
78
Displayed
fault code
Const.
Weath.-
comp.
System characteris-
tics
Cause
Measures
bd
X
Control mode without
remote control
Communication er-
ror, Vitotrol remote
control
heating circuit 2
(with mixer)
Check connections, ca-
ble, coding address "A0"
in
"Heating circuit"
group and remote control
settings (see page 101).
For wireless remote con-
trols: Check connection,
place remote control unit
close to the boiler.
bE
X
Control mode without
remote control
Communication er-
ror, Vitotrol remote
control
heating circuit 3
(with mixer)
Check connections, ca-
ble, coding address "A0"
in
"Heating circuit"
group and remote control
settings (see page 101).
For wireless remote con-
trols: Check connection,
place remote control unit
close to the boiler.
bF
X
Control mode
Incorrect LON
communication
module
Replace LON communi-
cation module
C1
X
X
Control mode
Communication er-
ror, extension EA1
Check connections
C2
X
X
Control mode
Communication er-
ror, solar control
module or Vitosolic
Check solar control mod-
ule or Vitosolic
C3
X
X
Control mode
Communication er-
ror, extension AM1
Check connections
C4
X
X
Control mode
Communication er-
ror, OpenTherm
extension
Check OpenTherm exten-
sion
C5
X
X
Control mode, max.
pump speed
Communication er-
ror, internal varia-
ble speed pump
Check the setting of cod-
ing address "30" in the
"Boiler"
group (weather-
compensated control
units) or in group 2 (con-
stant temperature control
units)
C6
X
Control mode, max.
pump speed
Communication er-
ror, external varia-
ble speed heating
circuit pump,
heating circuit 2
(with mixer)
Check setting of coding
address "E5" in the
"Heating circuit"
group
C7
X
X
Control mode, max.
pump speed
Communication er-
ror, external varia-
ble speed heating
circuit pump,
heating circuit 1
(without mixer)
Check setting of coding
address "E5" in the
"Heating circuit"
group
Troubleshooting
Fault codes
(cont.)
5772 980 GB
Service