Viessmann Vitoplus 300 - Page 70

Display fault
code
System char-
acteristics
Cause Measures
9F Control mode Solar control unit fault
message
See solar control
unit service in-
structions
A7 Control mode
as per the de-
livered condi-
tion
Faulty programming unit Replace program-
ming unit
b0 Burner
blocked
Flue gas temperature
sensor shorted out
Check the flue
gas temperature
sensor (see
page 79)
b8 Flue gas temperature
sensor break
b1 Control mode
as per the de-
livered condi-
tion
Communication error pro-
gramming unit (internal)
Check connec-
tions and replace
programming unit,
if required
b4 Regulates as if
the outside
temperature
was 0 °C
Internal fault analog con-
verter
Replace the con-
trol unit
b5 Control mode
as per the de-
livered condi-
tion
Internal fault Replace the con-
trol unit
b7 Burner
blocked
Boiler coding card miss-
ing, faulty or incorrect
boiler coding card
Plug in boiler cod-
ing card or re-
place, if faulty
bA Mixer M2 regu-
lates in accor-
dance with the
last trans-
mitted set
value
Communication fault –
extension kit for heating
circuit with mixer M2
Check the exten-
sion kit connec-
tions and coding.
Start the exten-
sion kit.
bC Control mode
without remote
control
Communication fault –
Vitotrol remote control,
heating circuit A1
Check connec-
tions, cable, cod-
ing address "A0"
and the remote
control DIP
switches
Fault codes (cont.)
70
Troubleshooting
5692 536 GB