Viessmann Vitoladens 300-C Installation And Service Instructions Manual page 84

Troubleshooting
Fault codes
(cont.)
Displayed fault System characteristics
code
F5 Burner in a fault state
F6 Burner in a fault state
F8 Burner in a fault state
F9 Burner in a fault state
FA Burner in a fault state
Fb Burner in a fault state
Fd Burner in a fault state
Fd Burner in a fault state and ad-
ditional fault b7 is displayed.
FE Burner blocked or in a fault
state
FF Burner locked out
84
Cause
The air pressure switch
does not respond.
Fuel valves are not actu-
ated or no feedback from
fuel valve BV 2
Fuel valve BV 1 closes
late.
Fan speed too low at
burner start
Radial fan does not start.
CO limiter or fire safety
switch locked.
Fan idle state is not
reached.
3 x flame blow-off during
operation
Boiler coding card missing
or burner control unit fault.
Solenoid coil faulty
Control unit faulty
Boiler coding card or main
PCB faulty, or incorrect
boiler coding card
Internal error
Measures
Check air pressure switch and re-
place if necessary.
Press reset button R.
Check connecting cables and plug-
in connections of the fuel valves or
replace fuel valve BV 2.
Press reset button R.
Check nozzle; vent oil line; check
solenoid valve.
Press reset button R.
Check the fan, fan connecting ca-
bles, fan power supply and fan
control.
Press reset button R.
If a fire safety switch or CO limiter
is installed, check whether one of
these safety mechanisms has re-
sponded.
If CO limiter has responded: Check
flue system, boiler and trap for es-
caping flue gas.
Check fan and connecting cables
to fan.
Press reset button R.
Check oil supply, check nozzle.
Press reset button R.
Insert the boiler coding card.
Press reset button R.
Replace control unit if fault per-
sists.
Check solenoid coil by temporarily
replacing it or by swapping coil 1
with coil 2. If fault F6 is then dis-
played, replace solenoid coil.
Check coding address 38: If the
value is at 38:33, the control unit is
faulty.
Before replacing the control unit,
check while the control unit is
switched on to see if the green
LED on the ignition unit is flashing.
If the LED is not flashing, also re-
place the ignition unit.
Press reset button R. If the fault
persists, check the boiler coding
card and replace boiler coding card
or control unit if necessary.
Restart the appliance. Replace the
control unit if the appliance will not
restart.