198
5790 733 - 07
Vitocrossal 300 CA3 Series 2.5 to 6.0 Installation/Service
Burner Control Unit
Fault Codes
(continued)
Internal system fault
Internal system faults are created if a fault-free program sequence can no longer be ensured.
Displayed Fault Code
System Characteristics Cause
Measures
F F9
Fan not running; fan
speed not reached
Fan faulty; cables are faulty
or broken
Check cables; replace fan if required
F F9
Status duration too
long, fan ramp-up
Internal fault; fan cannot
reach its set value
Replace fan or burner control unit
F F9
Varying fan speed
Fan faulty, cable
“
a-Ö
A“
faulty or broken
Check cable; replace cable
“
a-Ö
A“ or
fan if required
F F9
No fan feedback
Fan faulty; external power
supply to fan not connected
or faulty; cable “
a-Ö
A“
faulty or broken; fan blocked
(possibly by a foreign
object)
Check cable “
a-Ö
A“, check external
power supply; replace cable or fan;
remove foreign object
F FA
Fan runs without
demand; burner control
unit in a fault state
Fan has not stopped; cable
“
a-Ö
A“ faulty; fan faulty;
burner control unit faulty
Wind influence on fan; check flue
outlet and fan; replace cable
“
a-Ö
A“,
replace fan; replace burner control unit
F Fb
Burner not starting.
Combustion chamber
pressure too high;
burner control unit in a
fault state
Flue gas path or condensate
path blocked off. Excessive
combustion chamber
pressure (air pressure switch
2, LDW2)
Check flue gas path or condensate path
and clean if required
F Fb
Burner not starting.
Combustion chamber
pressure too high;
burner control unit in a
fault state
Motorized burner damper
does not open/close
Check motorized burner damper
F E5
,
F EC
,
F Ed
,
F Fd
,
F FF
Fault around burner
control unit
Internal system fault and
EMC
Reset burner control unit. Replace the
burner control unit if the fault persists.
Faults Without Fault Display
Fault Cause
Measures
Combustion fault
through pulsation
Excessive gas input
Adjust gas input in accordance with rated boiler heating output
Insufficient or excessive air
Condensate build up in flue
system
Check condensate drain.
Incorrect flue outlet
Check flue outlet and flue system.
Thermoacoustics/
combustion noise
Incorrect CO
2
settings;
insufficient or excessive air
Adjust burner in accordance with the details on pages 93 and 94.
CO
2
content too low Incorrect setting
Check that burner has been adjusted and adjust burner in
accordance with the details on pages 93 and 94.
CO is formed or
burner is very sooty
Insufficient or excessive air
Adjust correctly. Check ventilation of installation room.
Insufficient draught in flue
system
Check flue system.
Flame extinguishes
during operation
Inlet strainer of gas valve
contaminated
Remove flange and clean strainer.
