Viessmann FB2A Installation And Service Instructions For Contractors page 92

Troubleshooting
Fault codes
(cont.)
Fault code System characteris-
on the dis- tics
play
F9 Burner in a fault
state
FA Burner in a fault
state
FC Burner in a fault
state
Fd Burner in a fault
state
FE Burner blocked or in a
fault state
FF Burner blocked or in a
fault state
92
Cause
Fan speed too low
during the burner
start
Fan not at stand-
still
Gas train faulty or
faulty modulation
valve control; or
flue gas path
blocked
Burner control unit
fault
Boiler coding card
or main PCB faulty
Internal fault or
reset button R
blocked
Measures
Check the fan, check the
fan connecting cables and
power supply; check the
fan control.
Press reset button R.
Check the fan, fan con-
necting 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 persists.
Press reset button R.
Replace boiler coding
card or control unit if the
fault persists.
Start the equipment
again. Replace the control
unit if the equipment will
not restart.