Figure 12. Webasto fuel extractor
The fuel extractor should not be located near the engine, as gas bubbles may form in the lines on account of heat radiated from the engine. This may cause problems during combustion. Webasto Product N.A., Inc. 14 www.techwebasto.com
8.2 Vehicles with Fuel Injection Engines
When installing the heater in a vehicle with fuel injection system, it is important to establish whether the fuel pump is located inside or outside the tank. If the fuel pump is located inside the tank, fuel can only be extracted from the return line using the Webasto fuel extractor (see Figure 12), in which case it must be ensured that the return line continues almost to the bottom of the tank (see Figure 13 for details of the minimum distance from the bottom of the tank). If this is not the case Webasto fuel extractors or standpipes (see Figures 13, 14 and 15) may be used. If the fuel pump is installed outside the tank, the fuel connection may also be made between the tank and the fuel pump, again using only the Webasto fuel extractor (see Figure 12).
Vehicles with Diesel Engines
The fuel must be taken from the vehicle fuel tank or from a separate tank (see Figs. 13, 14 and 15). This separate fuel pickup precludes any effect of pressure.

25 mm (1 in.)

Figure 13. Webasto fuel standpipe
NOTE: The tank fitting must be made from metal!

Fuel Lines

Only steel, copper and plastic lines of plasticized, light and temperature-stabilized PA 11 or PA 12 (e.g. Mecanyl RWTL) pursuant to DIN 73378 may be used for the fuel lines. Since the lines normally cannot be routed with a constant rising gradient, the internal diameter must not be allowed to exceed a certain size. Air or gas bubbles will accumulate in lines with an internal diameter of more than 4 mm (5/32 in.) and these will cause malfunctions whilst the heater is operating if the lines sag or are routed downwards. The diameters specified in Figure 11 will ensure that bubbles do not form. The lines should not be routed downwards from the metering pump to the heater. Unsupported fuel lines must be secured to prevent them from sagging. They must be installed in such a way that they cannot be damaged by flying road debris and high temperatures (exhaust line). The fuel lines must be secure at the connections using hose clips to prevent their slipping.

> 25 mm (> 1 in.)

Tank Connector Plastic tank

Sealing ring

Tank Fitting Sealing ring
Figure 14. Fuel supply from plastic tank drain screw
Figure 15. Fuel supply from plastic tank fitting
Connecting Two Fuel Lines with a Coupler Hose
The correct procedure for connecting fuel lines with hosing is shown in Figure 16. Ensure that there are no leaks.

Correct Clamp

Wrong Bubble Bubble
Figure 16. Fuel line / coupler hose connection

Fuel Metering Pump

The fuel metering pump is a combined delivery, metering and shut-off system and is subject to certain installation criteria (see Figures 11 and 17). 8.5.1 Installation Location
12 V and 24 V Diesel DP 30 (with damper)
It is advisable to install the metering pump in a cool place. The maximum ambient temperature must not exceed +20 C (68 F) for gasoline heaters at any time during operation. The metering pump and fuel lines must not be installed within range of the radiated heat from hot vehicle parts. A heat shield must be used if necessary. Webasto Product N.A., Inc.

0-90 0

Install in horizontal position only!
Figure 17. Fuel metering pump DP 30.2 / 30.3
8.5.2 Installation and Attachment
The metering pump must be secured with a vibration-damping mounting. Its installation position is limited as shown in Figure 17 in order to ensure effective automatic bleeding. As a result of the risk of corrosion, only genuine Webasto parts may be used for the plug connections between the metering pump and the metering pump wiring harness.

Fuel Filter

Only a Webasto filter is allowed to be used if the fuel is expected to be contaminated. Install vertically if possible, however at least horizontally (check flow direction).
Do not substitute the Webasto supplied fuel filter with a non Webasto replacement. Irregular heater operation may result.

0 - 90

Figure 18. Fuel filter

Combustion Air Supply

9. Combustion Air Supply
Under no circumstances may the combustion air be taken from areas occupied by people. The combustion air intake opening must not point in the direction of travel. It must be located so that it cannot become clogged with dirt and road debris. NOTE: An intake silencer must be fitted if the intake hose length is greater than 0.6 m (24 in.). NOTE: The combustion air must be extracted using a combustion air line from a position that is as cool as possible and protected from splashing water. Do not use an exhaust line as the combustion air line since otherwise the metering pump cable from the combustion air inlet port may be damaged. The combustion air opening must not be under the minimum water drive-through level permitted for the vehicle. See the regulations for the installation for further regulations.

10. Exhaust Pipe

Exhaust Pipe
Rigid pipes of unalloyed or alloyed steel with a minimum wall thickness of 1.0 mm (3/64 in.) or flexible piping of alloyed steel only must be used as exhaust line. The exhaust pipe is secured to the heater using a clamping collar, for example. See the regulations for installation for other requirements. The exhaust muffler should ideally be installed near the heater. The heater may also be operated without a muffler.
Figure 19. Exhaust muffler - exhaust flow is non-directional (arbitrary)
Combustion Air Inlet and Exhaust Lines
11. Combustion Air Inlet and Exhaust Lines
Both lines are to be installed falling away from the heater. If this is not possible, a condensate drain hole with a diameter of 4 mm (5/32 in.) must be made at its lowest point.
Figure 20. Prevent the formation of condensate
The lines must not point to the front of the vehicle.
Figure 21. Lines must not point in the direction of travel
The lines must be located so that they cannot become clogged with dirt and road debris.
Figure 22. Avoid the lines becoming clogged with dirt
Length of the combustion air inlet and exhaust lines in total: With muffler: max. 2.0 m Without muffler: max. 5.0 m NOTE: If the exhaust line is over 2 m in length the lines must be insulated (to prevent falling below the dewpoint) Internal diameter of the lines: Combustion air line: exhaust line (metal): Minimum bending radius: Total bends: Combustion air line: Exhaust line:
The exhaust pipe must be securely attached no further than 150 mm (6 in.) from the end of the exhaust pipe to ensure that the angle of is maintained.

Installation position

22 mm 22 mm

max. 270 max. 270.

Discharge direction almost vertical 90 10
Figure 23. Exhaust pipe opening IMPORTANT!
If the exhaust pipe ends other than as shown in Figure 23, it will pose a fire risk. Webasto Product N.A., Inc. 20 www.techwebasto.com
12. Electrical Connections

Electrical Connections

All the cables and wires that are not required must be insulated against accidental shorting or grounding. NOTE: The electrical connection is made as shown in the system circuit diagram (Figure 31).

12.1 Heater Connection

To connect the wiring harness, remove the control unit cover on the heater and connect the wiring harness plug to the control unit.
Figure 24. To remove the control unit cover
NOTE: Raise the control unit cover on both sides using a blunt blade (Figure 24 arrows). Before using the heater for the first time, fit the control unit cover in place on the heater to prevent the escape of hot air (heater overheating). The cable passage of the cover can be placed at either the left or right side. To ensure that the cable passage in the control unit cover seals perfectly, the cable grommet is to be adjusted appropriately on the wiring harness.

Figure 32. Control element
Changes to the settings on the control element are implemented after a delay.
14.2 Ventilation Mode (Optional Connection)
Where desired, a separate switch installed between the 20 ga pink wire (X6, Pin-16) and a ground point allows the user to chose between heating and ventilation mode. Refer to Figure 31, item S3 for connection detail. In ventilation mode (switch S3 On) the fan speed is regulated by the control element knob.

Fault Lock-out

15. Fault Lock-out
The control unit continuously monitors the heater operation. The control unit identifies errors on individual heater components and faults during operation. Should the control unit experience component errors and operational faults, the heater will be shut down. The heater is shut down (fault lock-out) if: No or incorrect start Temperature sensor defective Overheating sensor interrupt or short circuit Overheating sensor installed incorrectly Ceramic glow pin interrupt or short circuit Fan motor overload or blocked or short circuit or interrupt Error in the fuel metering pump or overheating guard circuit (start phase only) Under voltage less than 10,5 V or over voltage greater than 16 V and for longer than 20 seconds (on 12 V heater) Under voltage less than 21 V or over voltage greater than 32 V and for longer than 20 seconds (on 24 V heater) Control unit defective Overheating Flame monitor defective (Gasoline heater) The fuel supply is stopped if the heater overheats. The heater continues to run in the same way as if it is switched off manually. After the heater stops the control unit will be set to fault lock-out. Overheating is indicated by the indicator flashing 10 times. Rectify the cause of the fault. To reset the fault, switch the heater on and off briefly (at least 2 seconds). If serious faults, such as overheating or no start, occur frequently, the heater will be set to fault lock-out (F 12) and can be restarted by disconnecting the supply voltage (e.g. removing the fuse).

15.1 Error Code Output

NOTE: An error code is generated on the control element indicator light after an error has occurred. When determining the generated code, there will be a series of 5 fast flashes after which, the error code will be generated by a sequence of long flash pulses, count only the long flash pulses to obtain the code. Error codes are shown in the table below. If the heater is fitted with a combination timer, an error message will appear on the display of the timer after a fault occurs. If the control element is used, the error number is indicated by the indicator light flashing: F 00 F 01 F 02 F 03 F 04 F 05 F 06 F 07 F 08 F 09 F 10 F 11 F 12 F 14 F 15 Control unit error / incorrect data set / customer bus defective No start (after 2 attempts to start) / no flame formation Flame failure (repeated more than 3 times) Under voltage or over voltage Premature flame recognition Flame monitor (gasoline heater) interrupt or short circuit Temperature sensor interrupt or short circuit Metering pump interrupt or pump short circuit Fan motor interrupt or short circuit or overload or blocked Ceramic glow pin interrupt or short circuit Overheating: Resulting in permanent heater fault lock-out Overheating sensor interrupt or short circuit Heater lock-out Overheating sensor incorrect position Set point generator interrupt 26 www.techwebasto.com

16. Technical Data

Technical Data
Except where limit values are specified, the technical data refer to the usual heater tolerances of 10% at an ambient temperature of +20 C (68 F) and at the rated voltage and in rated conditions.
16.1 Electrical Components:
Control unit, motor, metering pump, lamp in the timer and ceramic glow pin / flame monitor are designed for either 12 V or 24 V. The timer, overheating sensor and temperature sensor component are not dependent on voltage.
16.2 Fuel for Air Top 2000 ST B (Gasoline):
The fuel specified by the vehicle manufacturer must be used.
16.3 Fuel for Air Top 2000 ST D (Diesel/Heating Oil):
The diesel fuel specified by the vehicle manufacturer must be used. Heating oil may also be used as long as it complies to the normal quality available on the North American market. We know of no negative influences due to additives. If fuel is extracted from the vehicles tank, follow the additive instructions issued by the vehicle manufacturer. If you change to low-temperature fuel, the heater must be operated for approx. 15 minutes so that the fuel system is filled with the new fuel. The Air Top 2000 ST heater is also licensed for use with PME (bio-diesel), which complies with DIN EN 14214.

Heater

Type test permit Model Heat output Fuel Fuel consumption Rated voltage Operating voltage range Rated power consumption Max. ambient temperature: Heater: Metering pump Control element - Operation - Storage - Operation - Storage - Operation - Storage

Operation

EMC Heater Control range Control range

Air Top 2000 ST B

Air Top 2000 ST D
e1*72/245*95/54*1085*00 e1*2001/56*0022*00 Air heater with evaporator burner 1.0 - 2.0 kW (3753 - 7000 Btu) Gasoline 0.1. 0.2 kg/h (0.14. 0.27 l/h) 12 V 10.5 - 16 V 0.9 - 2.0 kW (3070 - 7000 Btu) Diesel/PME 0.1. 0.21 kg/h (0.12. 0.24 l/h) 12 / 24 V 10.5 - 16 /21 - 32 Volt 14 - 29 W -40. +40 C (-40. +104 F) -40. +85 C (-40. +185 F) -40. +20 C (-40. +68 F) -40. +85 C (-40. +185 F) -40. +75 C (-40. +167 F) -40. +85 C (-40. +1854 F) -40. +20 C (-40. +68 F)

Control range

Maximum combustion air inlet temperature Adjustment range for interior temperature Delivery rate for hot air at fan speed CO2 in the exhaust fumes (normal function range) Heater dimensions Control range Against 0.5 mbar 1 kW 2 kW 5.0. 8.0 9.0. 12.5
+5. +35 C (+41. +95 F) max. 93 m3/h (55 cfm) at 4750 rpm 5.0. 8.0 9.0. 12.5
Length mm (12.24 0.08 in.) Width mm (4.72 0.04 in.) Height mm (4.76 0.04 in.) 2.6 kg (5.73 lb)

Weight

Version

17. Version

Air Top 2000 ST B (Gasoline) Air heater for gasoline (12 V) Air Top 2000 ST D (Diesel) Air heater for Diesel/heating oil (12 or 24 V)

18. Drilling Template

Drilling Template
Figure 33. Drilling Template (Dimensions in millimeters)

Appendices

19. Appendices

19.1 Bio-diesel Fuels

Webasto Product N.A., Inc. 15083 North Road Fenton, MI 48430 Technical Assistance Hotline USA: (800) 860-7866 Canada: (800) 667-8900 Org. 03/2006 Rev. 6/2010 P/N 5001118A www.webasto.us www.techwebasto.com