Troubleshooting; Function Sequence And Possible Faults - Viessmann Vitodens 100-W WB1B Installation And Service Instructions Manual

Troubleshooting

Function sequence and possible faults

Control unit is-
sues a heat de-
mand
Yes
Fan starts
Yes
Ignition
Yes
Gas train opens
Yes
Ionisation current
builds (higher
than 2 µA)
Symbol A
Yes
Burner in opera- No
tion
32
Display screen
No
after approx. 51 s
No
fault F9
Fault F4
No
Fault F4
No
Fault F4
No
Stops below the
set boiler water
temperature and
restarts immedi-
ately
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 con-
nection ignition
module
Check the gas
train (control vol-
tage 230 V);
check the gas
supply pressure
Check the ionisa-
tion current,
check the elec-
trode adjustment
and the gas pipe
for airlocks.
Check the flue
gas system for
tightness (flue
gas recircula-
tion), check the
gas flow pressure