Viessmann Vitocrossal 300 CA3 2.5 Installation And Service Instructions Manual page 185

Vitocrossal 300 CA3 Series 2.5 to 6.0 Installation/Service
Burner Fault Codes
Displayed System characteristics
fault code
F5 Air pressure switch shows no air
pressure, fan not running.
Air pressure switch switches off
during operation.
F6 Gas pressure switch notifies no
gas pressure.
F7 Fan pressure is produced during
the air pressure switch idle state
check.
Air pressure switch contact is not
in the idle state.
F8 Flame extinguishes during
operation.
Flame extinguishes during
operation.
F9 Fan not running; fan speed not
reached.
Status duration too long, fan
ramp-up.
Varying fan speed
No fan feedback.
Fa Fan runs without demand; burner
control unit in a fault state.
Fd Burner control unit in a fault
state; system cools down; burner
control unit locked out.
(continued)
Cause
Air pressure switch is faulty,
incorrectly connected or
incorrectly set.
Flue gas back pressure;
condensate backed up; air
pressure switch hose faulty;
connecting hose leaking.
Gas shut-off valve closed;
gas pressure switch faulty;
multiple problems with gas
supply.
Wind influence on fan.
Air pressure switch faulty.
Burner gauze assembly faulty.
Combustion characteristics not
ideal.
Fan faulty; cables are faulty or
broken.
Internal fault; fan cannot reach its
set value.
Fan faulty, cable a-ÖA faulty
or broken. Check cable a-ÖA;
check external power supply;
replace the cable or fan; remove
foreign bodies.
Fan faulty, external fan power
supply not connected or faulty
cable a-ÖA or cable broken, fan
blocked (poss. by foreign bodies).
Fan does not reach idle state,
cable a-ÖA faulty, fan faulty,
faulty burner control unit.
Burner control unit in a fault
state.
Measures
Replace air pressure switch,
connect or set correctly.
Remove flue gas back pressure;
check if condensate backed up;
reset burner control unit; replace
hose.
Open gas shut-off valve; check
gas flow pressure; replace gas
filter if required; reset burner
control unit; replace gas valve.
Check the flue draught (chimney)
Replace the air pressure switch.
Check burner gauze assembly;
replace if damaged.
Adjust burner
(see boiler service instructions).
Check cables and replace the fan
if required
Replace fan or burner control unit.
Check cable; replace cable a-ÖA
or fan.
Check cable a-ÖA; check
external power supply; replace
cable or fan; remove foreign
bodies.
Fan subject to wind influence,
check flue outlet and fan, replace
cable a-ÖA, replace fan, replace
burner control unit.
Read off fault at the burner
control unit display and
programming unit (boiler service
instructions).
Fault message to the burner control unit:
Note: If LON participant faults occur, "Fault participant"...
is displayed.
Troubleshooting
185