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Vitocrossal 300 CU3A 26 to 199 Service
5673 649 - 18
92
Troubleshooting
Fault Codes
(continued)
Fault code on display
System behavior
*1
Cause
Corrective action
F8
Burner in fault mode
Gas valve closes too
late
Check the gas valve.
Check both control wiring/
connections.
Press reset button
R
.
F9
Burner in fault mode
Fan speed too low
during burner start
Check the fan, the fan cables
and power supply. Check the
fan control.
Press reset button
R
.
FA
Burner in fault mode
Fan not at standstill
Check the fan, the fan
connecting cables and fan
control. Check the fan control.
Press reset button
R
.
FC
Burner in fault mode
Gas valve faulty or faulty
modulation valve control;
or vent system blocked
Check the gas valve.
Check the vent system.
Press reset button
R
.
FD
Burner in a fault state and
additional fault B7 is displayed
Boiler coding card is
missing
Insert the boiler coding card.
Press reset button
R
.
Replace control unit if fault
persists.
Burner in a fault state
Fault, burner control
unit
Check ignition electrodes and
connecting cables. Check
whether a strong interference
(EMC) field exists near the
appliance. Press reset button
R
.
Replace control unit if fault
persists.
FE
Burner in fault mode
Damaged or incorrect
boiler coding card or
main PCB
Press reset button
R
. If the fault
persists, check the boiler coding
card or replace it or the control
unit.
FF
Burner in fault mode
Internal fault or reset
button
R
blocked
Restart the equipment.
Replace the control unit if the
equipment will not restart.
*1
Control mode:..............Boiler/burner fully operational (fault code must be verified and reset).
Burner in fault mode:.....Boiler control requires manual reset before burner can resume operation.
Burner blocked: ...........If fault cause is corrected, burner resumes operation.