Operating instructions

60
Message
System characteristics Cause Measures
CB Primary temperature
Heat pump stops Min. primary flow tem-
perature (brine inlet) not
achieved
■ Primary circuit flow tem-
perature too low, no
measures required
CC Coding card
The coding card cannot
be read
■ Check coding card and
replace if required.
■ Check controller and
sensor PCB and
replace, if required.
CD KM BUS Vitocom
Communication error -
KM BUS Vitocom 100
Check Vitocom 100 con-
nections and connecting
cables.
Check connections at the
controller and sensor PCB
aVG
check KM BUS. A
fluctuating DC voltage
between approx. 20 V and
30 V can be measured at
the terminals.
CE KM BUS ext. extension
Communication error -
KM BUS external exten-
sion H1
Check external exten-
sion H1 connections and
connecting cables.
Check connections at the
controller and sensor PCB
aVG
check KM BUS. A
fluctuating DC voltage
between approx. 20 V and
30 V can be measured at
the terminals.
CF Communication module
Communication error -
LON module in control
unit
Check LON communica-
tion module and replace if
required.
Troubleshooting
Messages
(cont.)
5441 603 GB