Viessmann VITOTRONIC 300 GW2 Installation And Service Instructions Manual page 84

Troubleshooting
Diagnosis
(continued)
Faults with fault display on the programming unit (continued)
Fault code
Behaviour of system
in display
Boiler cools down
c1
Controlled operation
c2
Controlled operation
c4
Boiler cools down
c8
Boiler cools down
c9
Boiler cools down
ca
Boiler cools down
cb
Controlled operation
cd
Controlled operation
cE e
Controlled operation
cf
Boiler cools down
d1
Boiler cools down
d4
Controlled operation
d6
Controlled operation
d7
Controlled operation
d8
Controlled operation without
da
influence of room
temperature
Controlled operation without
db
influence of room
temperature
84
Cause of fault
External safety equipment
Open circuit
KM-BUS to solar control
Fault
Input module 0-10V
Fault
Low water indicator
Fault
Maximum pressure limiter
Fault
Minimum pressure limiter or
maximum pressure limiter 2
Fault
Additional fixed high limit
Communication fault
Vitocom 300
Communication fault
Plug-in adaptor for external safety
equipment
Fault
LON communication module
Burner fault
Fixed high limit has operated
Fault at DE1 in the plug-in
adaptor for external safety equipment
Fault at DE2 in the plug-in
adaptor for external safety equipment
Fault at DE3 in the plug-in
adaptor for external safety equipment
Short circuit
Room temperature sensor, system
circuit A1
Short circuit
Room temperature sensor,
mixing valve circuit M2
Action
Check connection of plug
aBÖ
Check external safety
equipment (see page 40)
Check KM-BUS connection and
solar control. Without solar
control, set coding address
"54: 0"
Check all connections, cables etc.
Replace function expansion
module; without expansion
module set coding address
"9d: 0"
Check water level of system,
reset low water indicator
Check system pressure, reset
maximum pressure limiter
Check system pressure, reset
minimum or maximum pressure
limiter
Check system pressure, reset
fixed high limit, reset flue gas
damper
Check connections and
Vitocom 300
Check plug-in adaptor for
external safety equipment
Replace communication module
Check burner
Check fixed high limit
Check connection at inputs DE1
to DE3
Check room temperature sensor
(see page 112)
Check room temperature sensor
(see page 112)