Viessmann VITODENS 222-F Installation And Service Instructions Manual page 99

Fault codes
(cont.)
Fault Const. Weath.-
code on comp.
the dis-
play
F8 X X
F9 X X
FA X X
FC X X
Fd X X
System char- Cause
acteristics
Burner in a fault The gas valve
state closes too
late
Burner in a fault Fan speed
state too low during
the burner
start
Burner in a fault Fan not at
state standstill
Burner in a fault Gas train
state faulty or faulty
modulation
valve control;
or flue gas
path blocked
Burner in a fault Burner con-
state trol unit fault
Troubleshooting
Measures
Check the gas
train. Check both
control paths.
Press reset button
R.
Check the fan,
check the fan con-
necting cables and
power supply;
check the fan con-
trol.
Press reset button
R.
Check the fan, fan
connecting cables
and fan control.
Press reset button
R.
Check the gas
train. Check flue
gas system.
Press reset button
R.
Check ignition
electrodes and
connecting cables.
Check whether a
strong interference
(EMC) field exists
near the equip-
ment.
Press reset button
R.
Replace control
unit if the fault per-
sists.
99