42
Displayed fault
code
System characteristics
Cause
Measures
F F1
Burner control unit in a fault
state; system cools down.
Flue gas temperature lim-
iter has responded
■
Flue gas temperature
too high
■
Excessive gas through-
put
■
Wait until temperature falls below
the permissible flue gas tempera-
ture.
■
Check the system pressure.
■
Check heat exchanger surfaces
for soiling.
■
Reset the burner control unit.
■
Check the CO
2
setting.
■
Adjust gas throughput in accord-
ance with the rated boiler heating
output. See "Specification" for
connected values.
F F2
Burner control unit in a fault
state; system cools down.
Boiler water temperature
limiter has responded.
Boiler water temperature
too high.
■
Wait until temperature falls below
the permissible boiler water tem-
perature.
■
Reset the 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
Internal system faults will be shown if the correct pro-
gram sequence can no longer be guaranteed.
Displayed fault
code
System characteristics
Cause
Measures
F E5, F EC,
F ED, F FF
Fault in burner control unit
area
Internal system fault and
EMC
Reset the burner control unit. Re-
place 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.
Troubleshooting
Fault codes
(cont.)
5816717
Diagnosis
