Installation manual

www.webasto.us 35 Webasto Thermo & Comfort N.A., Inc.
Thermo Pro 90 Troubleshooting
14. Troubleshooting
14.1 General Information
The control unit continuously monitors the heater operation. The control unit identifies errors on individual heater
components and faults during operation. Should the control unit experience component errors and operational faults,
the heater will be shut down.
14.2 Heater Interlock
Fuel is supplied for a max. of 240 seconds if the flame does not start.
Fuel is supplied for a max. of 240 seconds if the flame goes out during operation.
The fuel supply is shut off if the system overheats (temperature limiter is tripped). If the system overheats the
temperature limiter will reset itself after a cool down period.
If the under-voltage protection switches the system off for longer than 20 seconds, the fuel supply is interrupted and
the heater switches OFF.
NOTE:
The heater does not automatically switch back ON. The heater will need to be switched OFF and back ON to re-start
after a fault.
14.2.1 Interlock Reset Procedure
Continue with this procedure if:
•there is NO heater function
• fault indicator light continuously flashes
1. With switch in the “ON” position, remove power source (Fuse, B+, B-)
2. Turn switch “OFF”
3. Reinstall power source (Fuse, B+, B-)
4. Reset procedure is now complete.
5. Validate heater operation. If fault codes persist refer to section 14.3 and repair as necessary.
14.3 Diagnostic after a Fault Lock-out for the Thermo Pro 90
Check the fuses and plug connectors.
14.3.1 Version with switch
If the system is operated with a switch, the nature of the fault is indicated by a flashing code on an indicator light
(toggle of switch) during the run-on time of the heater.
After five short signals, count the long flashes:
1x No start (after 2 attempts to start)
2x Flame failure
3x Under-voltage or over-voltage
4x Premature flame recognition
Thermo Pro 90
12 Volt 10.V – 0.5V
24 Volt 21V – 1V