Viessmann FB2B Installation And Service Instructions Manual page 107

Fault codes
(cont.)
Displayed System characteris-
fault code tics
b8 Burner blocked
bA Mixer regulates to 20
°C flow temperature.
bb Mixer regulates to 20
°C flow temperature.
bC Control mode without
remote control
bd Control mode without
remote control
bE Control mode without
remote control
bF Control mode
C1 Control mode
C2 Control mode
C3 Control mode
Cause Measures
Lead break, flue Check the flue gas tem-
gas temperature perature sensor
sensor
Communication Check the extension kit
error, extension kit connections and coding
for heating circuit 2
(with mixer)
Communication Check the extension kit
error, extension kit connections and coding
for heating circuit 3
(with mixer)
Communication Check connections, lead,
error, remote con- coding address "A0" and
trol Vitotrol heating remote control settings
circuit 1 (without (see page 143).
mixer)
Communication Check connections, lead,
error, remote con- coding address "A0" and
trol Vitotrol heating remote control settings
circuit 2 (with (see page 143).
mixer)
Communication Check connections, lead,
error, remote con- coding address "A0" and
trol Vitotrol heating remote control settings
circuit 3 (with (see page 143).
mixer)
Incorrect LON Replace the LON commu-
communication nication module
module
Communication Check electrical connec-
error extension tions
EA1
Solar control mod- Check solar control mod-
ule communication ule
fault
Extension AM1 Check electrical connec-
communication tions
error
Troubleshooting
107