Viessmann Vitodens 222-F Installation And Service Instructions For Contractors page 90

Troubleshooting
Fault codes
(cont.)
Fault code dis- System characteristics
played
0F Control mode
20 Regulates without flow tem-
perature sensor (low loss
header)
21 Control mode
Display fault in energy cock-
pit
22 Control mode
Display fault in energy cock-
pit
23 Control mode
Display fault in energy cock-
pit
24 Control mode
Display fault in energy cock-
pit
25 Control mode
Display fault in energy cock-
pit
26 Control mode
Display fault in energy cock-
pit
27 Control mode
Display fault in energy cock-
pit
28 Regulates without flow tem-
perature sensor (low loss
header)
30 Burner blocked
38 Burner blocked
40 Mixer being closed
44 Mixer being closed
48 Mixer being closed
49 Mixer being closed
4C Mixer being closed
90
Cause
Maintenance
"0F" is only displayed in
the fault history
Short circuit, system flow
temperature sensor
Sensor outside tolerance
range
Sensor outside tolerance
range
Incorrect commissioning
DHW circulation pump not
working
Transfer pump not work-
ing
DHW circulation pump
and transfer pump not
working
Incorrect commissioning
Lead break, system flow
temperature sensor
Short circuit, boiler water
temperature sensor
Lead break, boiler water
temperature sensor
Short circuit, flow temper-
ature sensor, heating cir-
cuit 2 (with mixer)
Short circuit, flow temper-
ature sensor, heating cir-
cuit 3 (with mixer)
Lead break, flow tempera-
ture sensor, heating circuit
2 (with mixer)
Incorrect assignment of
extension for mixer, heat-
ing circuit 2
Lead break, flow tempera-
ture sensor, heating circuit
3 (with mixer)
Measures
Service required
Note
After servicing, set code "24:0".
Check low loss header sensor (see
page 104)
Check sensor on DHW cylinder
and collectors
Check sensor on DHW cylinder
and collectors
Determine solar circuit flow rate (if
installed) and enter value estab-
lished
Check setting of parameter 39
("General" group). If required, car-
ry out an actuator test.
Check setting of parameter 20
("Solar" group). If required, carry
out an actuator test.
Check settings of parameter 20
("Solar" group) and parameter 39
("General" group). If required, car-
ry out an actuator test.
Determine solar circuit flow rate (if
installed) and enter value estab-
lished
Check low loss header sensor (see
page 104)
If no low loss header sensor is
connected, set parameter 52:0.
Check boiler water temperature
sensor (see page 104)
Check boiler water temperature
sensor (see page 104)
Check flow temperature sensor
(see page 109)
Check flow temperature sensor
(see page 109)
Check flow temperature sensor
(see page 109)
Check and adjust rotary selector
S1 (see page 109)
Check flow temperature sensor
(see page 109)