Technical data

Troubleshooting Thermo 90 S / Thermo 90 ST

12.2.2. 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 during the run-on time of the

heater.

After five short signals, count the long flashes:

0x (only five short signals)

Heater lock-out or control unit defective,

Unlocking only possible by an authorised workshop

1x No start (after 2 attempts to start)

2x Flame failure

3x Undervoltage or overvoltage

4x Premature flame recognition

5x 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