Viessmann VITODENS 200-W WB2B Series Start-Up/Service Instructions page 57

Diagnostics
(continued)
Fault codes
(continued)
Fault code on display
bA
bC
bd
bE
bF
C2
C5
C7
Cd
CE
CF
dA
db
dd
dE
E4
E5
*1
System behavior
Mixing valve regulates to a
supply temperature of 20°C
Control mode without remote
control
Control mode without remote
control
Control mode
Control mode
Control mode
Control mode, max. pump
speed
(Not used)
Control mode, max. pump
speed
(Not used)
Control mode
(Not used)
Control mode
Control mode
Control mode without room
influence
Control mode without room
influence
Control mode without room
influence
Control mode without room
influence
Burner blocked
Burner blocked
Cause
Communication fault -
accessory kit for heating
circuit with mixing valve
Communication fault -
Vitotrol remote control,
heating circuit without
mixing valve, A1
Communication fault,
Vitotrol remote control,
heating circuit with mixing
valve, M2
Vitotrol remote control
incorrectly programmed
Incorrect LON communication
module
Communication fault,
solar control unit
Communication fault, variable
speed circulation pump,
heating circuit connection set
Communication fault,variable
speed circulation pump,heat-
ing circuit without mixing valve
Communication fault,
Vitocom 100 (KM-BUS)
Communication fault-power/
pump module KM-BUS connection
Communication fault,
LON communication module
Room temperature sensor,
heating circuit without
mixing valve (A1) shorted out
Room temperature sensor,
heating circuit with mixing
valve (M2) shorted out
Room temperature sensor,
heating circuit without
mixing valve (A1) cable
broken
Room temperature sensor,
heating circuit with mixing
valve (M2) cable broken
Fault, supply voltage 24V
Internal fault
Troubleshooting
Corrective action
Check accessory kit
connections and coding.
Turn on the accessory kit
Check connections, cable,
coding address "A0" and
remote control DIP switches
(see page 66)
Check connections, cable,
coding address "A0" and
remote control DIP switches
(see page 66)
Check remote control DIP
switches (see page 66)
Replace LON communication
module
Check connections and
coding address "54"
Check setting of coding
address "30" Set to "0"
30:"0"
Check setting of coding
address "E5"
Check coding address "95"
and set value to 95:0
Check connections and set-
ting of coding address"2E"
Replace LON communication
module
Check the room temperature
sensor, heating circuit
without mixing valve (A1)
Check the room temperature
sensor, heating circuit with
mixing valve (M2)
Check the room temperature
sensor, heating circuit A1 and
the remote control DIP switch
settings (see page 66)
Check the room temperature
sensor, heating circuit M2
and the remote control DIP
switch settings (see page 66)
Replace the control unit
Check the ionization
electrode and cables. Check
tightness of flue gas system.
Press " RESET"
57