Viessmann VITODENS 333-F WS3A Service Instructions Manual page 76

Troubleshooting
Fault codes
(cont.)
Fault Const. Weath.-
code comp.
on the
display
9C X X
9F X X
A7 X
b0 X X
b1 X X
b4 X X
b5 X X
b7 X X
76
System char- Cause
acteristics
Control mode Temperature
sensor lead
broken; con-
nects to the
Vitosolic at
S2
Control mode Solar control
unit fault;
displayed if a
fault without
fault code
occurs at the
solar control
unit
Control mode Faulty pro-
as per the de- gramming
livered condi- unit
tion
Burner Flue gas
blocked temperature
sensor
shorted out
Control mode Communica-
as per the de- tion error,
livered condi- program-
tion ming unit
Regulates as Internal fault
if the outside
temperature
was 0 °C
Control mode Internal fault
as per the de-
livered condi-
tion
Burner Boiler coding
blocked card fault
Measures
Check the sensor
at the Vitosolic.
Check the solar
control unit (see
solar control unit
service instruc-
tions).
Replace program-
ming unit
Check the flue
gas temperature
sensor
Check connec-
tions and replace
the programming
unit, if required
Replace the con-
trol unit
Replace the con-
trol unit
Plug in boiler cod-
ing card or re-
place, if faulty