Webasto Thermo Top Z Shop Manual page 22

5 Troubleshooting
5.2 Error Messages during
Functional Test with Diagnosis Tester
Thermo Test
Error Message
Control unit defective
Flame-out 1
Flame-out 2
Voltage too high
Voltage too low
Flame before combustion
operation (not applicable for
Thermo Top Z)
Overheating
Dosing pump short circuit
Dosing pump open circuit
Burner motor short circuit
Burner motor open circuit
502
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• Faulty electronics
• EOL programming error
Flame-out during operation and no flame-up after a new attempt to start
• Wrong integration in fuel system (e.g. fuel supply confused with return)
• Fuel tapping dependent on fuel level
• Pressure in fuel system too low
• Check valve in fuel system
• Leak in fuel line connections
• Degassing fuel lines (routed in environment too hot)
• Installation orientation of dosing pump
• Combustion air intake not as specified
• Exhaust system not as specified
• Burner defective
Several flame-outs during operation
• Wrong integration in fuel system (e.g. fuel supply confused with return)
• Fuel tapping dependent on fuel level
• Pressure in fuel system too low
• Check valve in fuel system
• Leak in fuel line connections
• Degassing fuel lines (routed in environment too hot)
• Installation orientation of dosing pump
• Combustion air intake not as specified
• Exhaust system not as specified
• Burner defective
• Vehicle battery charger probably defective
• Battery discharged or defective
• High transition resistance in the power supply lines (plus and minus)
• Glow plug / flame sensor defective
• Coolant level too low
• Heater has not been bled
• No circulation
• Ground short in power supply line to dosing pump
• Open line to dosing pump
• Short circuit to plus of power supply
Thermo Top Z:
• Switched line short circuit to plus of power supply
• Overload or short circuit of burner motor
Thermo Top E und C:
• Ground short in power supply line to burner motor
• Open line to burner motor
• Short circuit to plus of power supply
Fig. 502 Error Messages (Sheet 1 of 2)
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Thermo Top E and Z/C
NOTE
The following table (Fig. 502) lists possible error
messages during the functional test with the diagnosis
tester and their probable cause.
Probable Cause