84
Displayed fault
code
System characteristics
Cause
Measures
F5
Burner in a fault state
The air pressure switch
does not respond.
Check air pressure switch and re-
place if necessary.
Press reset button
R
.
F6
Burner in a fault state
Fuel valves are not actu-
ated or no feedback from
fuel valve BV 2
Check connecting cables and plug-
in connections of the fuel valves or
replace fuel valve BV 2.
Press reset button
R
.
F8
Burner in a fault state
Fuel valve BV 1 closes
late.
Check nozzle; vent oil line; check
solenoid valve.
Press reset button
R
.
F9
Burner in a fault state
Fan speed too low at
burner start
Radial fan does not start.
CO limiter or fire safety
switch locked.
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.
FA
Burner in a fault state
Fan idle state is not
reached.
Check fan and connecting cables
to fan.
Press reset button
R
.
Fb
Burner in a fault state
3 x flame blow-off during
operation
Check oil supply, check nozzle.
Press reset button
R
.
Fd
Burner in a fault state
Boiler coding card missing
or burner control unit fault.
Insert the boiler coding card.
Press reset button
R
.
Replace control unit if fault per-
sists.
Fd
Burner in a fault state and ad-
ditional fault b7 is displayed.
Solenoid coil faulty
Control unit faulty
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.
FE
Burner blocked or in a fault
state
Boiler coding card or main
PCB faulty, or incorrect
boiler coding card
Press reset button
R
. If the fault
persists, check the boiler coding
card and replace boiler coding card
or control unit if necessary.
FF
Burner locked out
Internal error
Restart the appliance. Replace the
control unit if the appliance will not
restart.
Troubleshooting
Fault codes
(cont.)
6136330
Service