Viessmann VITODENS 222-F Service Instructions Manual page 70

Troubleshooting
Fault Codes
(continued)
Fault code on display
40
44
48
4C
50
51
58
59
A3
A7
A8
A9
*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.
70
System behavior*1
Mixing valve closes
Mixing valve closes
Mixing valve closes
Mixing valve closes
No DHW heating
No DHW heating
No DHW heating
No DHW heating
Burner blocked
Control mode (stays in
factory default setting)
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.
Vitodens 222-F B2TA 19 and 35 Service
Cause
Heating circuit 2 with
mixing valve supply
short circuit on
temperature sensor
Short circuit, supply
temperature sensor,
heating circuit 3
(with mixing valve)
Heating circuit 2 with
mixing valve supply
temperature sensor
cable broken
Supply temperature
sensor cable broken
circuit 3 (with mixing
valve)
Short circuit on DHW
tank temperature sensor
Short circuit on outlet
temperature sensor
Tank temperature
sensor cable broken
Outlet temperature
sensor cable broken
Flue gas temperature
sensor not properly
positioned
Faulty programming
unit
Air lock in the internal
circulation pump or
minimum flow rate not
achieved
Internal circulation
pump blocked
Corrective action
Check the supply
temperature sensor
(see page 79).
Check supply temperature
sensor (see page 79).
Check the supply temperature
sensor (see page 79).
Check supply temperature
sensor (see page 79).
Check the DHW sensor
(see page 78).
Check the sensor (see page 78)
Check the sensor (see page 78).
Check the sensor (see page 78)
Properly install flue gas
temperature sensor.
Replace the programming unit.
Vent the system if the fault
message continues to be
displayed
Check the circulation pump