Viessmann VITODENS 222-F Service Instructions Manual page 71

Vitodens 222-F B2TB 19 and 35 Service
Fault Codes
(continued)
Fault code Detailed fault
on display code*2
A3 -
A7 -
B0 141
A8 -
A9 -
B1 -
B5 -
B7 -
B8 141
BA -
*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.
*2 Detailed fault code coding address 38:xx (if available).
System behavior*1
Burner blocked
Control mode (stays in
factory default setting)
Burner blocked
Burner blocked. The venting
program is started
automatically
(see page 14)
The burner operates at its
lower output if a heating
circuit with mixing valve is
connected. The burner is
blocked if only one heating
circuit without mixing valve
is connected.
Control mode (stays in
factory default setting)
Control mode
(factory default setting)
Burner blocked
Burner blocked
Mixing valve regulates to
a flow temperature of
68°F (20°C)
Cause
Flue gas temperature
sensor not properly
positioned
Faulty programming
unit
Flue gas temperature
sensor shorted out
Air lock in the internal
circulation pump or
minimum flow rate not
achieved
Internal circulation
pump blocked
Communication fault;
programming unit
(internal)
Internal fault
Boiler coding card
missing, faulty or
incorrect boiler coding
card
Flue gas temperature
sensor cable broken
Communication fault -
accessory kit for
heating circuit 2 with
mixing valve
Troubleshooting
Corrective action
Properly install flue gas
temperature sensor.
Replace the programming unit.
Check flue gas temperature
sensor (see page 80).
Vent the
system if the
fault message
continues to be
displayed
Check the circulation pump
Check connections and
replace programming unit
if required.
Replace the control unit.
Plug in boiler coding card or
replace if faulty.
Check flue gas temperature
sensor (see page 80).
Check extension kit connections
and code.
71