Function Sequence And Possible Faults; Fault Display - Viessmann VITODENS 111-W Installation And Service Instructions Manual

Function sequence and possible faults

Control unit issues a heat
demand
Yes
Fan starts
Yes
Ignition
Yes
Gas train opens
Yes
Ionisation current builds
(above 2 A)
µ
Symbol
A
Yes
Burner in operation

Fault display

Fig. 31
Display
No
No
After approx. 1 min, fault
F9
No
Fault F4
No Fault F4
No Fault F4
No Shuts down below the set
boiler water temperature
and restarts immediately
In case of a fault, the display will show
code.
If flashes and "R" appears, the burner is locked.
See page 41.
For an explanation of the fault codes, see the following
table.
Troubleshooting
Action
Increase set value and
ensure heat is drawn off
Check the fan, fan con-
necting cables, power at
the fan and fan control
Check the ignition module
connection
Check the gas train
(230 V control voltage)
and gas supply pressure
Check electrode adjust-
ment and gas line for air-
locks.
Check the flue system for
tightness (flue gas recir-
culation); check the gas
flow pressure
and the fault
39