Viessmann Vitodens 200-W WB2B 80 Start-Up/Service Instructions page 56

Troubleshooting
Diagnostics
(continued)
Fault codes (continued)
Fault code on display
40
48
50
58
92
93
94
9A
9b
9C
9F
A7
b0
b1
b4
b5
b7
b8
56
*1
System behavior
Mixing valve closes
Mixing valve closes
No DHW heating
No DHW heating
Control mode
Control mode
Control mode
Control mode
Control mode
Control mode
Control mode
Control mode (stays in
factory default setting)
Burner blocked
Control mode (stays in
factory default setting)
Regulates as if the outdoor
temperature was 0°C
Control mode
(factory default setting)
Burner blocked
Burner blocked
Cause
Heating circuit with mixing
valve supply temperature
sensor shorted out
Heating circuit with mixing
valve supply temperature
sensor cable broken
Tank temperature
sensor shorted out
Tank temperature sensor
cable broken
Collector temperature sensor
shorted out; connects to the
Vitosolic at S1
Collector temperature sensor
shorted out; connects to the
Vitosolic at S3
Collector temperature sensor
shorted out; connects to the
Vitosolic at S2
Collector temperature sensor
cable broken; connects to the
Vitosolic at S1
Tank temperature sensor
cable broken; connects to the
Vitosolic at S3
Tank temperature sensor
cable broken; connects to the
Vitosolic at S2
Solar control unit fault;
displayed if a fault without
fault code occurs at the solar
control unit
Faulty programming unit
Flue gas temperature sensor
shorted out
Communication fault;
programming unit (internal)
Internal fault
Internal fault
Boiler coding card missing,
faulty or incorrect boiler
coding card
Flue gas temperature sensor
cable broken
Corrective action
Check the supply
temperature sensor
(see page 60).
Check the supply
temperature sensor
(see page 60).
Check the sensor
(see page 60).
Check the sensor
(see page 60).
Check the sensor at the
Vitosolic solar control.
Check the sensor at the
Vitosolic solar control.
Check the sensor at the
Vitosolic solar control.
Check the sensor at the
Vitosolic solar control.
Check the sensor at the
Vitosolic solar control.
Check the sensor at the
Vitosolic solar control.
Check the solar control unit
(see solar control service
instructions).
Replace the programming
unit.
Check flue gas temperature
sensor (see page 61).
Check connections and
replace programming unit if
required.
Replace the control unit.
Replace the control unit.
Plug in boiler coding card or
replace if faulty.
Check flue gas temperature
sensor (see page 61).