Viessmann Vitotronic 200 KW2 Installation And Service Instructions Manual page 39

Faults which are displayed at the programming unit
Fault
System
code
characteristics
Control mode
9f
Only solar control
unit fault codes will
be displayed
Control mode
b0
b1
Emissions test mode
b4
Control mode
b5
Constant mode
b6
The boiler is
b7
regulated by the
control thermostat
Control mode
b8
b9
Cause
Fault
Solar control unit;
displayed if a fault
without fault code
occurs at the solar
control unit
Short circuit
Flue gas temperature
sensor
Communication fault
Programming unit
Internal fault
Internal fault
Invalid hardware
recognised
Boiler coding card
fault
Lead broken
Flue gas temperature
sensor
Internal fault
Troubleshooting
(cont.)
Remedy
Check solar control
unit
Check flue gas
temperature sensor
(see page 62)
Check connections
and replace
programming unit, if
necessary
Check supplementary
PCB
Check supplementary
PCB
Check main PCB
Plug in boiler coding
card or replace, if
faulty
Check flue gas
temperature sensor
(see page 62).
Without flue gas
temperature sensor:
Set code 1F : 0
Acknowledge fault,
repeat data input
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