Viessmann Vitodens 300 Service Instructions Manual page 76

Troubleshooting
Checking and acknowledging faults
Constant temperature control units
Displayed Const.
fault code
0F X
10 X
18 X
20 X
28 X
76
Note
The fault can be acknowledged
with d. The fault message in the dis-
play will be hidden, but the red fault
indicator U continues to flash. A new
fault message will be displayed if an
acknowledged fault is not removed by
the following morning.
Calling up acknowledged fault mes-
sages
Press d for approx. 2 seconds;
select the acknowledged fault with a
or b.
Weat- System
her- character-
comp. istics
X Control
mode
X Controls
according
to 0 °C out-
side tem-
perature
X
X Controls
without
flow tem-
perature
sensor
(low loss
header)
X
(cont.)
Cause Remedy
Maintenance Carry out
maintenance.
Set code 24:0
after mainte-
nance
Outside tempera- Check the
ture sensor shorted outside tem-
out perature sen-
sor (see
page 85)
Outside tempera-
ture sensor lead
break
System flow tem- Check the
perature sensor low loss
shorted out header sen-
sor (see
page 87)
System flow tem-
perature sensor
lead break