Viessmann Vitocrossal 200 Service Instructions For Contractors page 40

Troubleshooting
Fault codes
(cont.)
Fault code dis- System characteristics
played
F FA Fan runs without demand;
burner control unit in a fault
state.
F FB Excessive combustion cham-
ber pressure, burner control
unit in a fault state
Internal system faults
If the correct program sequence can no longer be
guaranteed, internal system faults occur.
Shown on dis- System characteristics
play
F E5, F EC, F Fault in burner control unit
Ed, F Fd, F FF area
Faults without fault display
Fault
Combustion faults due to
pulsation
Thermo-acoustics/combus-
tion noise
CO content too low
2
CO formation or burner is
very sooty.
Flame extinguishes during
operation
Flue gas temperature too
high
40
Cause
Fan does not reach idle
state, cable "
fan faulty, burner control
unit faulty
Flue gas path or conden-
sate path blocked off
Cause
Internal system fault and
EMC
Cause of fault
Excessive gas throughput
Insufficient or too much air
Condensate banked up in
flue system
Incorrect flue outlet
Incorrect CO settings; insuf-
2
ficient or excessive air
Incorrect setting
Insufficient or too much air
Insufficient draught in flue
system
Inlet strainer of gas train con-
taminated
Excessive gas throughput
Measures
Fan subject to wind influence,
A" faulty, check flue outlet and fan, replace
a-Ö
cable "
a-Ö
burner control unit.
Check flue gas path or condensate
path and clean if required.
Measures
Reset burner control unit. Replace
the burner control unit if the fault
persists.
Action
Adjust gas throughput in accordance with the rated
boiler heating output.
Check condensate drain.
Check flue outlet and flue system.
Adjust burner in accordance with the details from
page 16.
Check whether the burner has been adjusted to the
correct gas type; change gas restrictor if required
(see from page 11).
Adjust burner in accordance with the details from
page 16.
Correct the settings. Check ventilation in installation
room.
Check flue system.
Remove flange and clean strainer.
Adjust gas throughput in accordance with the rated
boiler heating output. Check condition of secondary
heating surfaces of the boiler and clean if required.
A", replace fan, replace