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Vitocrossal 300 CU3A 26 to 199 Service
5673 649 - 18
88
Troubleshooting
Fault Codes
(continued)
Fault code on display
System behavior
*1
Cause
Corrective action
BD
Control mode without remote
control
Communication error,
remote control Vitotrol
heating circuit 2
(with mixing valve)
Check connections, cable,
coding address “A0” in “Heating
circuit” group and remote control
unit setting. For wireless remote
control units: Check radio path
connections, place
remote control unit and wireless
repeater close to the boiler.
Check KM BUS connection to
wireless base station. Replace
wireless components.
BE
Control mode without remote
control
Communication error,
remote control Vitotrol
heating circuit 3
(with mixing valve)
Check connections, cable,
coding address “A0” in “Heating
circuit” group and remote control
unit setting. For wireless remote
control units: Check radio path
connections, place
remote control unit and wireless
repeater close to the boiler.
Check KM BUS connection to
wireless base station. Replace
wireless components.
BF
Control mode
Incorrect LON
communication module
Replace LON communication
module.
C1
Control mode
Communication fault
extension EA1
Check connections.
Without extension EA1, set
code “35:0”
C2
Control mode
Communication fault -
solar control unit or
Vitosolic
Check solar control or Vitosolic.
C4
Control mode
Communication fault,
Open Therm extension
Check Open Therm extension.
C7
Control mode, max. pump speed Communication
fault-variable
speed circulation
pump,heating circuit
without mixing valve,
heating circuit pump A1
Check setting of coding address
”E5”.
C8
Control mode, max. pump
speed
Communication error,
external variable speed
heating circuit pump,
heating circuit 3 (with
mixing valve)
Check setting of coding address
“E5”
CD
NOT USED
Control mode
Communication fault,
Vitocom 100 (KM-BUS)
Check connections Vitocom 100
coding address “95”
CF
Control mode
Communication fault -
LON communication
module
Replace LON communication
module.
D6
Control mode
Input DE1 reports a
fault at extension EA1
Remove fault at appliance
concerned.
D7
Control mode
Input DE2 reports a
fault at extension EA1
Remove fault at appliance
concerned.
*1
Control mode:..............Boiler/burner fully operational (fault code must be verified and reset).
Burner in fault mode:.....Boiler control requires manual reset before burner can resume operation.
Burner blocked: ...........If fault cause is corrected, burner resumes operation.