43
Fault code dis-
played
System characteristics
Cause
Measures
F F9
No feedback from fan
Fan faulty, external fan
power supply not connec-
ted or faulty, cable "
a-Ö
A"
faulty or broken, fan
blocked (poss. by foreign
bodies)
Check cable "
a-Ö
A", check exter-
nal power supply, replace cable or
fan, remove foreign body.
F FA
Fan runs without demand;
burner control unit in a fault
state.
Fan does not reach idle
state, cable "
a-Ö
A" faulty,
fan faulty, burner control
unit faulty
Fan subject to wind influence,
check flue outlet and fan, replace
cable "
a-Ö
A", replace fan, replace
burner control unit.
F FB
Burner does not start
■
Combustion chamber
pressure too high
(LDW2)
■
Condensate backed up
■
Flue gas path blocked
■
Flue gas damper does
not open or close.
■
Burner control unit con-
figured incorrectly
■
Check condensate drain and flue
gas path for blockages.
■
Check flue gas damper.
■
Check motorised flue gas damp-
er operating parameters.
Internal system faults
If the correct program sequence can no longer be
guaranteed, internal system faults occur.
Shown on dis-
play
System characteristics
Cause
Measures
F E5, F EC, F
Ed, F Fd, F FF
Fault in burner control unit
area
Internal system fault and
EMC
Reset burner control unit. Replace
the burner control unit if the fault
persists.
F FD
Fault in burner control unit
area
See the following table
See the following table
Detailed error codes for F FD
Detailed er-
ror code
Component/signal Cause of fault
Measure
30
Reset button
Programming unit faulty
Wiring
Replace programming unit.
Check wiring.
31
Fuel valve 2 feed-
back
Incorrect return voltage
(e.g. DC voltage)
Actuator faulty
Remove plug from fuel valve 2, reset burner con-
trol unit and check error messages. If F Fd recurs,
replace burner control unit. Otherwise, replace
fuel valve 2.
32
Air pressure switch
1
High switching se-
quence, switch flutters
External voltage
Check flue gas path and combustion. Check set-
ting LDW1. Check burner gauze assembly for
soiling.
34
Gas pressure
switch 1
High switching se-
quence, switch flutters
External voltage
Check the gas supply. Check setting GDW1 and
gas train intake screen.
35
Plug 41 demand T2 High switching se-
quence, switch flutters
External voltage
Check whether external voltage present.
Check on-site connection.
Troubleshooting
Fault codes
(cont.)
5812086
Diagnosis
