Webasto Thermo Pro 90 Instruction manual

Water Heaters Workshop Manual
Thermo Pro 90
Thermo Pro 90 12 V Diesel - ADR
Thermo Pro 90 24 V Diesel - ADR
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Improper installation or repair of Webasto heating and cooling systems can cause fire or
the leakage of deadly carbon monoxide leading to serious injury or death.
To install and repair Webasto heating and cooling systems you need to have completed a
Webasto training course and have the appropriate technical documentation, special tools
and special equipment.
Only genuine Webasto parts may be used. See also Webasto air and water heaters
accessories catalogue.
NEVER try to install or repair Webasto heating or cooling systems if you have not completed
a Webasto training course, you do not have the necessary technical skills and you do not
have the technical documentation, tools and equipment available to ensure that you can
complete the installation and repair work properly.
ALWAYS carefully follow Webasto installation and repair instructions and heed all
WARNINGS.
Webasto rejects any liability for problems and damage caused by the system being installed
by untrained personnel.
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Thermo Pro 90 Table of Contents
I
Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.1 Contents and purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.2 Meaning of signal words. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.3 Additional documentation to be used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.4 General safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.4.1 Statutory regulations governing installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.4.2 General safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
1.5 Spare parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
2 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
2.1 Combustion air fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
2.2 Heat exchanger. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
2.2.1 Coolant temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
2.2.2 Overheating protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
2.3 Burner unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
2.3.1 Glow plug. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
2.4 Combustion pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
2.5 Exhaust temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
2.6 Circulation pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
2.7 Control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
2.8 Metering pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
3 Description of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
3.1 Switching on and residual-heat utilisation phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
3.2 Starting and control mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
3.3 Switch off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
3.4 Functions of heater in ADR vehicles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
4 Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401
5 Faults, Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
5.1 Troubleshooting without error code output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
5.2 Troubleshooting with error code output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
5.2.1 Error code output with Webasto Thermo Test PC Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
5.2.2 Error code output without Webasto Thermo Test PC Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . 507
5.3 Visual inspection for evaluation of burner unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
5.3.1 Metal fibre evaporator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
5.3.2 Combustion chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
5.3.3 Entire burner unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
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Table of Contents Thermo Pro 90
II
6 Operating tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
6.2 Operating checks in vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
6.3 Adjusting CO2 content. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
6.4 Checking individual components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
6.4.1 Resistance test of coolant temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
6.4.2 Resistance test of glow plug. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
6.4.3 Resistance test of exhaust temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
6.4.4 Testing combustion air fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
6.4.5 Testing DP42 metering pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603
6.4.6 Testing overheating protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603
6.4.7 Testing circulation pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603
7 Circuit diagrams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 701
8 Servicing work. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.1 Work on heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.2 Work on vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.3 Test run of heater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.4 Checking work. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.5 Heater, removal and installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.5.1 Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.5.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
8.6 Recommissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
9 Maintaining and Replacing Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
9.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
9.2 Measures on components when dismantled. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
9.3 Disconnecting electrical connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
9.4 Replacing circulation pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
9.5 Replacing overheating protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903
9.6 Replacing coolant temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903
9.7 Replacing combustion air fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905
9.8 Replacing burner unit and glow plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906
9.9 Replacing burner head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 907
9.10 Replacing heat exchanger. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 908
9.11 Replacing control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 908
9.12 Replacing exhaust temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 908
10 Packing, Storage and Shipping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
10.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
10.2 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
10.3 Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
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Thermo Pro 90 Table of Illustrations
III
Table of Illustrations
Fig. 201 Thermo Pro 90 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Fig. 202 Combustion air fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Fig. 203 Heat exchanger. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Fig. 204 Burner unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Fig. 205 Burner head with combustion pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Fig. 206 Exhaust temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Fig. 207 Circulation pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Fig. 301 Operating sequence of Thermo Pro 90 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
Fig. 501 Overview of possible faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
Fig. 502 Overview of functional test of heater and its components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
Fig. 503 Error code output by standard timer/switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
Fig. 504 Visual inspection, rear wall of burner. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
Fig. 505 Visual inspection, entire burner unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
Fig. 601 CO2 adjustment value (permissible from 10.5 to 14.1 vol. %) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
Fig. 701 Connector assignment on control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 701
Fig. 702 Positioning of electrical components on heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 701
Fig. 703 Wiring diagram for Thermo Pro 90, parking heater with standard timer without ADR. . . . . . . . . . . . . . . 703
Fig. 704 Circuit diagram for Thermo Pro 90, parking heater with On/Off switch without ADR. . . . . . . . . . . . . . . . 704
Fig. 705 Circuit diagram for Thermo Pro 90, parking heater with On/Off switch with ADR with auxiliary drive. . . . 705
Fig. 706 Circuit diagram for Thermo Pro 90, parking heater with On/Off switch with ADR without auxiliary drive. 706
Fig. 901 Replacing circulation pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
Fig. 902 Replacing overheating protection and coolant temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904
Fig. 903 Replacing combustion air fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905
Fig. 904 Replacing burner unit, glow plug, burner head and exhaust temperature sensor . . . . . . . . . . . . . . . . . . . 907
Fig. 905 permissible bending angle and permissible load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
Fig. 906 Testing mica disc (insulation) on sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
Fig. 1001 Preferred position of Thermo Pro 90 heater for storage and transport . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
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1Introduction Thermo Pro 90
101
1 Introduction
1.1 Contents and purpose
This workshop manual serves to support instructed person-
nel, which repairs the Thermo Pro 90 water heater.
1.2 Meaning of signal words
Throughout this manual, the signal words WARNING,
IMPORTANT and NOTE have the following meanings:
WARNING
This heading is used to highlight operating instructions or
procedures which, if not or not correctly followed, may
result in personal injury or fatal accidents.
IMPORTANT
This heading is used to highlight operating instructions or
procedures which, if not or not correctly followed, may
result in damage to the equipment or its components.
NOTE
This heading is used to direct your attention to a special fea-
ture deemed essential to highlight.
1.3 Additional documentation to be used
This workshop manual contains all necessary information
and instructions for the repair of Thermo Pro 90 water heat-
ers.
Information of the general installation and operating
instructions is not contained in this workshop manual. If
repairs are necessary, these documents must also be used.
1.4 General safety precautions
In principle, the general accident prevention regulations and
current works safety instructions are applicable.
"General safety precautions" which go beyond the scope of
these regulations are listed in the following.
Any special safety regulations relevant to this instruction
manual will be highlighted in the relevant sections or text
passages of the procedures.
1.4.1 Statutory regulations governing
installation
Homologation approvals according to the EC Directives 72/
245/EEC (EMC), ECE-R 10 (EMC), 2001/56/EC (Heating) and
ECE R-122 (Heating) and ECE R-10 03 (EMC) exist for the
Thermo Pro 90 heater.
For the installation, primarily the regulations of Appendix VII
of the Directive 2001/56/EC and the regulations contained
in the installation instructions must be observed.
NOTE:
The regulations of these guidelines are binding in the scope
of the EU Directive 70/156/EEC and/or EC/2007/46 (for new
vehicle models from 29/04/2009) and should also be
observed in countries in which there are no special regula-
tions!
The Thermo Pro 90 water heater was designed for use in
commercial vehicles. The applicable regulations must be
taken into account when installing in special vehicles. Other
uses must be clarified with Webasto in advance.
1.4.2 General safety precautions
The repair and commissioning of the unit may only be car-
ried out by personnel trained by Webasto. The repair and
installation of the unit may only be carried by trained experts
in accordance with the workshop manual and the installa-
tion instructions.
The year of initial start-up must be permanently
marked on the type label by removing the inapplica-
ble years.
The heaters are approved for heating the motor vehicle
engine and the vehicle cab, however not for heating the
hazardous-material cargo area.
The heater may only be installed in motor vehicles or in inde-
pendent heating systems with a minimum coolant quantity
of 6 litres.
The heater may not be installed in the cab or the passenger
compartment of vehicles. If the heater is nevertheless
installed in an area of this type, then the installation box
must be sealed off tight to the vehicle interior. The installa-
tion box must be sufficiently ventilated from the outside so
that a maximum temperature of 60 °C is not exceeded in
the installation box. Malfunctions can occur if this tempera-
ture is exceeded.
When checking the coolant level, the procedure described
by the vehicle manufacturer must be followed.
Non-compliance with the installation instructions and the
warnings contained therein will lead to the exclusion of all
liability by Webasto. The same applies if repairs are carried
out incorrectly or with the use of parts other than genuine
spare parts. This will result in the invalidation of the General
Type Approval for the heater and therefore of the General
Homologation of the vehicle.
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Thermo Pro 90 1Introduction
102
WARNING
The heater must not be operated:
• In filling stations and tank farms.
• At locations at which highly flammable gases or dusts
can form, and at which highly flammable liquids or solid
materials are stored (e.g. near fuel, coal and wood dust,
grain warehouses, dry grass and leaves, cardboard ,
paper, etc.).
• In enclosed rooms (e.g. garages), not even via the timer
or Telestart.
• Without at least 33 % brand name anti-freeze in the
water of the heating circuit.
There is a danger of burns, as the heater and the
attached parts may be extremely hot.
The heater including the control unit:
• may not be exposed to storage temperatures of more
than +125 °C. The operating voltage may be connected
at the time. Otherwise the electronics may suffer
permanent damage.
• may only be operated with the fuel specified on the type
label and at the nominal voltage specified on the type
label.
• must be shut down by immediately switching off the
heater and removing the fuse in case of heavy smoke,
unusual combustion noises or fuel odours. The heater
must not be restarted until the unit has been checked
exclusively by personnel duly trained by Webasto.
• must be switched off during work in the engine
compartment and may not be cleaned with high-
pressure cleaning units or compressed air.
• Must be put into operation at least once a year for 10
minutes with the engine cold and the lowest fan speed
selected.
• Must be checked by a professional every 2 years, at the
commencement of the heating period.
Liability:
• Non-compliance with the installation/operating
instructions and the warnings contained therein will
lead to the exclusion of all liability by Webasto. The
same applies if repairs are carried out incorrectly or with
the use of parts other than genuine spare parts. This will
result in the invalidation of the type approval for the
heater and therefore of its homologation/EC type
licence.
Be sure to read the operating instructions of the heater
before commissioning.
1.5 Spare parts
The ID numbers of available spare parts can be found in the
Webasto spare parts catalogue or online in the dealer portal
at http://dealers.webasto.com.
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2 General description Thermo Pro 90
201
2 General description
The Thermo Pro 90 water heater is used in conjunction with
the original vehicle heating system in the parking heating
mode for
– cab and engine preheating,
– utilisation of residual vehicle engine heat.
The auxiliary heating mode can also be operated with the
vehicle engine running.
Depending on the equipment, the ADR function is intended
for the 12 V and 24 V variant.
The water heater operates independently of the vehicle
engine and is connected to the cooling system, the fuel sys-
tem and the electrical system of the vehicle.
The heater runs in controlled intermittent operation accord-
ing to the coolant temperature.
Depending on the deviation of the current coolant temper-
ature from the set-point temperature at the coolant temper-
ature sensor, the burner output is controlled within a range
of 1.8 to 7.6 kW. In case of a particularly high heating
capacity requirement (preheating), the maximum output of
9.1 kW is available for 2 hours when the unit is switched on.
The Thermo Pro 90 heater mainly consists of the following
components:
– Combustion air fan
– Heat exchanger
– Burner unit
– Circulation pump
The following components are arranged in the heater for
control and monitoring:
– Control unit
– Exhaust temperature sensor
– Glow plug
– Coolant temperature sensor
– Overheating protection.
The burner motor speed is monitored with a sensor located
in the control unit. Operation with a separate control unit is
therefore not possible.
The fuel supply is provided from an external source via a
metering pump, which is connected to the fuel system of
the vehicle.
Fig. 201 Thermo Pro 90
4
1 = Combustion air fan
2 = Fuel connection
3 = Coolant temperature sensor
4 = Overheating protection
5 = Heat exchanger
6 = Inlet, coolant
7 = Circulation pump
8 = Outlet, coolant
9 = Exhaust temperature sensor
10 = Outlet, exhaust gas
11 = Inlet, combustion air
12 = Control unit
5
6
7891112
12 3
10
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Thermo Pro 90 2 General description
202
2.1 Combustion air fan
The combustion air fan feeds the air required for combus-
tion to the burner unit.
2.2 Heat exchanger
The heat generated in the heat exchanger by combustion is
transferred to the coolant circuit.
2.2.1 Coolant temperature sensor
The coolant temperature sensor detects the coolant temper-
ature at the coolant outlet of the heater as an electrical
resistance. This signal is fed to the control unit, where it is
processed.
2.2.2 Overheating protection
The overheating protection (bi-metal) protects the heater
against impermissibly high operating temperatures. The
overheating protection reacts at a heat transfer temperature
above 127 ± 7 °C and switches off the heater.
The overheating protection is reset automatically at temper-
atures below 65 ± 5 °C.
2.3 Burner unit
The evaporation and pre-combustion of the fuel take place
in the burner unit.
2.3.1 Glow plug
The fuel-air mixture is ignited with the glow plug when the
heater is started. The glow plug is positioned axially in the
centre of the burner unit.
Fig. 202 Combustion air fan
Fig. 203 Heat exchanger
4
3
3 = Coolant temperature sensor
4 = Overheating protection
Fig. 204 Burner unit
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2 General description Thermo Pro 90
203
2.4 Combustion pipe
The combustion pipe supports the combustion of the fuel-
air mixture, and as a result partially also the heating of the
heat exchanger.
2.5 Exhaust temperature sensor
The exhaust temperature sensor (ATS) is used to detect the
flame and impermissible exhaust temperatures.
2.6 Circulation pump
The circulation pump ensures the pumping of the coolant in
the vehicle and/or heater circuit. The pump is switched on
via the control unit and runs during the entire operating
phase (even in the control break, during run-on and during
the residual heat utilisation phase) of the heater.
2.7 Control unit
The control unit ensures the operating sequence and the
monitoring of combustion operation.
2.8 Metering pump
The metering pump is used for the heater fuel supply. In
addition, it also serves as a shut-off system with the heater
switched off.
The magnetic coil of the metering pump receives the pulses
from the microprocessor of the control unit.
Fig. 205 Burner head with combustion pipe
Fig. 206 Exhaust temperature sensor
Combustion pipe
Fig. 207 Circulation pump
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Thermo Pro 90 3 Description of Operation
301
3 Description of Operation
3.1 Switching on and residual-heat utilisation phase
The heater is switched on depending on the equipment
variant by means of a switch or standard timer.
Activating residual-heat utilisation phase
The coolant temperature is checked by the heater each time
the heater is switched on, before the heating process. If the
coolant temperature is above 60 °C, the residual-heat
utilisation phase is activated automatically. When the
residual-heat utilisation phase is active, the circulation pump
of the heater and the vehicle fan are controlled
automatically.
The activation of the residual-heat utilisation phase can only
take place from the “OFF” state, i.e. in the “residual-heat
utilisation phase“ state, there is no transition from the states
"Fault lock-out", "ADR lock-out" and "Heater lock-out".
Deactivating residual-heat utilisation phase
The residual-heat utilisation phase is deactivated:
a) when the lower limit of the operating voltage is reached
b) when the coolant outlet temperature is below 40 °C
c) when the heater is switched off.
If the criteria a) or c) are met when activating the residual-
heat utilisation phase or during the residual-heat utilisation
phase, then there is a transition to the “OFF" state.
Fig. 301 Operating sequence of Thermo Pro 90
Glow plug
Meteringpump
Combustion air
fan
Exhaust
temperature
sensor
Operating
indicator lamp
Circulation pump
Vehicle fan
1) Switching on
2) Component check
3) Preheating 40 s.
4) Metering pump/partial load (1/4)
5) "Flame ON" detection
6) Stabilisation time
7) Full load
8) Vehicle fan "On"
9) Control range
10) Control break
11) "Flame OFF” detection
12) Run-on ended
13) Preheating 15 to 20 sec.
14) Metering pump/partial load (1/4)
15) "Flame ON" detection
16) Stabilisation time
17) Coolant temperature dropped
18) Full load
19) Switching off (run-on)
20) "Flame OFF” detection
21) Run-on ended
Possible encodable control temperatures
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3 Description of Operation Thermo Pro 90
302
If the criterion b) is met during the activation of the residual-
heat utilisation phase or during the residual-heat utilisation
phase, then the heater is automatically started.
3.2 Starting and control mode
After combustion begins (start), controlled heating
automatically begins.
At a low coolant temperature, the boost heating capacity of
9.1 kW can be run for a maximum of 2 hours.
At a higher coolant temperature, the heating capacity is
modulated between 1.8 kW and 7.6 kW. The objective to
achieve and maintain the control temperature.
The original vehicle heater fan does not switch until the
coolant is sufficiently heated (from approx. 30 °C).
If the coolant temperature increases above the set-point
value of the control temperature, and further to the control
break threshold, the heater switches into the control break.
The circulation pump, the original vehicle heater fan and the
operation indicator continue to operate during the control
break.
The heater starts again automatically after the coolant has
cooled to the pre-encoded restart temperature.
3.3 Switch off
When the heater is switched off, the operation indicator on
the standard timer/switch goes out. Combustion is ended
and the run-on begins. However, the circulation pump, the
glow plug and the combustion air fan continue to run
during the run-on time to cool the heater. It is permissible
to switch on the heater again during the run-on. However,
restarting does not take place until after the run-on is
complete.
3.4 Functions of heater in ADR vehicles
The heater is put into operation with the switch. An ADR
case (forced switch-off) is triggered if
– the vehicle engine is shut down
(generator signal (D+) is eliminated),
– a pumping device is put into operation (auxiliary drive
signal (NA) is active).
In this case, combustion is ended and a reduced run-on, i.e.
the ADR run-on, is initiated. 40 seconds after the ADR case
occurs, the ADR run-on is ended.
Then the heater is in the "ADR lock-out" state. Before
restarting, the On/Off switch must be set to "Off" and the
auxiliary drive signal may no longer be active.
The isolating switch (Emergency-Stop switch) may only be
operated in case of danger, as the heater is switched off
without any run-on (overheating possible).
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Thermo Pro 90 4TechnicalData
401
4TechnicalData
Heater Operation Thermo Pro 90
12 V 24 V
Approval symbol E1 122R 00 0320 (Heater)
E1 10R 03 6196 (EMC)
Model Water heater with evaporator-type burner
Heat output Max.
Control range 9.1 kW 1.8 to 7.6 kW
Fuel Diesel DIN EN 590
PME DIN EN 14214
Fuel consumption
±10% Max. Control range 1.14 l/h 0.21 to 0.92 l/h
Rated voltage 12 V 24 V
Operating voltage range 10.5 to 14.7 V 20 to 29 V
Nominal power consumption with circulation
pump
± 10 % (without vehicle fan)
Max.
Control range
≤90 W
37 to 83 W
Perm. ambient temp.:
Heater incl. control unit:
- Operation
- Storage
Metering pump:
- Operation
- Storage
-40 to +80 °C
-40 to +125 °C
(heater off, operating voltage may be connected)
-40 to +30 °C
-40 to +85 °C
Perm. operating gauge pressure (coolant) 2.5 bar
Capacity of the heat exchanger 0.15 l
Max. combustion-air intake temperature +40 °C
Max. fuel temperature +30 °C
Minimum quantity of coolant circuit 6.00 l
Delivery rate of the circulation pump against 0.15
bar 1,650 l/h
CO2in exhaust gas (perm. function range) 8 to 13 vol. %
CO2adjustment values at approx. +20 °C and
geodetic altitude of 0 m above sea level 10.5 vol. %
Heater dimensions
* From control unit to inlet connection piece of
circulation pump
Also see Fig. 2.
(Tolerance ±3mm)
L = Length: 355 (381*) mm
W = Width: 131 mm
H = Height: 232 mm
Weight 5.25 kg
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5 Faults, Troubleshooting Thermo Pro 90
501
5 Faults, Troubleshooting
General
This section describes troubleshooting on the Thermo Pro 90
heater.
IMPORTANT
Troubleshooting work demands precise knowledge of the
structure and theory of operation of the various compo-
nents and must be carried out by trained personnel only.
In case of questions, the functional relationships are
described in Section 2 or 3.
IMPORTANT
Error detection is generally limited to the localisation of the
defective components. The following fault causes are not
taken into account and should always be checked or a fault
should be excluded for the following reasons:
• Corrosion on connector
• Loose contact on connector
• Crimping error on connector
• Corrosion on lines and fuses
• Corrosion on battery terminals
• Impermissible high ambient temperature
Each time an error is eliminated, a functional check must be
carried out in the vehicle; switch the heater off and on again
beforehand.
Procedure in case of errors or faults and lock-outs
IMPORTANT
Always determine the error cause for the lock-out first, then
eliminate the lock-out.
If errors occur in the heater, they will be detected by the
control unit as a fault. Depending on the type and weight-
ing of the fault, a fault run-on can be initiated. When a fault
run-on is initiated, the heater remains in the fault lock-out.
In addition, a error code is output after a fault is detected
during the fault switch-off.
The error code is displayed via:
– the operation indicator or
– the "ON/OFF" switch or
– Reading out of the error memory with Webasto Thermo
Test PC Diagnosis.
The error code is used by the workshop or the authorised
Webasto dealer for troubleshooting.
NOTE
In the Webasto Thermo Test PC Diagnosis, W bus must be
selected under “Diagnosis” => “Device selection”. It is rec-
ommended that the operating and fault data and the
extended fault environment conditions be printed out.
Fault causes
A fault occurs when one or more error have occurred. Pos-
sible errors are, e.g.
– Overvoltage/undervoltage
– Malfunctions of all components, e.g. due to a short cir-
cuit or open circuit
– Overheating of the heater
– Impermissible exhaust temperature
– False starts
– Flame failures
Elimination of faults without Webasto Thermo Test PC
Diagnosis
Switch on heater (switch/standard timer)
An error has occurred and is detected by the control unit
as a relevant fault
Heater switches off due to the error, i.e. fault switch-off
with subsequent fault lock-out.
The error code is output with the switch/standard timer.
Determine error cause (e.g. with or without error code
output, visual inspection of fuses and connectors, etc.)
Eliminate error
Switch off heater
Switch on heater
Fault lock-out unlocked
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Thermo Pro 90 5 Faults, Troubleshooting
502
Elimination of faults with Webasto Thermo Test PC
Diagnosis
Certain errors result in the errors being added up in the error
memory. If the number of errors in the error memory has
exceeded a limit, the heater changes over to the heater lock-
out. The maximum number of errors in the error memory or
the error memory limit is defined by Webasto.
Heater lock-out
With Webasto Thermo Test PC Diagnosis
Is unlocked as follows:
1. Switch on heater (switch/standard timer or with
"Parking Heating“ button)
2. Clear the error memory with the "Clear fault memory
and heater interlock" command in the "Error memory"
menu.
3. Delete the heater lock-out by clicking the "Delete
heater lock-out" button in the "Error memory" menu
4. Switch off heater (switch/standard timer) or with
"Parking Heating“ button of heater
Without Webasto Thermo Test PC Diagnosis
Is unlocked as follows:
1. Switch on heater (switch/standard timer)
2. At the latest 10 s after switching on, remove the fuse F3
for at least 10 s.
3. Reinstall fuse F3
4. Switch off heater
Switch on heater (switch/standard timer or with
"Parking Heating“ button)
An error has occurred and is detected by the control unit
as a relevant fault
Heater switches off due to the error, i.e. fault switch-off
with subsequent fault lock-out.
Determine cause of error by reading out error memory!
The error memory is read out by clicking the "Error list"
button.
Always print error memory first or note!
Then clear error memory with the "Clear fault memory
and heater interlock" command in the "Error memory"
menu.
Eliminate error
Switch off heater
Switch on heater
Fault lock-out unlocked
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5 Faults, Troubleshooting Thermo Pro 90
503
5.1 Troubleshooting without error code output
Possible faults
The overview only shows some of the possible faults. The Webasto Service Hotline must be contacted in individual cases.
IMPORTANT
The error points specified from Tables Fig. 501 and Fig. 502 DO NOT match the error code numbers for error code output!
Functional test of heater and its components
Heater Mode Fault Description Possible error point
(see Table Fig. 502)
Start Heater does not react, no component starts up, no display by opera-
tion indicator
6, 8
Heater does not start, short start-up, then changes into run-on imme-
diately, operation indicator flashes (error code output)
1, 2, 3, 4, 5, 10
Heater smokes in start-up phase 2, 9, 10, 12, 15, 19
Combustion
operation
Heater runs through start, however switches off prematurely 7, 9, 10, 12, 13, 15, 19, 20
Heater has rough combustion 9, 12, 19
Heater smokes in heating phase 9, 12, 15, 19, 21
Heater runs, vehicle interior cold 17
Run-on Heater smokes in run-on phase 15, 19
Other Fuel odour 1, 2, 12
Exhaust odour in vehicle interior 16
Coolant loss 11, 14
Fig. 501 Overview of possible faults
Error point Component Recommended workshop action Parameter
1 DP42 metering
pump
Check continuity and seating of flat spring contacts
of metering pump line
Measure cold resistance of DP42 metering pump at
25 °C, also see Section 6.4.5
4.95 to 5.45 ohms, Test
current: < 1 mA
2 Glow plug Measure glow-plug resistance value on glow plug
connector X2, also see Section 6.4.2
Cold resistance at 25 °C:
– 0.235 to 0.305 ohms for
the 12 V variant
– 0.670 to 0.870 ohms for
the 24 V variant ("green"
marking on glow plug)
3 Coolant tem-
perature sensor
For information on checking the cold resistance of
the coolant temperature sensor, also see Section
6.4.1
At 25 °C:
990 to 1,010 ohms, Test
current: < 1 mA
Fig. 502 Overview of functional test of heater and its components
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Thermo Pro 90 5 Faults, Troubleshooting
504
4 Combustion air
fan
Combustion air fan short circuit/open circuit
Check fan wiring and replace component if neces-
sary
5 U4840 circula-
tion pump
Check wiring
Conduct component test to check function of circu-
lation pump with Webasto Thermo Test PC Diagno-
sis.
Touch pump with hand;
pump functions if slight
vibration or running can be
felt
Check self-bleeding installation position, also see
Section 8.5.2
6 Power supply With Webasto Thermo Test PC Diagnosis
Measure operating voltage from Webasto Thermo
Test PC Diagnosis
Check fuse F1
Check power supply
Without Webasto Thermo Test PC Diagnosis
Measure power supply on heater unit connector X8,
Pin 12 (also see Fig. 703, Fig. 704 and Fig. 705)
7 Undervoltage
detection
With Webasto Thermo Test PC Diagnosis
Measure operating voltage from Webasto Thermo
Test PC Diagnosis
– 12 V variant:
The voltage may not
drop below 10.5 V for
more than 10
consecutive seconds
– 24 V variant:
The voltage may not
drop below 20.0 V for
more than 10
consecutive seconds
– Check fuse F1
Without Webasto Thermo Test PC Diagnosis
Measure power supply on heater unit connector X8,
Pin 12 (also see Fig. 703, Fig. 704 and Fig. 705)
8 Operation indi-
cator
(standard timer
or ON/OFF
switch)
When the immediate heat button/switch is operated,
the light in the display/switch is activated
Operation indicator of
standard timer:
– Measure power supply
on connector X9, Pin 11
– Check continuity on
connector X9, Pin 12 to
earth
– Check fuse F2
Operation indicator of
switch:
– Measure power supply
on switch S4, Pin A
– Check continuity on
switch S4, Pin F to earth
– Check fuse F2
9 DP42 metering
pump
Measure fuel feed rate (use Webasto Thermo Test PC
Diagnosis for controlling the metering pump), also
see Section 6.4.5
Diesel feed rate at metering
pump frequency of 9 Hz and
feed time of 180 s:
49.5 to 54.7 ml
Check fuel line connection to DP42 metering pump
Error point Component Recommended workshop action Parameter
Fig. 502 Overview of functional test of heater and its components
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5 Faults, Troubleshooting Thermo Pro 90
505
10 Combustion air
fan
Combustion air fan sluggish.
Conduct component test on function of fan motor
with Webasto Thermo Test PC Diagnosis.
– Specify a set-point
speed of 6,000 rpm
– Listen for rubbing and
friction noises.
In addition, start-up
must be audible up to
the specified speed
– No "Sluggish fan start"
fault message may be
output
11 U4846 circula-
tion pump
Check pump for leaks
12 Fuel
connection
Observe fuel fill level and fuel removal from tank
Check integration in vehicle fuel system
Check fuel lines for leaks, kinking and clogging,
especially in the area of the intake-side line connec-
tors
Disconnect the fuel line from the heater, hold the
hose in a catch container and operate the metering
pump with the Webasto Thermo Test PC Diagnosis
for 180 s at 9 Hz. When doing so, watch whether
the fuel is pumped bubble-free
If fuel sprays out of the line when the line is sepa-
rated from the heater, the fuel pipe of the burner
unit is probably clogged. If this is the case, the burner
unit must be replaced.
13 Coolant circuit Check the integration in the vehicle coolant circuit in
accordance with the general installation instructions
Check whether coolant circuit is correctly bled
Check circulation in coolant circuit
14 Coolant circuit Eliminate kinks and rubbing spots
Check leaks on heater, water connection piece, cir-
culation pump and hoses and eliminate
15 Exhaust system
and air intake
system
Check whether intake pipe and exhaust pipe are
routed in accordance with general installation
instructions
Check to make sure lines are not clogged
Eliminate existing leaks on intake pipe and exhaust
pipe (no CO2in intake air)
The exhaust pipe outlet may not be routed under the
intake pipe inlet
16 Exhaust system
and air intake
system
Check whether sufficient distance is present to pas-
senger compartment fresh-air intake of vehicle
No exhaust gas may be
sucked in through the com-
bustion air pipe
Error point Component Recommended workshop action Parameter
Fig. 502 Overview of functional test of heater and its components
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Thermo Pro 90 5 Faults, Troubleshooting
506
17 Vehicle fan Check fuse F1
Observe coolant temperature (K5 switches at
approx. 25 °C)
Check switching signal on the relay K5, ground on
Pin 85 and positive on Pin 86 (audible, also see wiring
diagram in general installation instructions)
Check coolant temperature signal wire (green/white,
gn/wh), Pin 86 on K5
18 Control unit/
heater locked
Determine error cause for lock-out, then eliminate
lock-out.
A distinction is made between 3 types of lock-out:
– Fault lock-out
Unlocking by pressing ON/OFF switch
–ADRlock-out
See Fault lock-out
When ADR is triggered by the auxiliary drive, it
must be deactivated before switching on the
heater again
– Heater lock-out
Unlock:
1) Switch on heater (with switch or standard
timer)
2) Remove fuse F3 for at least 10 s.
3) Switch off heater (only with switch).
4) Reinstall fuse F3.
19 Burner unit Dismantling and visual inspection
20 Sooting:
Exhaust gas
temperature
has increased
to maximum
permissible
value.
Dismantling and visual inspection of burner unit,
exhaust temperature sensor, combustion pipe and
heat exchanger
Clean or completely replace
depending on condition
21 Optional room
thermostat
Room thermostat B4 does not switch Clean or replace compo-
nents
Check connection
Error point Component Recommended workshop action Parameter
Fig. 502 Overview of functional test of heater and its components
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