197
5790 733 - 07
Vitocrossal 300 CA3 Series 2.5 to 6.0 Installation/Service
Fault Codes
(continued)
Displayed
Fault Code
System Characteristics
Cause
Measures
F F4
No flame formation during
safety time; ionization flame
monitor reports no flame signal
Ignition electrode not set
correctly; electrodes grounded;
ignition unit faulty; burner control
unit faulty
Adjust ignition electrodes (see page
114); replace ignition unit; replace
burner control unit
F F4
No flame formation during
safety time; ionization flame
monitor reports no flame signal
Insulation body of ignition or
ionization electrode cracked
Replace ignition or ionization
electrode
F F4
Poor start-up characteristics,
rotary damper does not close,
solenoid valve does not switch
Servomotor faulty, servomotor
connecting cable faulty, solenoid
valve faulty, burner control unit
output relay faulty
Replace connecting cable; replace
servomotor; replace solenoid
valve; replace burner control unit
F F4
No flame builds during safety
time; ionization flame monitor
reports no signal
Incorrect gas type selected
Adjust gas type (see page 190)
F F4
No flame builds during safety
time; ionization flame monitor
reports no signal
Gas valve does not open
Check the connecting cable;
check the gas valve and replace
if required
F F4
No flame builds during safety
time; ionization flame monitor
reports no signal
Combustion characteristics not
ideal
Adjust the burner (see pages 93
and 94, if necessary, also adjust
the setting screws when the
burner is OFF to be able to start
the burner)
F F5
Air pressure switch 1, LDW1
shows no air pressure, fan does
not operate
Air pressure switch 1, LDW1
faulty, incorrectly connected or
incorrectly set
Replace air pressure switch 1,
connect or set correctly
F F5
Air pressure switch 1, LDW1
switches off during operation
Flue gas back pressure;
condensate built up; air pressure
switch 1, LDW1 hose faulty;
connecting hose leaking
Remove flue gas back pressure;
check if condensate banked up;
reset burner control unit; replace
hose
F F6
Gas pressure switch 1, GDW1
shows no gas pressure
Gas shut-off valve closed; gas
pressure switch faulty; multiple
problems with gas supply
Open gas shut-off valve; check
gas flow pressure; replace gas
filter if required; reset burner
control unit; replace gas valve
F F7
Fan pressure is created during
the idle state check of air
pressure switch 1, LDW1
Wind influence on fan
Check flue outlet or (chimney)
F F7
Contact of air pressure switch
1, LDW1 not closed in idle
state
Air pressure switch 1, LDW1
faulty
Replace air pressure switch 1,
LDW1
F F8
Flame extinguishes during
operation
Burner gauze assembly faulty
Check burner gauze assembly;
replace if damaged
F F8
Flame extinguishes during
operation
Combustion characteristics not
ideal
Adjust burner (see pages 93 and 94)
Burner Control Unit
