Viessmann Vitocrossal 300 Service Manual page 85

Vitocrossal 300 CU3A 26 to 57 Service
Fault Codes
(continued)
Fault code on display
F8
F9
FA
FC
FD
FE
FF
*1 Control mode:
Burner in fault mode: Boiler control requires manual reset before burner can resume operation.
Burner blocked:
System behavior*1
Burner in fault mode
Burner in fault mode
Burner in fault mode
Burner in fault mode
Burner in a fault state and
additional fault B7 is displayed
Burner in a fault state
Burner in fault mode
Burner in fault mode
Boiler/burner fully operational (fault code must be verified and reset).
If fault cause is corrected, burner resumes operation.
Cause
Gas valve closes too
late
Fan speed too low
during burner start
Fan not at standstill
Gas valve faulty or faulty
modulation valve control;
or vent system blocked
Boiler coding card is
missing
Fault, burner control
unit
Damaged or incorrect
boiler coding card or
main PCB
Internal fault or reset
button R blocked
Troubleshooting
Corrective action
Check the gas valve.
Check both control wiring/
connections.
Press reset button R.
Check the fan, the fan cables
and power supply. Check the
fan control.
Press reset button R.
Check the fan, the fan
connecting cables and fan
control. Check the fan control.
Press reset button R.
Check the gas valve.
Check the vent system.
Press reset button R.
Insert the boiler coding card.
Press reset button R.
Replace control unit if fault
persists.
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.
Press reset button R. If the fault
persists, check the boiler coding
card or replace it or the control
unit.
Restart the equipment.
Replace the control unit if the
equipment will not restart.
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