Installation manual

Troubleshooting
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3. Troubleshooting
Fault lock-out
• Fuel is supplied for max. 240 seconds if the flame does not start to burn.
• Fuel is supplied for max. 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 button
on the temperature limiter must be reset.
Once the cause of the fault has been eliminated, the fault lock-out is cancelled by switching the heater off and on again.
If the under voltage guard switches off the system for longer than 20 seconds, the fuel supply is interrupted.
Version with Light
If the system is operated with a light, the nature of the fault is indicated by a flashing code on an indicator light during the
cool down time of the heater. After five short signals, count the long flashes:
Thermo 90 ST
12 V 10.5V – 0.5V
24 V 21V – 1V
1x No start (after 2 attempts to start)
2x Flame failure
3x Under voltage or over voltage
4x Premature flame recognition
4x Flame sensor interrupt or
flame sensor short-circuit
6x Temperature sensor interrupt or
temperature sensor short-circuit
7x Metering pump interrupt or
metering pump short-circuit
8x Blower motor interrupt or
blower motor short-circuit or
blower motor incorrect speed
9x Glow plug interrupt or
glow plug short-circuit
10x Overheating
11x Circulating pump interrupt or
circulating pump short-circuit