Viessmann VITOTRONIC 200 Service Instructions Manual page 59

Messages
(cont.)
Message
Code/system characteris-
tics
CB Flow temp. primary
Compressor stops.
CC Coding card
Heat pump does not
start.
CD KM BUS Vitocom
No communication via
Vitocom 100.
Cause
Min. flow temperature in
primary circuit (brine
inlet/air intake) not ach-
ieved.
Coding card cannot be
read.
Communication fault KM
BUS Vitocom 100.
Troubleshooting
Measures
■
: Check primary circuit
for throughput.
■
: Outside temperature
too low, no measures
required.
■ Check coding card:
Switch off heat pump
and check whether cod-
ing card has been inser-
ted correctly; reinsert
correctly if required.
Replace coding card if
test was unsuccessful.
■ Check controller and
sensor PCB (see
page 172); replace if
required.
Check Vitocom 100 con-
nections and connecting
cables.
Check connection aVG
KM BUS (see page 172).
A fluctuating DC voltage
between approx. 20 V and
30 V can be measured at
the terminals.
59