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

Troubleshooting

Function sequence and possible faults

Control unit issues
a heat demand
Yes
Fan starts
Yes
Ignition
Yes
Gas train opens
Yes
Ionisation current
builds (higher than
2 µA)
Symbol A
42
Display
No
No
After approx. 1 min
fault F9
No Fault F4
No
Fault F4
No
Fault F4
Measure
Increase set value
and ensure heat is
drawn off
Check the fan, fan
connecting cables,
power at the fan
and fan control
Check the ignition
module connec-
tion
Check the gas
train (control volt-
age 230 V) and
gas supply pres-
sure
Check the ionisa-
tion current, the
electrode adjust-
ment and the gas
line for airlocks