Faults Without Fault Display - Viessmann Vitocrossal 200 Service Instructions For Contractors

Troubleshooting
Fault codes
(cont.)
Detailed er- Component/signal Cause of fault
ror code
36 Plug 90 T8
37 Plug 90 T7 SK
38 Fuel valve 1 feed-
back
3A Ignition feedback
3B Air pressure switch
2
60 Hall signal fan feed-
back (RM-N)

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
44
High switching se-
quence, switch flutters
External voltage
High switching se-
quence, switch flutters
External voltage
Incorrect return voltage
(e.g. DC voltage)
Actuator faulty
Incorrect return voltage
(e.g. DC voltage)
Actuator faulty
High switching se-
quence, switch flutters
External voltage
Fan speed too high. In-
correct fan or incorrect
coding card
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
Measure
Check whether external voltage present.
Check on-site connection.
Check whether external voltage present.
Check on-site connection.
Remove plug from fuel valve 1, reset burner con-
trol unit and check error messages. If F Fd recurs,
replace burner control unit. Otherwise, replace
fuel valve 1.
Disconnect cable from ignition module, reset
burner control unit and check error messages. If
F Fd recurs, replace burner control unit. Other-
wise, replace ignition module.
Check flue gas path and reheating surfaces.
Check air pressure switch 2 setting.
Check the fan. Check coding card.
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 on
page 16 onwards.
Check whether the burner has been adjusted to the
correct gas type; change gas restrictor if required
(see page 11 onwards).
Adjust burner in accordance with the details on
page 16 onwards.
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.