Viessmann VITODENS 100-W Manual page 63

Fault finding
(Fortsetzung)
Yes
Gas combina-
tion valve opens
Yes
Ionisation cur-
rent builds (hig-
her than 2 µA)
Symbol A
Yes
Burner in opera-
tion
Fault messages in the display
Fault
No
F4
Fault
No
F4
Stops below set
boiler temperatu-
re and restarts
Faults are indicated by a flashing fault
code with fault symbol U and the
reset key is illuminated.
For fault code explanations see the
following table.
Störungsbehebung
Check the gas
train (control vol-
tage 230 V) and
gas supply press-
ure
Check the ionisa-
tion current, check
the electrode ad-
justment and the
gas pipe for air-
locks.
Check flue gas
system for sound-
ness (flue gas re-
circulation), check
gas flow pressure
63