Viessmann Vitotronic 300 Installation And Service Instructions Manual page 45

Vitotronic 300, GW5B Installation and Service
Fault Codes
(continued)
Displayed System characteristics
fault code
C2 Control mode
C8 Boiler cools down
C9 Boiler cools down
CA Boiler cools down
CB Boiler cools down
CD Control mode
CE Control mode
CF Control mode
No communication
via LON.
D1 Boiler cools down
D2 Control mode
D3 Control mode
D4 Boiler cools down
D6 Control mode
Cause
Lead break, KM BUS to solar
control module or Vitosolic.
Fault, low water indicator at
"X7" of plug-in adaptor 1 for
external safety equipment
Fault, maximum pressure limiter
at "X3" of plug-in adaptor 1 for
external safety equipment
Fault, minimum or maximum
pressure limiter 2 at "X2" of
plug-in adaptor 1 for external
safety equipment.
Additional high limit safety
cut-out fault
Communication fault, Vitocom
100, type GSM2.
Communication fault, plug-in
adaptor 1 for external safety
equipment.
Communication fault, control unit
LON communication module.
Burner fault
Communication fault, plug-in
adaptor 2 for external safety
equipment.
Communication fault, extension
EA1.
The fuse F2 has blown.
Input DE1 at extension EA1
reports a fault.
Troubleshooting
Measures
Check KM BUS cable and
appliance.
Without solar control unit:
Set code "54:0" in the "General"
group.
Check the water level of
the system; reset low water
indicator.
Check the system pressure and
reset the maximum pressure
limiter.
Check system pressure and reset
minimum or maximum pressure
limiter 2.
Check the system temperature
and reset the high limit safety
cut-out.
Check connections and Vitocom
100 (see separate installation
and service instructions).
Without Vitocom 100: Set code
"95:0" in the "General" group.
Check plug-in adaptor (see page
129). Without plug-in adaptor:
Set code "30:0" in the "General"
group.
Check LON communication
module and replace if required.
If no LON communication module
is installed, set code "76:0" in
the "General" group.
Check the burner.
Check plug-in adaptor (see page
131). Without plug-in adaptor:
Set code "31:0" in the "General"
group.
Check connections (see page
137). Without extension EA1:
Set code "5B:0" in the "General"
group.
Check fuse F2.
Remove fault at appliance
concerned.
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