Viessmann Vitodens 333 Service Instructions Manual page 74

Troubleshooting
Fault codes
(cont.)
Display Const. Weath.
fault comp.
code
b0 X X
b1 X X
b4 X X
b5 X X
b7 X X
b8 X X
bA X
bC X
bd X
74
System char- Cause
acteristics
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
Burner Flue gas
blocked temperature
sensor break
Mixer "Close" Communica-
tion fault
extension kit
for heating
circuit M2
Control mode Communica-
without remote tion fault
control Vitotrol re-
mote control,
heating cir-
cuit A1
Control mode Communica-
without remote tion fault
control Vitotrol re-
mote control,
heating cir-
cuit M2
Remedy
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
Checking the flue
gas temperature
sensor
Check the exten-
sion kit connec-
tions and
encoding; start
the extension kit
Check connec-
tions, cable/lead
and coding ad-
dress "A0"
Check connec-
tions, cable/lead
and coding ad-
dress "A0"