Viessmann Vitodens 222-F Installation And Service Instructions For Contractors page 94

Troubleshooting
Fault codes
(cont.)
Fault code dis- System characteristics
played
B7 Burner blocked
B8 Burner in a fault state
BA Mixer regulates to 20 °C flow
temperature.
BB Mixer regulates to 20 °C flow
temperature.
BC Control mode without remote
control
BD Control mode without remote
control
BE Control mode without remote
control
BF Control mode
C1 Control mode
C3 Control mode
C4 Control mode
C5 Control mode, max. pump
speed
CD Control mode
CF Control mode
D3 Burner in a fault state or
blocked
D4 Control mode
Burner is operating with a
limited modulation range.
D5 Burner in a fault state
94
Cause
Boiler coding card fault
Lead break, flue gas tem-
perature sensor
Communication error, ex-
tension kit for heating cir-
cuit 2 (with mixer)
Communication error, ex-
tension kit for heating cir-
cuit 3 (with mixer)
Communication error,
Vitotrol remote control,
heating circuit 1 (without
mixer)
Communication error,
Vitotrol remote control,
heating circuit 2 (with mix-
er)
Communication error,
Vitotrol remote control,
heating circuit 3 (with mix-
er)
Incorrect LON communi-
cation module
Communication error, EA1
extension
Communication error,
AM1 extension
Communication error,
OpenTherm extension
Communication error, in-
ternal variable speed
pump
Communication error,
Vitocom 100 (KM-BUS)
Communication error,
communication module
Communication error, fan
unit.
No air flow detected in fan
unit.
Fan blocked
Measures
Plug in boiler coding card or re-
place if faulty
Check flue gas temperature sensor
and connecting lead.
Check extension kit connections
and assignment.
Check extension kit connections
and assignment.
Check connections, lead, parame-
ter "A0" and remote control set-
tings (see page 141).
For wireless remote control units:
check connection; place remote
control close to the boiler.
Check connections, lead, parame-
ter "A0" and remote control set-
tings (see page 141).
For wireless remote control units:
check connection; place remote
control close to the boiler.
Check connections, lead, parame-
ter "A0" and remote control set-
tings (see page 141).
For wireless remote control units:
check connection; place remote
control close to the boiler.
Replace LON communication mod-
ule
Check connections
Check connections
Check OpenTherm extension
Check setting of parameter "30"
Check connections, Vitocom 100
and parameter "95"
Replace communication module
Check the connecting cable to the
fan unit. Press reset button R.
If the fault recurs, replace the fan
unit.
Check the mass flow sensor at the
fan unit. Check the flue system for
flue gas back pressure.
Press reset button R. Check fan
impeller movement. If necessary,
replace fan.