Troubleshooting; Function Sequence And Possible Faults - Viessmann Vitodens 100-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
32
Display screen
no
no
after approx. 51 s
fault F9
no
Fault F4
no
Fault F4
no
Fault F4
Measures
Increase set value
and ensure heat is
drawn off
Check the fan, fan
connecting cables,
power at the fan
and fan control
Check the connec-
tion ignition mod-
ule
Check the gas
train (control volt-
age 230 V); check
the gas supply
pressure
Check the ionisa-
tion current, check
the electrode
adjustment and
the gas pipe for air-
locks.