Operating instructions

Fault
code
on the
display
Const. weath.-
comp.
System char-
acteristics
Cause Measures
9b X X Control mode Cylinder
temperature
sensor lead
broken; con-
nects to the
Vitosolic at
S3
Check the sensor
at the Vitosolic.
9C X X Control mode Temperature
sensor lead
broken; con-
nects to the
Vitosolic at
S2
Check the sensor
at the Vitosolic.
9F X X Control mode Solar control
unit fault;
displayed if a
fault without
fault code
occurs at the
solar control
unit
Check the solar
control unit (see
solar control unit
service instruc-
tions).
A7 X Control mode
as per deliv-
ered condition
Faulty pro-
gramming
unit
Replace the pro-
gramming unit.
b0 X X Burner
blocked
Flue gas
temperature
sensor
shorted out
Check the flue
gas temperature
sensor (see
page 85).
b1 X X Control mode
as per deliv-
ered condition
Communica-
tion fault;
program-
ming unit (in-
ternal)
Check connec-
tions and replace
the programming
unit if required.
b4 X X Regulates as
if the outside
temperature
was 0 °C
Internal fault Replace the con-
trol unit.
Fault codes (cont.)
72
Troubleshooting
5692 672 GB