Water Heaters Workshop Manual
Thermo Top Evo
Type Thermo Top Evo (Petrol)
Type Thermo Top Evo (Diesel)
Improper installation or repair of Webasto heating and cooling systems can cause fire or
the leakage of deadly carbon monoxide leading to serious injury or death.
To install and repair Webasto heating and cooling systems you need to have completed a
Webasto training course and have the appropriate technical documentation, special tools
and special equipment.
Only genuine Webasto parts may be used. See also Webasto air and water heaters
accessories catalogue.
NEVER try to install or repair Webasto heating or cooling systems if you have not completed
a Webasto training course, you do not have the necessary technical skills and you do not
have the technical documentation, tools and equipment available to ensure that you can
complete the installation and repair work properly.
ALWAYS carefully follow Webasto installation and repair instructions and heed all
WARNINGS.
Webasto rejects any liability for problems and damage caused by the system being installed
by untrained personnel.
Thermo Top Evo 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 Safety precautions and regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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 unit/control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
2.2 Burner unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
2.2.1 Glow plug/Flame monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
2.3 Heat exchanger. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
2.3.1 Temperature sensor and overheating sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
2.4 Circulation pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
2.5 Metering pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
2.6 Heater controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
3 Description of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
3.1 Switching on/starting process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
3.2 Heating mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
3.3 Restarting after fault lock-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
3.4 Starting after long period of non-use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
3.5 Switching off/Switch-off function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
4 Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401
5 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
5.1 Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
5.1.1 Fault lock-out and heater lock-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
5.1.2 Fault lock-out due to undervoltage or overvoltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
5.1.3 Fault release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
5.2 General fault symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
5.3 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
5.4 Reading out fault memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
5.5 Component fault entered in the fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
5.6 General faults entered in fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505
5.7 Faults without fault entry in control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
6 Operating tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
6.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
6.2 Operating checks in vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
Table of Contents Thermo Top Evo
II
7 Circuit diagrams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 701
8 Servicing work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.1 Work on the heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.2 CO
2
setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.3 Circulation pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
8.4 DP42 metering pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
8.5 Checking work. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
8.6 Heater, removal and installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
8.6.1 Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
8.6.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803
8.7 Recommissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803
9 Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
9.1 Dismantling and assembling heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
9.1.1 Dismantling heater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903
9.1.2 Assembling heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903
9.2 Burner unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903
9.2.1 Removing burner unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903
9.2.2 Installing burner unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904
9.3 Glow plug/Flame monitor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905
9.3.1 Electrical test of glow plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905
9.3.2 Removing glow plug/flame monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905
9.3.3 Installing glow plug/flame monitor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906
9.4 Combustion-air fan unit and control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 907
9.5 Heat exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 907
9.6 Checking sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 908
9.7 Water connection piece . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
9.7.1 Installing water connection piece Variant A - without lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
10 Packing, Storage and Shipping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
10.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
10.2 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
10.3 Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
Thermo Top Evo List of illustrations
III
List of illustrations
Fig. 201 Thermo Top Evo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Fig. 202 Combustion-air fan unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Fig. 203 Burner unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Fig. 204 Heat exchanger. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Fig. 205 U4847 Econ circulation pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Fig. 206 DP42 metering pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Fig. 207 Digital timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Fig. 208 Telestart T91 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Fig. 209 Telestart T100 HTM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Fig. 210 Thermo Call TC 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Fig. 301 Functional illustration of Thermo Top Evo heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
Fig. 501 Overview of component faults entered in the fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
Fig. 502 Overview of general faults entered in fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505
Fig. 503 Overview of possible faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
Fig. 504 Overview of functional test of heater and its components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 512
Fig. 701 Wiring diagram of Thermo Top Evo parking heater and 12 V digital timer. . . . . . . . . . . . . . . . . . . . . . . . 702
Fig. 801 CO2 setting values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
Fig. 802 Installation position of U4847 Econ circulation pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
Fig. 803 Pumping quantity of DP42 metering pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
Fig. 804 Installation position of DP42 metering pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
Fig. 901 Component illustration of Thermo Top Evo heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
Fig. 902 Burner unit and combustion-air fan unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903
Fig. 903 Detailed illustration of cable routing for glow plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904
Fig. 904 Petrol burner unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904
Fig. 905 Diesel burner unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904
Fig. 906 Burner unit with glow plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905
Fig. 907 Remove retaining spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905
Fig. 908 Remove cooling flag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905
Fig. 909 Remove glow plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905
Fig. 910 Installing glow plug. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906
Fig. 911 Installing cooling flag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906
Fig. 912 Installing retaining spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906
Fig. 913 Installing glow plug properly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906
Fig. 914 Installing glow plug. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906
Fig. 915 Routing glow plug cable with slight bend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906
Fig. 916 Combustion-air fan unit with illustration of connectors
(variant shown is equipped with the maximum connector assignment) . . . . . . . . . . . . . . . . . . . . . . . . . . 907
Fig. 917 Heat exchanger. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 907
Fig. 918 Position retaining spring
while watching cable routing and position of sensors W5 and W6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 908
Fig. 919 Sensor resistance values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 908
Fig. 920 Comparison of retaining plates without (above) and with (below) lock . . . . . . . . . . . . . . . . . . . . . . . . . . 909
Fig. 921 Retaining plate for installing water connection piece . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
Fig. 1001 Preferred position for Thermo Top Evo heater for storage and transport . . . . . . . . . . . . . . . . . . . . . . . . 1001
1Introduction Thermo Top Evo
101
1 Introduction
1.1 Contents and purpose
This workshop manual is used to support trained personnel
which repairs the petrol and diesel models of the Thermo
Top Evo parking heater water heaters and auxiliary heaters.
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 Top Evo water
heaters.
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 Safety precautions and regulations
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
Type approvals according to ECE-R 10 (EMC) and ECE-
R 122 (Heater) exist for the Thermo Top Evo heater.
For the installation, primarily the regulations of the directive
ECE-R 122 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 Top Evo water heaters were designed for instal-
lation in Class M1 motor vehicles. The installation in motor
vehicles of the classes O, N2, N3 and hazardous substance
transports according to the EC Directive EEC/70/156 and/or
Basic Directive EC/2007/46 is not permissible.
The applicable regulations must be taken into account when
installing in special vehicles. Other uses are possible in con-
sultation with Webasto.
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 mar-
ked on the type label by removing the inapplicable
years.
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 locations 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 20 % 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.
Thermo Top Evo 1Introduction
102
The heater:
• may not be subjected to temperatures of more than
120 °C (storage temperature). otherwise the electronics
may suffer permanent damage.
• may only be operated with the fuel and 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 operating instructions and the
warnings contained therein will lead to the exclusion of
all liability by Webasto.
The same also applies if repairs are not undertaken by
professionals or without using genuine spare parts. This
invalidates the type approval for the heater and its
homologation/ECE type permit.
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 at
http://dealers.webasto.com.
NOTE
Before ordering the spare part, please make sure that the
parking heater has been equipped as a parking-auxiliary
heater (e.g. by reading out the EOL data record with
Webasto Thermo Test PC Diagnosis).
2 General description Thermo Top Evo
201
2 General description
The Thermo Top Evo water heater is used to compensate
the heat deficit which results with consumption-optimised
vehicle engines.
The Thermo Top Evo parking heater is used:
– to heat the passenger compartment,
– to defrost the vehicle windows,
– to preheat water-cooled vehicle engines.
The Thermo Top Evo auxiliary heater can be upgraded to a
parking-auxiliary heater with an additional kit.
As the external appearance is identical, the heaters are
marked with "Petrol" or "Diesel on the type label; there is
no special marking for the auxiliary heater. The heaters may
only be operated with the predetermined fuel and only with
the respectively specified type of electrical connection.
NOTE
This workshop manual describes the retrofit variant of the
heater. For heaters installed directly at the vehicle manufac-
turer's plant, other control units with other connectors and
other software and other application parts may be used
which are not described in this manual. Information is only
available for these heaters via the documentation of the
vehicle manufacturer.
The heater designed according to the evaporator principle
operates in the full-load and partial-load mode, controlled
by the temperature sensor.
The heater consists of the combustion-air fan unit (G) with
the control unit, the heat exchanger (W) with the water con-
nection piece and the burner.
Fig. 201 Thermo Top Evo
G
G = Combustion air fan assembly
W = Heat exchanger assembly
W
Thermo Top Evo 2 General description
202
2.1 Combustion-air fan unit/control unit
The combustion-air fan unit contains:
• the heater type label
• the connection piece for the combustion air pipe
• the control unit with the plug-in contacts
• the engine and the impeller
The combustion air fan supplies the air required for the
combustion process from the combustion air inlet to the
combustion chamber.
NOTE
It is not permissible to dismantle the combustion-air fan
unit.
2.2 Burner unit
The fuel-air mixture is processed and the actual combustion
takes place in the burner unit. The fuel flows via the fuel
pipe to the evaporator, is distributed there and is evapo-
rated using the glow plug. The air required for combustion
is provided by the combustion-air fan unit and flows into the
combustion chamber via holes in the burner.
Fig. 202 Combustion-air fan unit
Fig. 203 Burner unit
B1
B1 = Combustion pipe with
evaporator mount and
evaporator
B2 = Retaining spring for glow
plug
B3 = Cooling flag for glow
plug
B4 = Glow plug/Flame monitor
B5 = Fuel pipe
B9 = Connector for glow plug/
flame monitor
B4
B2 B3
B5
B9
Pin 1
Pin 2
2 General description Thermo Top Evo
203
2.2.1 Glow plug/Flame monitor
The glow plug/flame monitor is connected to the control
unit (SG) via an electrical line with a connector (B9). The
glow plug is fastened to the evaporator mount with a
retaining spring (B2). A cooling flag (B3) provides for heat
dissipation from the glow plug, and therefore reduces the
temperature at the glow-plug connection lines.
The glow plug ignites the fuel-air mixture in the start-up
phase and is switched off after the "full load" state is
reached. From this point it is used exclusively for flame mon-
itoring. If the flame extinguishes, the electrical resistance in
the glow plug drops as the result of the missing heat appli-
cation. This is detected in the control unit.
2.3 Heat exchanger
The heat generated in the heat exchanger by combustion is
transferred to the coolant circuit.
2.3.1 Temperature sensor and overheating sen-
sor
The temperature sensor detects the coolant temperature in
the heat exchanger of the heater as an electrical resistance.
This signal is fed to the control unit, where it is processed.
The temperature sensor (W5) and the overheating sensor
(W6) for a unit together with the cable and the connector.
The overheating sensor protects the heater against imper-
missibly high operating temperatures. This reacts at a tem-
perature above 125 °C and switches off the heater.
2.4 Circulation pump
The U4847 Econ circulation pump ensures a feed rate of the
coolant in the vehicle heater and heater circuit. The pump is
switched on with the control unit and runs during the entire
operation of the heater. The circulation pump is a centrifu-
gal pump with a brushless EC motor.
The circulation pump is equipped with a 2-pin connector
output and is connected to the control unit (SG) by means
of a separate wiring harness. The circulation pump must not
be used after being dropped.
2.5 Metering pump
The fuel metering pump is a combined pumping, metering
and shut-off system. This dry-primeable reciprocating piston
pump pumps the fuel from the vehicle fuel tank to the fuel
connection piece of the heater via fuel lines. Installation is
usually carried out near the fuel tank. The metering pump
contains no pulsation damper and is equally well-suited for
diesel and petrol. The metering pump is connected to the
control unit via the heater-unit wiring harness and to an
earthing point on the vehicle body.
IMPORTANT
Only the model DP42 fuel metering pump may be used for
the Thermo Top Evo heater. Observe the model designation
on the component for this purpose. When replacing the
metering pump, the CO
2
settings must be checked. See
Section 8.2.
Fig. 204 Heat exchanger
W2 W5 W4 W3
W6
W1
W1 = Heat exchanger
W2 = Cable of temperature sensors
W3 = Ejomat DG 40x10 self-tapping screw
W4 = Retaining spring for sensors
W5 = Temperature sensor
W6 = Overheating sensor
Fig. 205 U4847 Econ circulation pump
Thermo Top Evo 2 General description
204
2.6 Heater controls
NOTE
Additional information on the respective heater control is
contained in the specific installation and operating instruc-
tions.
Fig. 206 DP42 metering pump
Fig. 207 Digital timer
Fig. 208 Telestart T91
Fig. 209 Telestart T100 HTM
Fig. 210 Thermo Call TC 3
3 Description of operation Thermo Top Evo
301
3 Description of operation
3.1 Switching on/starting process
The heater is started with the parking heater via a switch-on
signal of the heater control. And with the auxiliary heater
when the auxiliary heating signal is present at the heater
unit inlet. The auxiliary heating signal is dependent on pre-
viously defined switch-on conditions, such as the outside
temperature (below 5 °C) and engine running.
NOTE
The Thermo Top Evo heaters described in this manual can
only be put into operation with a W-bus-capable heater
control, or with the Webasto Thermo Test PC Diagnosis.
With the Webasto Thermo Test PC Diagnosis connected, the
connection to other heater controls is disconnected.
Different configuration options are shown in the system wir-
ing diagram.
When the heater is started up, the combustion air fan, the
circulation pump and the glow plug are put into operation.
Then the metering pump is connected. The petrol heater
starts up at the highest load level. In contrast, the diesel
heater starts up at a low load level and is slowly adjusted
upward to full load in the form of a ramp.
During this start-up phase, it is checked whether a flame has
formed with the glow plug.
If no flame is detected or the flame extinguishes, then auto-
matic restarting can be initiated. If no flame is formed once
again, the starting attempt is ended. Then a fault lock-out is
carried out with run-on of the combustion air fan. The
heater cannot be restarted until after switch-off.
Depending on the coolant temperature, the control unit
decides which starting process is selected. Start-up proc-
esses are identical with regard to the sequence, however
differ in the length of the individual phases (preheating, fuel
delivery, etc.).
3.2 Heating mode
After full load is reached, the glow plug assumes the func-
tion of the flame monitor and checks the flame. The heater
switches into the energy-saving partial-load mode after a
certain temperature (around 80 °C) is reached. If the tem-
perature continues to increase, the heater switches into the
control break from a pre determined temperature (approx.
84 °C).
After the coolant has cooled down, the heater restarts in the
partial-load mode. If the temperature rises to a defined
switching temperature again, the heater switches into the
control break again. If the temperature of the coolant con-
tinues to drop due to an increased heat requirement during
partial load operation, then the heater switches over to full
load operation again.
The temperature of the switching points is programmed in
the control unit.
If a flame out occurs during normal combustion operation,
a restart is automatically initiated.
Fig. 301 Functional illustration of Thermo Top Evo heater
Thermo Top Evo 3 Description of operation
302
3.3 Restarting after fault lock-out
After the fault cause has been eliminated, the heater must
be switched on again with the normal switch-on signals.
This does not apply after overheating or if a fault occurs sev-
eral times without intermediate combustion operation.
3.4 Starting after long period of non-use
Longer periods of non-use have no effect on the starting
function of the heater. However, limitations must be made
here with regard to filling of the fuel lines. Especially with
petrol heaters, the fuel evaporates from the fuel line in the
summer months. As a result, it must be expected that sev-
eral complete starting attempts will be required for initial
starting. Commissioning must them be carried out with the
Webasto Thermo Test PC Diagnosis.
Prime the heater with fuel using the Webasto Thermo Test
PC Diagnosis:
Press the fill line button and fill the lines until fuel is present
at the heater.
3.5 Switching off/Switch-off function
When a switch-off signal is received, when the burn-out
temperature is reached, when the set heating time is
reached or if faults occur, combustion operation is ended
and a burn-out is initiated. In the process, the control of the
fuel metering pump is immediately interrupted and the fan
speed is decreased. After the burn-out is complete the fan
speed is increased to cool the combustion chamber.
NOTE
The run-on time and the combustion-air fan speed are
dependent on the heater model and operating mode from
which the heater is switched off.
Switch-off or new switch-on signals are processed accord-
ing to the following rules:
1. A switch-off signal on a heater control always as priority
irrespective of the heater operating state.
2. If the original switch-on signal is no longer active, or if
the included heating duration has expired, then this is
interpreted as a switch-off signal.
3. New switch-on signals are ignored until the original
switch-on signal is no longer active.
4. It is therefore not possible to change the heating time
during operation. The heater must be switched off and
then on again with the changed heating duration.
5. If the heater has been started as an auxiliary heater, then
switching off the vehicle engine must be interpreted as
a switch-off signal (legal requirement).
6. A restart of the heater is not possible until after the burn-
out has completed and the first cooling phase (forced
run-on) has been ended. New switch-on signals are tem-
porarily stored and are not followed until then.
4 Technical Data Thermo Top Evo
401
4 Technical Data
The technical data is contained in the installation instructions.
Thermo Top Evo 5 Troubleshooting
501
5 Troubleshooting
5.1 Faults
5.1.1 Fault lock-out and heater lock-out
Faults which occur are assigned to various categories:
Fault
1) A fault which occurs has no effect on the current
combustion operation; an fault message is stored.
2) A fault which occurs causes automatic restarting or a
restart; a fault message is stored.
Fault lock-out
3) A fault which occurs in the power supply or in the
control unit results in an immediate heater switch-off
without burn-out. No fault is entered.
4) A fault which occurs results in a heater switch-off (burn-
out) or prevents heater start-up; a fault message is
stored. Restarting requires a switch-off signal and a
repeat switch-on signal.
Permanent heater lock-out due to multiple repetitions of
an fault
5) If a fault from 4) occurs 6 times consecutively without
the full load state being reached, then the heater is
locked out and a fault message is stored.
The lock-out can only be cancelled at the workshop.
If the fault is an undervoltage switch-off due to a weak
battery, then no lock-out occurs.
Overheating lock-out (heater is overheated)
6) The heater overheats and is locked out; a fault message
is stored.
The lock-out can only be cancelled at the workshop.
NOTE
If a fault lock-out and a subsequent heater lock-out occurs,
then no display occurs on the heater controls. A start-up of
the heater is permitted; a fault is no longer present.
In case of a heater lock-out, the heater is locked out and
cannot be switched on.
5.1.2 Fault lock-out due to undervoltage or
overvoltage
In case of an undervoltage of 11.5 V for a certain period
(20 sec.), a fault lock-out with a run-on occurs. The specified
undervoltage is software-dependent and is measured at the
control unit input.
In case of an overvoltage of 16.0 V (measured on the
heater) for a certain period (5 sec.), a fault lock-out with
run-on also occurs.
5.1.3 Fault release
After the fault cause is eliminated, the fault release is carried
out by switching the heater off and then on again.
IMPORTANT
A permanent heater lock-out/overheating lock-out can only
be cancelled with the Webasto Thermo Test PC Diagnosis.
The heater faults stored in the fault memory must be read
out and printed with the Webasto Thermo Test PC Diagno-
sis. To delete the heater lock-out without clearing the fault
memory, select the menu command Fault memory/Delete
heater lock-out.
In exceptional cases, the heater lock-out can be cancelled by
disconnecting the power supply of the control unit (e.g. by
removing the fuse F1, 20 A for at least 10 seconds). The
fault must be eliminated beforehand. (See Section 5.3). The
fuse must be pulled within 10 sec. after switching on the
heater.
5.2 General fault symptoms
The following chapter contains a general overview of the
fault symptoms with the heater installed.
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.
5 Troubleshooting Thermo Top Evo
502
5.3 Troubleshooting
Possible fault during heater operation are sorted in this
chapter according to the following criteria:
1) Component faults entered in the fault memory (see
Section 5.5).
A specific component which is defective is contained in
the control-unit fault memory. The component or next-
highest assembly must be replaced.
2) General faults entered in the fault memory (see
Section 5.6).
The heater has detected a problem (e.g. no starting),
however cannot identify the specific cause.
Troubleshooting is structured so that the periphery of
the heater is checked (e.g. the fuel supply) before the
heater or a sub-component is replaced.
3) Fault without fault entry in the control unit (see
Section 5.7).
Troubleshooting is structured so that the periphery of
the heater is checked (e.g. the fuel supply) before the
heater or a sub-component is replaced.
5.4 Reading out fault memory
The fault memory of the heater can be read out with the
Webasto Thermo Test PC Diagnosis.
The fault memory displays up to 8 different faults. The older
an fault is, the higher its number. The current operating
duration and the current start-up number are entered in the
control unit summary.
If a fault is entered as "current" then the control unit has
discovered this fault since the last switch-on.
The fault message "Initial starting attempt failed" remains
current until either full-load combustion operation is
achieved in the restart or the second start-up also fails. In
this case, the fault message "Initial starting attempt failed"
is deleted and replaced with "No start".
The fault message "Flame abort" remains current until the
heater is switched off or several flame aborts lead to the
heating mode being aborted. In this case, the fault message
"Flame abort" is deleted and replaced with "Flame failure".
NOTE
The operation of the diagnostic unit is explained in the oper-
ating instructions. W bus must be entered under Heater
model.
It is recommended that the operating and fault data and the
extended fault environment conditions be printed out.
Thermo Top Evo 5 Troubleshooting
503
5.5 Component fault entered in the fault memory
Fault
code
(HEX)
Fault
code
(DEZ)
WTT* fault message Fault details with double-
click in WTT*
Recommended workshop
action
00 - No error No error No activity required
01 1 Defective control unit Defective control unit, off-line
programming is not per-
formed\or water temperature
sensor defective
Delete fault, carry out fault
release/heater lock-out on heater
(see Section 5.1.1), restart heater
08 8 Metering pump short cir-
cuit
Metering pump has short cir-
cuit to ground
Conduct electrical test of fuel sys-
tem (see Section 5.7, Fig. 504,
Point 5)
0B 11 Circulation pump short cir-
cuit
The connected line of the
water pump has a short circuit
to earth\nor the engine is over-
loaded
Conduct electrical test of coolant
system (see Section 5.7, Fig. 504,
Point 9)
10 16 Coolant changeover valve
short circuit
The coolant changeover valve
has a short circuit to earth
Conduct electrical test of coolant
changeover valve (see
Section 5.7, Fig. 504, Point 16)
13 19 Vehicle fan power circuit
short circuit
The vehicle fan power circuit
has a short circuit to earth
Conduct troubleshooting in area
of vehicle fan (see Section 5.7,
Fig. 504, Point 13)
15 21 Combustion air fan
blocked
Combustion air fan is blocked 1 Conduct troubleshooting in
combustion air fan (see
Section 5.7, Fig. 504, Point 8)
2 Conduct troubleshooting in
intake air system (foreign
body) (see Section 5.7, Fig.
504, Point 12)
19 25 Glow/ignition element
power circuit short circuit
Glow plug / electronic ignition
unit has short circuit to ground
Conduct electrical test of glow
plug (see Section 5.7, Fig. 504,
Point 6)
1B 27 Overheat sensor short cir-
cuit
The connected line of the ele-
ment has a short circuit to
earth
Conduct electrical test of temper-
ature sensors (see Section 5.7, Fig.
504, Point 7)
2D 45 The combustion-air fan
power circuit is defective
Fan motor speed is below
value to be expected
Delete fault, carry out fault
release/heater lock-out on heater
(see Section 5.1.1), restart heater
2E 46 The glow/ignition-element
power circuit is defective
Glow plug resistance is outside
the value range
In case of multiple occurrences
(> 3):
1) Troubleshooting in air intake
or in exhaust system (see
Section 5.7, Fig. 504, Point 12)
2) Conduct electrical test of glow
plug (see Section 5.7, Fig. 504,
Point 6)
Fig. 501 Overview of component faults entered in the fault memory
5 Troubleshooting Thermo Top Evo
504
* WTT = Webasto Thermo Test PC Diagnosis
3A 58 W-bus/LIN-bus short cir-
cuit to earth
No additional information
available
Troubleshooting in area of W bus
communication (see Section 5.7,
Fig. 504, Point 2 and 3)
3C 60 Internal control unit fault
60
No additional information
available
Delete fault, carry out fault
release/heater lock-out on heater
(see Section 5.1.1), restart heater
3D 61 Internal control unit error
61
No additional information
available
Delete fault, carry out fault
release/heater lock-out on heater
(see Section 5.1.1), restart heater
3E 62 Internal control unit error
62
No additional information
available
Delete fault, carry out fault
release/heater lock-out on heater
(see Section 5.1.1), restart heater
3F 63 Wrong version dataset
loaded
No additional information
available
Delete fault, carry out fault
release/heater lock-out on heater
(see Section 5.1.1), restart heater
40 64 Glow plug / electronic
ignition unit - glow
filament interruption
One of the heating circuits of
the glow plug/electronic igni-
tion unit is open
– Check glow plug (see
Section 9.3.2)
– Replace control unit (combus-
tion-air fan unit) or heater
81 129 EOL checksum error Checksum of EOL dataset is
wrong
Delete fault, carry out fault
release/heater lock-out on heater
(see Section 5.1.1), restart heater
88 136 Metering pump interrup-
tion
Metering pump interrupted or
short circuit to supply voltage
+Ub
Conduct electrical test of fuel sys-
tem (see Section 5.7, Fig. 504,
Point 5)
89 137 Combustion air fan inter-
ruption
Combustion air fan inter-
rupted or short circuit to sup-
ply voltage +Ub
Troubleshooting in combustion
air fan (see Section 5.7, Fig. 504,
Point 8)
8B 139 Circulation pump inter-
ruption
Circulation pump interrupted
or short circuit to supply volt-
age +Ub
Conduct electrical test of coolant
system (see Section 5.7, Fig. 504,
Point 9)
90 144 Coolant changeover valve
open circuit
The coolant changeover valve
power circuit is open\nor has a
short circuit to +Ub
Conduct electrical test of coolant
changeover valve (see
Section 5.7, Fig. 504, Point 16)
94 148 Temperature sensor inter-
ruption
Temperature sensor inter-
rupted or short circuit to sup-
ply voltage +Ub
Conduct electrical test of temper-
ature sensors (see Section 5.7, Fig.
504, Point 7)
99 153 Glow plug / electronic
ignition unit interruption
Glow plug / electronic ignition
unit interrupted or short circuit
to supply voltage +Ub
Conduct electrical test of glow
plug (see Section 5.7, Fig. 504,
Point 6)
AB 171 Overheat sensor interrup-
tion
Overheat sensor interrupted or
short circuit to supply voltage
+Ub
Conduct electrical test of temper-
ature sensors (see Section 5.7, Fig.
504, Point 7)
Fault
code
(HEX)
Fault
code
(DEZ)
WTT* fault message Fault details with double-
click in WTT*
Recommended workshop
action
Fig. 501 Overview of component faults entered in the fault memory
Thermo Top Evo 5 Troubleshooting
505
5.6 General faults entered in fault memory
Fault
code
(HEX)
Fault
code
(DEZ)
WTT* fault message Fault details with double-
click in WTT*
Recommended workshop
action
00 No error No error No activity required
02 2 No start After start-up has been
repeated, combustion still fails
to occur
1) Troubleshooting in air
intake or in exhaust system
(see Section 5.7, Fig. 504,
Point 12)
2) Conduct troubleshooting
in fuel system (see
Section 5.7, Fig. 504,
Point 10)
3) Conduct check of metering
pump (see Section 5.7, Fig.
504, Point 5)
4) Conduct electrical test of
glow plug (see Section 5.7,
Fig. 504, Point 6)
04 4 Supply voltage too high Supply voltage was too long
above maximum threshold value
Conduct check of vehicle elec-
trical-system supply voltage
(also see Section 5.7, Fig. 504,
Point 1)
05 5 Flame was detected prior to
combustion
Flame detector signals flame
before combustion operation
1) Troubleshooting in air
intake or in exhaust system
(see Section 5.7, Fig. 504,
Point 12)
2) Conduct troubleshooting
in fuel system (see
Section 5.7, Fig. 504,
Point 5)
3) Conduct electrical test of
glow plug (see Section 5.7,
Fig. 504, Point 6)
06 6 Heating unit overheated Overheat protection was
released
1) Check vehicle coolant cir-
cuit (see Section 5.7, Fig.
504, Point 11)
2) Check circulation pump
(see Section 5.7, Fig. 504,
Point 9)
3) Conduct electrical test of
temperature sensors (see
Section 5.7, Fig. 504,
Point 7)
4) Check heater for visible
damage and leaks, then
check coolant circuit for
leaks. Then put heater into
operation again.
Fig. 502 Overview of general faults entered in fault memory
5 Troubleshooting Thermo Top Evo
506
11 17 ECU wrong coded Incorrect parameter block or
wrong heater (diesel/gasoline)
used
This fault can only occur on
vehicles with CAN bus or LIN
bus connection to heater:
1) Compare heater type label
with vehicle fuel type
2) Proceed according to vehi-
cle manufacturer's specifi-
cations
12 18 W bus communication fail-
ure
Bus fault, protocol error Operation continues
unchanged if this fault occurs.
In case of frequent occurrence
(> 10) and faults in heater
operation:
1 Troubleshooting in area of
W bus communication/Tel-
estart receiver (see
Section 5.7, Fig. 504,
Point 2, and 3)
2) Replace control unit (com-
bustion-air fan unit) or
heater
2F 47 Flame abort The flame has extinguished dur-
ing operation. Another starting
attempt will be carried out.
In case of frequent occurrence
(> 10):
1) Troubleshooting in air
intake or in exhaust system
(see Section 5.7, Fig. 504,
Point 12)
2) Conduct troubleshooting
in fuel system (see
Section 5.7, Fig. 504,
Point 10)
3) Conduct check of metering
pump (see Section 5.7, Fig.
504, Point 5)
4) Conduct electrical test of
glow plug (see Section 5.7,
Fig. 504, Point 6)
37 55 Coolant temperature during
initial start-up too high
No additional information avail-
able
This fault can only occur dur-
ing initial start up of the heater
(at vehicle manufacturer's
plant):
1) Allow coolant system to
cool down - attempt initial
start-up again
2) Conduct electrical test of
temperature sensors (see
Section 5.7, Fig. 504,
Point 7)
Fault
code
(HEX)
Fault
code
(DEZ)
WTT* fault message Fault details with double-
click in WTT*
Recommended workshop
action
Fig. 502 Overview of general faults entered in fault memory
Thermo Top Evo 5 Troubleshooting
507
38 56 Initial starting attempt failed No additional information avail-
able
In case of frequent occurrence
(> 10):
1) Troubleshooting in air
intake or in exhaust system
(see Section 5.7, Fig. 504,
Point 12)
2) Conduct troubleshooting
in fuel system (see
Section 5.7, Fig. 504,
Point 10)
3) Conduct check of metering
pump (see Section 5.7, Fig.
504, Point 5)
4) Conduct electrical test of
glow plug (see Section 5.7,
Fig. 504, Point 6)
39 57 Initial starting attempt failed
– not restarting
No additional information avail-
able
In case of frequent occurrence
(> 3):
1) Troubleshooting in air
intake or in exhaust system
(see Section 5.7, Fig. 504,
Point 12)
2) Conduct troubleshooting
in fuel system (see
Section 5.7, Fig. 504,
Point 10)
3) Conduct check of metering
pump (see Section 5.7, Fig.
504, Point 5)
4) Conduct electrical test of
glow plug (see Section 5.7,
Fig. 504, Point 6)
3F 63 Wrong version dataset
loaded
No additional information avail-
able
Delete fault, carry out fault
release/heater lock-out on
heater (see Section 5.1.1),
restart heater
4C 76 Overvoltage component
protection
Switching off at extremely high
overvoltage for component pro-
tection
Conduct check of vehicle elec-
trical-system supply voltage
(also see Section 5.7, Fig. 504,
Point 1)
Fault
code
(HEX)
Fault
code
(DEZ)
WTT* fault message Fault details with double-
click in WTT*
Recommended workshop
action
Fig. 502 Overview of general faults entered in fault memory
5 Troubleshooting Thermo Top Evo
508
4E 78 Customer specific fault 3 No additional information avail-
able
In case of frequent occurrence
(> 3):
1) Troubleshooting in air
intake or in exhaust system
(see Section 5.7, Fig. 504,
Point 12)
2) Conduct troubleshooting
in fuel system (see
Section 5.7, Fig. 504,
Point 10)
3) Conduct check of metering
pump (see Section 5.7, Fig.
504, Point 5)
4) Conduct electrical test of
glow plug (see Section 5.7,
Fig. 504, Point 6)
81 129 EOL checksum error Checksum of EOL dataset is
wrong
Delete fault, carry out fault
release/heater lock-out on
heater (see Section 5.1.1),
restart heater
82 130 No start during testrun No start during testrun This fault can only occur dur-
ing initial start up of the heater
(at vehicle manufacturer's
plant):
1) Troubleshooting in air
intake or in exhaust system
(see Section 5.7, Fig. 504,
Point 12)
2) Conduct troubleshooting
in fuel system (see
Section 5.7, Fig. 504,
Point 10)
3) Conduct check of metering
pump (see Section 5.7, Fig.
504, Point 5)
4) Conduct electrical test of
glow plug (see Section 5.7,
Fig. 504, Point 6)
Fault
code
(HEX)
Fault
code
(DEZ)
WTT* fault message Fault details with double-
click in WTT*
Recommended workshop
action
Fig. 502 Overview of general faults entered in fault memory
Thermo Top Evo 5 Troubleshooting
509
83 131 Flame failure Flame interruption during com-
bustion operation, more than
FAZ (EEPROM) times
In case of frequent occurrence
(> 3):
1) Troubleshooting in air
intake or in exhaust system
(see Section 5.7, Fig. 504,
Point 12)
2) Conduct troubleshooting
in fuel system (see
Section 5.7, Fig. 504,
Point 10)
3) Conduct check of metering
pump (see Section 5.7, Fig.
504, Point 5)
4) Conduct electrical test of
glow plug (see Section 5.7,
Fig. 504, Point 6)
84 132 Operating voltage too low Supply voltage was too long
below maximum threshold value
1) Check approximate for-
mula: Does the customer
heat longer than his/her
driving time?
2) Conduct check of vehicle
electrical-system supply
voltage (also see
Section 5.7, Fig. 504,
Point 1)
86 134 Excessive water tempera-
ture without combustion
process
Fault will be set if water temper-
ature has exceeded 145 °C in
control break
In case of multiple occurrences
(> 3):
1) Troubleshooting in coolant
system (see Section 5.1)
and bleed system
2) Conduct check of tempera-
ture sensors (see
Section 5.7, Fig. 504,
Point 7)
3) Replace heater
87 135 Heater lock-out permanent Permanent heater lock-out has
been activated
1) Delete heater lock-out -
attempt restart
2) Read out additional fault
messages and work
through their recommen-
dation for action
92 146 Command refresh failure Command refresh failure. In
case of this fault no operation
Troubleshooting in area of W
bus communication (see
Section 5.7, Fig. 504, Point 2,
3 and 4)
Fault
code
(HEX)
Fault
code
(DEZ)
WTT* fault message Fault details with double-
click in WTT*
Recommended workshop
action
Fig. 502 Overview of general faults entered in fault memory
5 Troubleshooting Thermo Top Evo
510
* WTT = Webasto Thermo Test PC Diagnosis
9C 156 Heating time exceeded Calculated heating time from
intelligent undervoltage detec-
tion exceeded
1) Check approximate for-
mula: Does the customer
heat longer than his/her
driving time?
2) Check vehicle electrical-
system supply voltage
A9 169 Insufficient coolant flow The fault occurs if the coolant
temperature exceeds the switch-
ing threshold for burning out
during the phases Start/GPR
(glow plug ramp)/FMM (flame
monitor measuring phase) dur-
ing the control break
1) Check vehicle coolant cir-
cuit (see Section 5.7, Fig.
504, Point 11)
2) Check circulation pump
(see Section 5.7, Fig. 504,
Point 9)
3) Conduct electrical test of
temperature sensors (see
Section 5.7, Fig. 504,
Point 7)
4) Check heater for visible
damage and leaks, then
check coolant circuit for
leaks.
Then put heater into oper-
ation again.
AA 170 S on W-Bus not succeed S on W-Bus not succeed (nor or
faulty response, even after
repeating telegram four times)
Troubleshooting in area of W
bus communication (see
Section 5.7, Fig. 504, Point 2,
3 and 4)
AB 171 Overheat sensor interrup-
tion
Overheat sensor interrupted or
short circuit to supply voltage
+Ub
Conduct electrical test of tem-
perature sensors (see
Section 5.7, Fig. 504, Point 7)
Fault
code
(HEX)
Fault
code
(DEZ)
WTT* fault message Fault details with double-
click in WTT*
Recommended workshop
action
Fig. 502 Overview of general faults entered in fault memory
Thermo Top Evo 5 Troubleshooting
511
5.7 Faults without fault entry in control unit
NOTE
Before each repair on the heater, the fault memory must be
read out with the Webasto Thermo Test PC Diagnosis. Exist-
ing faults must be printed before deleting and made availa-
ble to the Webasto Hotline or the Warranty Department.
At low temperatures and with no wind, a minor amount of
smoke and/or a slight odour may be noticeable during start-
ing and/or burn-out.
The occurrence of fog with an exhaust system not warmed
through or in case of unfavourable weather conditions is
normal and cannot be avoided.
Smoke: exits directly from the exhaust end section.
Fog: becomes visible just a few centimetres after
the exhaust tailpipe.
Possible faults
The overview only shows some of the possible faults. The
Webasto Service Hotline must be contacted in individual
cases.
Fault Description Possible fault
point
(see Table Fig. 504)
Heater does not react 1, 2, 3, 4, 14
Heater does not heat 5, 6, 7, 8, 10, 12
Heater switches off prematurely 1, 5, 7, 10, 12
Heater has intermittent combus-
tion
5, 8, 10, 12
Heater smokes in start-up phase 5, 8, 10, 12
Telestart cannot be tuned 1, 3, 4, 14
Heater running, vehicle passen-
ger compartment cold
7, 9, 11, 13, 16
Heater smokes in heating phase/
white smoke
5, 7, 8, 10, 12
Heater smokes in run-on phase 5, 10, 12
Fuel odour 5, 6, 7, 8, 10, 12
Exhaust odour in passenger com-
partment
5, 6, 7, 8, 10, 12
Coolant loss 9, 11
Fig. 503 Overview of possible faults
5 Troubleshooting Thermo Top Evo
512
Functional test of heater and its components
Fault Component Recommended workshop action Parameter
1Power supply
Measure supply voltage under load at heater unit
connector X2 (also see Fig. 916)
Undervoltage switch-off
<11.5V
2Clock
Press flame button, display lighting must light up
LED flickers when button is
pressed
Check the W bus signal on Pin 2 on heater unit con-
nector X1 or diagnostic connector with an LED lamp
against "+"
3
Receiver
(Telestart T91
and T100 HTM)
Check the W bus signal on the 6-pin connector on
the receiver, Pin 2, with an LED lamp against Pin 1
"+"
LED flickers when On button
is pressed
4
Transmitter
(Telestart)
Assign transmitter to receiver/teach in accordance
with instructions
Check operating mode on Telestart hand-held trans-
mitter (heat/ventilate)
Battery of hand-held transmitter should have suffi-
cient capacity (new)
5 Metering pump
Check continuity from connector X1, Pin 6 to con-
nector X7 (blue wire)
Check continuity from connector X7 (brown wire) to
earth
Measure coil resistance of DP42 metering pump
5.20 ohms ± 0.5 % at
20 ± 2 °C
Measure feed rate with Webasto Thermo Test PC
Diagnosis, also see Section 8.4
Petrol feed rate:
7 Hz, 60 sec: 11.6 to
14.3 ml
Diesel feed rate:
7 Hz, 60 sec: 12.0 to
14.6 ml
Check connection of fuel line on connection piece in
accordance with general installation instructions
6 Glow plug
Measure glow plug resistance on glow plug connec-
tor X5 (white wire), also see Section 9.3.1
At 25 ± 5 °C:
0,235 to 0.355 ohms
7
Temperature
sensors
For information on checking the cold resistance of
the sensors, also see Section 9.6
At 20 ± 6 °C:
W5 (Pin 2 and 4)
2,296 to 5,047 ohms
W6 (Pin 1 and 3)
30 to 250 ohms
8
Combustion air
fan
Conduct component test on function of fan motor
with Webasto Thermo Test PC Diagnosis.
No rubbing noises may be heard.
Check CO
2
settings in accordance with Section 8.2
Fig. 504 Overview of functional test of heater and its components
Thermo Top Evo 5 Troubleshooting
513
9
Circulation
pump
Conduct component test to check function of circu-
lation pump with Webasto Thermo Test PC Diagno-
sis.
Touch with hand; pump
functions if slight vibration
can be felt
Measure resistance on circulation pump connector
X4, also see Section 8.2
10 ± 1 kohms
Check pump for leaks
Check self-venting installation position, also see
Section 8.3 or general installation instructions
10 Fuel integration
Are bubbles visible in the fuel line/are bubbles
pumped during feed rate test (see Point 5)?
If they are, then change connection or routing of
line.
Check integration in vehicle fuel system.
Observe fuel level (no reserve); is fuel tank extraction
correct?
Inspect fuel lines for leaks, kinking or clogging.
11 Coolant circuit
Check integration in coolant circuit of motor vehicle
in accordance with general installation instructions/
vehicle-specific installation instructions
Check whether coolant circuit is correctly bled
Check circulation in coolant circuit
Eliminate kinks and rubbing spots
Check leaks on heater, water connection piece, cir-
culation pump and hoses and eliminate
Check whether coolant mixing ratio is suitable e.g. down to -40 °C
12
Exhaust system
and intake air
system
Check whether intake pipe and exhaust pipe are
routed in accordance with general installation
instructions/vehicle-specific installation instructions
Check to make sure lines are not clogged
Eliminate existing leaks on intake pipe and exhaust
pipe (no CO
2
in intake air)
Check whether sufficient distance is present to pas-
senger compartment fresh-air intake of vehicle
13 Vehicle fan
Check switching signal on relay K1, Pin 86 (also see
wiring diagram in general installation instructions/
vehicle-specific installation instructions)
Observe coolant temperature (K1 switches at
approx. 50 °C)
Check flap position of vehicle heater (air condition-
ing set to HI)
14
Control unit/
heater locked
Unlock in accordance with Section 5.1.3
Fault Component Recommended workshop action Parameter
Fig. 504 Overview of functional test of heater and its components
5 Troubleshooting Thermo Top Evo
514
15
Control unit
(fault memory)
Read out fault memory with Webasto Thermo Test
PC Diagnosis, then print out and clear fault memory
Include printed fault log when sending heater to
Webasto.
Complete replacement of fan unit if control unit is
defective.
16
Coolant
changeover
valve
Check continuity from connector X1 Pin 4 to connec-
tor X15.
Check continuity from connector X15 (brown wire)
to earth.
Apply 12 V voltage to connector X1, Pin 4 Valve switches audibly
Fault Component Recommended workshop action Parameter
Fig. 504 Overview of functional test of heater and its components
Thermo Top Evo 5 Troubleshooting
515
6 Operating tests Thermo Top Evo
601
6 Operating tests
6.1 General
This section describes the tests of the heater and its compo-
nents in the installed and the removed state.
6.2 Operating checks in vehicle
1. Set the vehicle van to fan speed 1 - 2 or to the speed rec-
ommended in the vehicle-specific operating instructions.
2. Make sure that the fresh-air inlet is clear of foreign bod-
ies (snow, leaves, etc.) and any pollen and dust filters are
clear.
3. Make sure that the coolant circuit and the fuel system
are carefully bled in accordance with the vehicle manu-
facturer's specifications.
4. Switch on the heater with the heater control.
When the heater is switched on, the circulation pump
and the combustion air fan run. This is audible. The vehi-
cle fan is switched on by the heater when the coolant
temperature has reached 30 to 50 °C (vehicle-specific).
After a maximum of 240 sec, exhaust can be seen exiting
at the exhaust muffler or connection piece.
5. Allow the heater to run in the combustion mode. Check
the heating effect at the outlet nozzles of the vehicle fan.
NOTE
The heating effect is dependent on several factors:
To evaluate it, the outside temperature, the vehicle model,
the engine temperature, the type of integration in the vehi-
cle cooling system, the quantity of coolant to be heated up
and the time since the start must be used for the evaluation.
The coolant temperature determined by the heater and the
coolant or engine temperature indicated by the vehicle may
differ considerably, as the respective sensors are installed at
different locations and may evaluate different tempera-
tures.
6. Switch off the heater again with the heater control.
A maximum run-on of 175 sec is activated when the
heater is switched off. This is audible due to a reduction
of the combustion noise. The continued running of the
combustion air fan with an increase in the speed after
approx. 60 sec is used for active cooling of the heater
and operation of the circulation pump.
This is followed by a complete switch-off.
Thermo Top Evo 7 Circuit diagrams
701
7 Circuit diagrams
Fig. 701 shows the circuit of the Thermo Top Evo heater, parking heater and heater control.
Legend for wiring diagram.
Cable colours
bl
br
ge
gn
gr
or
rt
sw
vi
ws
blue
brown
yellow
green
grey
orange
red
black
violet
white
Item Description Comment
Present in vehicle Vehicle fan
Fan controller
Air-conditioning control unit
Aerial
Plug connection View of Line Side
Indicator for vehicle engine
running (in-line operation of
solenoid coolant valve)
Optional
Must be activated with a
data record
Low active auxiliary heating
request
Optional
Must be activated with a
data record
Gnd/0 V = ON
open or no signal or
U > 6 V = OFF
Outside temperature
X1 6-pin connector Vehicle signal
X2 2-pin connector Power supply
X3 4-pin connector Temperature sensors
X4 2-pin connector Circulation pump
X5 2-pin connector Glow plug
X6 2-pin connector not in use
X7 2-pin connector Metering pump
X8 2-pin connector Diagnosis plug
X9 2-pin connector Diagnosis bridge
X10 4-pin connector Heater controls
X11 4-pin connector Heater controls
X12 4-pin connector Temperature sensor for W
bus
X13 4-pin connector Temperature sensor for W
bus
X14 6-pin connector Telestart T91/T100 HTM
X15 2-pin connector Solenoid coolant valve
Changeover to in-line oper-
ation of solenoid coolant
valve only in conjunction
with 12 V signal on Pin 1
X16 2-pin connector Circulation pump
X17 4-pin connector Telestart button
X18 4-pin connector Telestart button
A1 Heater Thermo Top Evo
A2 Control unit
A3 Digital timer 1533
A4 Telestart T91
A5 Telestart T100 HTM
A6 Fuse holder
A7 W bus temperature sensor
A8 IPCU Fan controller
A9 Relay socket with fuses
A10 Telestart button
F1 Fuse 20 A
F2 Fuse 30 A
F3 Fuse 1 A
F4 Fuse 25 A
B1 Temperature sensor
Coolant temperature sensor
B2 Temperature sensor Overheating
M1 Motor Combustion air fan
M2 Motor Circulation pump
M3 Vehicle fan
S1 Vehicle fan switch
S2 Vehicle fan switch
S3 Switch ON/OFF Optional
S4 Switch for auxiliary heating
request
E Glow plug
Y1 Metering pump DP 42
Y2 Solenoid coolant valve
K1 Relay Fan relay
Item Description Comment
7 Circuit diagrams Thermo Top Evo
702
Fig. 701 Wiring diagram of Thermo Top Evo parking heater and 12 V digital timer.
Thermo Top Evo 8Servicing work
801
8Servicing work
This section describes the servicing work that can be carried
out on the heater and its components while installed.
8.1 Work on the heater
The power supply must always be disconnected at the vehi-
cle battery before carrying out any work on the heater. The
power supply must not be disconnected whilst the heater is
operating or slowing down as a result of the risk of the
heater overheating and the overheating protection thus
being tripped. If repair work is carried out on the heater, it
must be completely removed.
After the heater and all coolant-carrying components have
been installed, the entire coolant system must be filled, bled
and checked for leaks with the specified system pressure in
accordance with the vehicle manufacturer's instructions.
The general installation instructions and the vehicle-specific
installation instructions for the heater must be observed
when carrying out repairs which make it necessary to
change the installation location.
NOTE
Any coolant running off should be collected using an appro-
priate container.
8.2 CO
2
setting
NOTE
After repairing the heater and/or replacing the metering
pump, the setting of the CO
2
value should be checked.
IMPORTANT
After replacing the fan unit or the control unit, the CO
2
value must be checked and reset if necessary.
The CO
2
setting is carried out with Webasto Thermo Test PC
Diagnosis and the CO
2
testers specified by Webasto.
Common AU large gas quantity emission testers cannot be
used for the CO
2
setting of the heater.
The heater is optimally set to a CO
2
value for operation at
altitudes between 0 and 1,000 m above sea level at the fac-
tory. Continuous operation above 1,000 m above sea level
can lead to heavy smoking and formation of soot.
To prevent a failure of the unit and danger, the CO
2
value
should be adjusted in consultation with Webasto.
NOTE
The CO
2
measurement and setting must be carried out in
the full load heater operating mode (display in Webasto
Thermo Test: Full Load). The CO
2
value is corrected in selec-
tion point 2.7.1. CO
2
calibration of Webasto Thermo Test
PC Diagnosis. The measurement of the CO
2
content is car-
ried out approx. 20 mm in front of the end of the exhaust
outlet inside the exhaust pipe with a CO
2
tester (e.g. from
MSI).
The following table shows the nominal CO
2
setting value in
full-load combustion operation in dependence on the geo-
detic altitude at which the setting is made.
8.3 Circulation pump
The power consumption is approx. 12 W with a nominal
volume flow rate of 450 l/h.
Altitude
[m above sea
level]
Nominal CO
2
setting value at
20 °C ambient temperature
[% by vol.]
4kW 5kW
0 8,9 9,5
500 9,5 10,1
1000 10,0 10,7
Fig. 801 CO
2
setting values
8 Servicing work Thermo Top Evo
802
Fig. 802 Installation position of U4847 Econ circulation
pump
NOTE
Ensure the correct direction of flow of the circulation pump
to the vehicle coolant circuit. The installation position of the
circulation pump must be chosen so that the circulation
pump is self-bleeding. It must be possible for the air volume
trapped in the circulation pump to escape upward by itself
via at least one connection piece.
Electrical checking of circulation pump
Internal resistance of the circulation pump: 10 ± 1 kohms
8.4 DP42 metering pump
Check the installation positions and installation conditions
of the metering pump in accordance with the general instal-
lation instructions for the Thermo Top Evo. The Thermo Top
Evo heater may only be operated with the DP42 metering
pump.
Electrical checking of metering pump
Coil resistance of the DP42 metering pump:
5.20 ohms ± 0.5 % at 20 ± 2 °C
Carry out the function component test of metering
pump with Webasto Thermo Test PC-Diagnose.
Fig. 804 Installation position of DP42 metering pump
8.5 Checking work
The following servicing work is to be carried out every two
years at the latest to maintain the functional reliability of the
heater:
• Read out fault memory.
• Inspect electrical connections for contact corrosion and
firm seating.
• Inspect exhaust and combustion air lines for damage
and to ensure that they are clear.
• Check fuel line for leaks.
• Check hoses for cracks.
• Conduct operating test of heater as described in section
6.2.
8.6 Heater, removal and installation
8.6.1 Removal
1 Interrupt power supply of heater by removing 20 A
blade fuse (yellow) from Webasto fuse holder.
2 Disconnect electrical connectors from heater.
3 De-pressurise coolant system.
NOTE
All open plugs and connectors must be protected against
moisture and soiling.
4 Loosen hose clamps and pull coolant hoses off water
connection pieces of heater. The coolant hoses must be
secured against draining.
5 Loose combustion air pipe and exhaust pipe on heater
and pull off.
6 Loosen hose clamps and pull off fuel line. Seal off fuel
connection piece on heater and fuel line with suitable
sealing plugs etc.
7 Detach heater from bracket; remove bracket from body
if necessary.
Setting 7 Hz / 60 sec 7 Hz / 180 sec
Diesel 12.0 to 14.6 ml 36.2 to 44.3 ml
Petrol 11.6 to 14.3 ml 34,9 to 42.8 ml
Fig. 803 Pumping quantity of DP42 metering pump
Thermo Top Evo 8Servicing work
803
8.6.2 Installation
1 Move heater into specified installation position and
tighten heater screws to 8 Nm.
NOTE
The screw must be carefully inserted in the existing threads
and screwed in by hand.
2 Mount fuel line and secure with hose clamp.
3 Mount coolant hoses and secure with clamps.
4 Restore all electrical connections.
5 Connect combustion air pipe and exhaust pipe.
6 Connect vehicle battery.
7 Bleed coolant circuit.
8 Bleed vehicle fuel system if necessary.
IMPORTANT
A polarity reversal of the power supply can result in damage
to the control unit. The correct polarity of the connection
wires must be ensured. A direct connection to a power sup-
ply without an intermediate fuse is not permissible.
8.7 Recommissioning
To support bleeding of the coolant circuit, the circulation
pump must be put into operation via the Component test
function of the Webasto Thermo Test PC Diagnosis.
IMPORTANT
Before the heater is commissioned, the coolant temperature
should be < 30°C, as otherwise the heater may not go into
combustion operation.The heater must be put into opera-
tion with the Webasto Thermo Test PC Diagnosis.
With the fuel line completely drained, the line must be filled
with the Webasto Thermo Test PC Diagnosis: Press the fill
line button and prime line with fuel until fuel is present at
the heater.
All coolant and fuel connections must be checked for leaks
and secure attachment during a trial run of the heater.
9 Repair Thermo Top Evo
901
9 Repair
NOTE
Please see the spare parts list!
NOTE
It is not permissible to change the specified units for the pet-
rol heaters listed below.
NOTE
The seals must always be replaced before assembling the
heater.
For these petrol heaters:
– Thermo Top Evo 4 Petrol
– Thermo Top Evo 5 Petrol
– Thermo Top Evo 5+ Petrol
9021034 A/B
9021032 A/B
9021031 A/B
Change not permissible:
– Combustion-air fan unit/control unit spare parts kit
– Burner unit spare parts kit
Thermo Top Evo 9Repair
902
9.1 Dismantling and assembling heater
Fig. 901 Component illustration of Thermo Top Evo heater
A3
A1
A2 A4 A5
A6
W1
A7BA8SG
G1
A9
A1 = Heater cover
A2 = Screw
A3 = Retaining plate
A4 = Water connection piece
A5 = O-ring
A6 = Screw
A7 = Gasket
A8 = Connector cover
A9 = Cable cover
B = Burner unit
G1 = Fan housing
SG = Control unit
W1= Heat exchanger
9 Repair Thermo Top Evo
903
9.1.1 Dismantling heater
1. Loosen screw (A2, Fig. 901) and remove water connec-
tion piece (A4) with retaining plate (A3) and O-rings
(A5).
2. Loosen heater cover (A1) at side detents on fan hous-
ing (G1) with a screwdriver. Then remove heater cover
(A1) from heater toward front.
3. Remove cable cover (A9) from fan housing (G1).
4. Release connector cover (A8) on side facing away from
fuel connection piece at side detents with a screwdriver
and take off heater.
5. Release latch of connector and pull connector off con-
trol unit (SG).
6. Loosen screws (A6) and pull heat exchanger (W1) off
fan housing (G1) in axial direction of screw fitting.
7. For information on removing the burner unit (B), see
Section 9.2.1.
NOTE
The sensors can be damaged during removal. Once
removed, sensors may not be reinstalled. A new heat
exchanger spare part must be used.
9.1.2 Assembling heater
1. For information on installing burner unit (B) see
Section 9.2.2.
2. Clean heat exchanger (W1) inside and outside and
place on fan. Tighten 3 screws (A6) to 7 ± 0.7 Nm.
3. Insert connectors on control unit (SG) with slight pres-
sure until they are heard and felt to engage.
4. Place connector cover (A8) on control unit (SG) and
engage with slight pressure.
5. Hook heater cover (A1) on heat exchanger (W1) into
heater and engage in locking lugs of fan housing (G1).
6. Lay new O-rings (A5) in heat exchanger (W1) and fas-
ten water connection piece (A4) and retaining plate
(A3) with screw (A2).
Tightening torque 7.5 ±0.7 Nm.
9.2 Burner unit
Fig. 902 Burner unit and combustion-air fan unit
9.2.1 Removing burner unit
Dismantle
heater as described in Section 9.1.1 up to
Point 6. The connectors are disconnected. Set down the fan
with the burner unit vertically.
1. Remove the gasket (A7) from the fan housing (G1).
2. Slide grommet (B7) with slight pressure onto fuel pipe
(B5) out of fan housing (G1) while lifting off burner unit
(B) vertically upward.
A7
B7
Thermo Top Evo 9Repair
904
Fig. 903 Detailed illustration of cable routing for glow
plug
9.2.2 Installing burner unit
IMPORTANT
When changing a burner, the correct model must be
ensured! The assignment of the spare part burner must be
carried out using the spare parts list via the ID number of the
burner.
The respective burner variant must be checked prior to
installation.
Fig. 904 Petrol burner unit
Fig. 905 Diesel burner unit
1. Pre-position burner unit with grommet (B7) in fan
housing (G1). During installation, make sure that the
glow plug cable (B10) and grommet (B7) are mounted
in the guide and groove provided on the fan housing
(G1) (see Fig. 903). Press grommet (B7) into groove
provided until it completely fill out the installation
space.
2. Mount gasket (A7) on positioning pins of fan housing
(G1) with flat side facing fan housing (G1).
3. Then proceed with the installation of the heat
exchanger (W1) as described in Section 9.1.2.
B7
B5
B4
B10
open closed
Retaining disc
open closed
Retaining ring
9 Repair Thermo Top Evo
905
9.3 Glow plug/Flame monitor
Fig. 906 Burner unit with glow plug
9.3.1 Electrical test of glow plug
The cold resistance must be tested by connecting contacts 1
and 2 of the connector from the glow plug to a multimeter.
Cold resistance at 25 ± 5 °C: 0.235 to 0.355 ohms.
Short-circuit test while installed: connect contact 1 of con-
nector to fan housing.
Short-circuit resistance: ohms.
NOTE
The measurement must be carried out with a multimeter
according to the four-conductor measuring principle.
To measure the cold resistance, the glow plug must be
adjusted to room temperature.
9.3.2 Removing glow plug/flame monitor
Fig. 907 Remove retaining spring
Fig. 908 Remove cooling flag
Fig. 909 Remove glow plug
NOTE
The operation of the glow plug must be checked prior to
removal. The removal of the glow plug may entail an
increased application of force, therefore destroying the
glow plug.
Shape the cables of the new glow plug in accordance with
the cable shape of the old glow plug.
B2B8 B3
B4
B7
8
Thermo Top Evo 9Repair
906
9.3.3 Installing glow plug/flame monitor
Fig. 910 Installing glow plug
Fig. 911 Installing cooling flag
Fig. 912 Installing retaining spring
Fig. 913 Installing glow plug properly
Fig. 914 Installing glow plug
Fig. 915 Routing glow plug cable with slight bend
1. Position combustion pipe with evaporator mount hori-
zontally toward rear (see Fig. 910).
2. Slide glow plug (B4) with unbent cable (B10) as far as
possible into mounting hole of glow plug dome (B8).
IMPORTANT
Install glow plug (B4) with groove (B11, below ceramic)
toward combustion pipe (see detail Fig. 914).
3. Hold cooling flag (B3) in groove (B11) with hand on
glow plug dome (B8) (see Fig. 911 and Fig. 914).
B11
B2
B3
B8
B10
B10
B10
9 Repair Thermo Top Evo
907
4. Slide retaining spring of glow plug (B2) over cooling
flag (B3) and glow plug dome (B8) (for orientation of
retaining spring B2, see Fig. 914).
IMPORTANT
The glow plug (B4) must be installed in the glow plug dome
as far as possible.
5. Route glow plug cable (B10) as shown in Fig. 915 with
a slight bend and slide grommet (B7) onto fuel pipe
(B5).
IMPORTANT
Only use a new glow plug during installation. Uninsulated
areas of the glow plug cable must not touch and must not
come into contact with metal parts of the burner unit or the
combustion air housing (danger of short circuits).
The glow plug must not be twisted or jammed and must be
seated in the guide as far as possible during installation
(danger of breakage).
When installing the burner unit, the cable must be routed so
that it lies in the groove provided. Also see Section 9.2.2 and
Fig. 903.
9.4 Combustion-air fan unit and control
unit
The combustion-air fan unit and the control unit may not be
removed.
Combustion-air fan unit assembly spare part.
Fig. 916 Combustion-air fan unit with illustration of con-
nectors
(variant shown is equipped with the maximum
connector assignment)
SG = Control unit with connector baskets
X1 = Heater controller connector
X2 = Connector for power supply to vehicle
Contact 1: Power supply terminal 30 (Fuse)
Contact 2: Earth connection
X3 = Connector for temperature sensors
X4 = Connector for 2x circulation pump
X5 = Glow plug connector
X6 = not in use
NOTE
When replacing the combustion-air fan unit, the CO
2
set-
ting must be checked in accordance with Section 8.2.
Carry out the "Reset glow plug" routine with the Webasto
Thermo Test PC Diagnosis.
IMPORTANT
Any blind connectors present must be remounted on the
new control unit.
9.5 Heat exchanger
The heat exchanger must be replaced as a complete assem-
bly.
Fig. 917 Heat exchanger
IMPORTANT
The heat exchanger may not be dismantled into its individ-
ual parts.
NOTE
Water connection pieces with retaining plate must be
checked for damage and replaced if necessary.
The gasket and screw units for water connection pieces
must be replaced as described in section 9.7.1.
Thermo Top Evo 9Repair
908
9.6 Checking sensors
When checking the cold resistance, a distinction must be
made between the variants sensors W5 and W6 (see Section
Fig. 204 and Fig. 918). To do this, the contacts of connector
X3 of the sensors are connected to a multimeter and the
resistance is measured.
Fig. 918 Position retaining spring
while watching cable routing and position of
sensors W5 and W6
In addition, the short-circuit to earth to the metal housing,
wire crimpings and deformations of the plastic cap of the
sensors must also be checked.
NOTE
The sensors must not be removed for checking.
Sensors Contacts on
connector X3
Cold resistance at
20 ± 6 °C [ohms]
min. max.
W5 2 and 4 2.296 5.047
W6 1 and 3 30 250
Fig. 919 Sensor resistance values
W5
W6
9 Repair Thermo Top Evo
909
9.7 Water connection piece
A distinction is made between two different retaining
plates. Variant A - without locking and Variant B - with lock-
ing of connection piece on retaining plate. If water connec-
tion pieces or the retaining plate of Variant B are/is
defective, then the spare parts kit of Variant A must be
ordered and installed.
NOTE
Never mount the retaining plate and the water connection
pieces when the heater has been installed.
Fig. 920 Comparison of retaining plates without (above)
and with (below) lock
Fig. 921 Retaining plate for installing water connection
piece
9.7.1 Installing water connection piece Variant
A - without lock
1. The contact surfaces of the O-rings in the heat
exchanger must be clean and must not have any dam-
age.
2. Lay new O-rings (A5) into openings of heat exchanger.
3. Fix water connection piece (A4) in place in retaining
plate (A3) and position as assembled unit in heat
exchanger (W1). Align water connection piece for
installation case.
4. Guide screw into hole and screw on with 7.5 Nm.
IMPORTANT
When screwing on the retaining plate with the water con-
nection piece as well as the sensors, do not re-cut the thread
several times. The screw must be carefully inserted in the
existing threads and screwed in by hand.
A4
A3
A5
W1
Thermo Top Evo 10 Packing, Storage and Shipping
1001
10 Packing, Storage and Shipping
10.1 General
If the heater or its components are sent to Webasto for test-
ing or repair, it must be cleaned and packed in such a way
that it is protected against mechanical damage, soiling and
environmental influences during handling, transport and
storage.
The temperatures during transport and storage may not
drop below -40 and may not exceed 60 °C.
10.2 Storage
Position of heater:
The heater can be stored in any position. There are no re-
strictions here.
Heaters must always be stored in the delivery packaging or
in similarly suitable packaging in closed rooms!
After being removed from the delivery packaging, the heat-
ers should only make contact on the aluminium parts (for
position, see Fig. 1001). The type label and the surface of
the heater must be protected against damage with a suita-
ble surface (e.g. cardboard).
During storage the heater should be covered and must be
protected from dust, dirt and moisture.
The heater may not come into contact with chemicals or
their vapours, e.g. fuel, battery fluids or brake fluids.
No dirt, water or chemicals may enter into the openings of
the heater during storage, see above.
The fuel pipe must be protected from side impact loads
which lead to pipe deformation.
10.3 Transport
The heater can be transported in any position and must al-
ways be packed in suitable packing.
The electrical contacts and the fuel pipe must be protected
against mechanical damage.
NOTE
If an entire heater is returned, then it must be completely
drained of operating fluids. It must be ensured that no fuel
or coolant residues can escape during packing and/or ship-
ping.
The coolant connection piece and the fuel connection must
be sealed off with blind plugs.
Fig. 1001 Preferred position for Thermo Top Evo heater for storage and transport
10 Packing, Storage and Shipping Thermo Top Evo
1002
Page for notes
Ident-Nr. 1316370B • 11/12 • Errors and omissions excepted • Printed in Germany • © Webasto Thermo & Comfort SE, 2012
Webasto Thermo & Comfort SE
Postfach 1410
82199 Gilching
Germany
Visitors’address:
Friedrichshafener Str. 9
82205 Gilching
Germany
Internet: www.webasto.com
Technical Extranet: http://dealers.webasto.com
The telephone number of each country can be found
in the Webasto service center leaflet or the website of
the respective Webasto representative of your country.
