Viessmann VITODENS 343-F WS4A Installation And Service Instructions Manual page 95

Fault codes
(cont.)
Fault code System character-
on the dis- istics
play
b4 Regulates as if the
outside temperature
was 0 °C
b5 Control mode as per
delivered condition
b7 Burner blocked.
bA Mixer M2 continues
to regulate.
bC Control mode with-
out remote control
bd Control mode with-
out remote control
bE Control mode
bF Control mode
C2 Control mode
Cd Control mode
CE Control mode
CF Control mode
Cause Measures
Internal fault Replace the control unit.
Internal fault Replace the control unit.
Boiler coding card Plug in boiler coding
missing, faulty or card or replace it, if
incorrect boiler faulty.
coding card
Communication Check the extension kit
fault, extension connections and coding.
kit for mixer cir- Start the extension kit.
cuit M2
Communication Check connections,
fault Vitotrol re- cable, coding address
mote control, "A0" and the remote
heating circuit A1 control DIP switches.
Communication Check connections,
fault, Vitotrol re- cable, coding address
mote control, "A0" and the remote
heating circuit M2 control DIP switches.
Vitotrol remote Check remote control
control incorrectly DIP switch setting (see
programmed page 126)
Incorrect LON Replace the LON com-
communication munication module.
module
Communication Check connections and
fault, solar control coding address "54".
unit
Communication Check connections and
fault Vitocom 100 the Vitocom 100.
(KM BUS)
Communication Check connections and
fault - ext. exten- settings of coding ad-
sion dress "2E".
Communication Replace the LON com-
fault, LON com- munication module.
munication mod-
ule
Troubleshooting
95