Function Sequence And Possible Faults - Viessmann Vitodens 200-W Installation Instructions Manual

Function sequence and possible faults

Control unit issues
heat demand
Fan starts
Ignition
Gas train opens
Ionisation current
symbol displayed
68
Yes
No
after approx. 51 s
Fault F9
Yes
No
Fault F4
Yes
No
Fault F4
Yes
No
Fault F4
Display screen
No
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 ignition
module (control
voltage 230V
across plugs
"X2.1" and "X2.2"
Check the gas
train (control
voltage 230 V);
check the gas
supply pressure
Check the
ionisation electrode
adjustment and the
gas pipe for airlocks