
79
Displayed
fault code
Const.
Weath.-
comp.
System characteris-
tics
Cause
Measures
C8
X
Control mode, max.
pump speed
Communication er-
ror, external varia-
ble speed heating
circuit pump,
heating circuit 3
(with mixer)
Check setting of coding
address "E5" in the
"Heating circuit"
group
Cd
X
X
Control mode
Communication er-
ror Vitocom 100,
type GSM (KM
BUS)
Check Vitocom 100,
type GSM connections,
and coding address "95"
in the
"General"
group
(weather-compensated
control units) or in
Group 1 (constant tem-
perature control units)
CF
X
Control mode
Communication er-
ror, LON communi-
cation module
Replace LON communi-
cation module
d6
X
X
Control mode
Input DE1 at exten-
sion EA1 reports a
fault
Remove fault at relevant
appliance
d7
X
X
Control mode
Input DE2 at exten-
sion EA1 reports a
fault
Remove fault at relevant
appliance
d8
X
X
Control mode
Input DE3 fault at
extension EA1
Remove fault at relevant
appliance
dA
X
Control mode without
room influence
Short circuit, room
temperature sen-
sor
heating circuit 1
(without mixer)
Check room temperature
sensor heating circuit 1
db
X
Control mode without
room influence
Short circuit, room
temperature sen-
sor
heating circuit 2
(with mixer)
Check room temperature
sensor heating circuit 2
dC
X
Control mode without
room influence
Short circuit, room
temperature sen-
sor
heating circuit 3
(with mixer)
Check room temperature
sensor heating circuit 3
dd
X
Control mode without
room influence
Lead break, room
temperature sen-
sor
heating circuit 1
(without mixer)
Check room temperature
sensor heating circuit 1
and remote control set-
tings (see page 101)
dE
X
Control mode without
room influence
Lead break, room
temperature sen-
sor
heating circuit 2
(with mixer)
Check room temperature
sensor heating circuit 2
and remote control set-
tings (see page 101)
Troubleshooting
Fault codes
(cont.)
5772 980 GB
Service