43
Detailed er-
ror code
Component/signal Cause of fault
Measure
35
Plug 41 demand T2 High switching se-
quence, switch flutters
External voltage
Check whether external voltage present.
Check on-site connection.
36
Plug 90 T8
High switching se-
quence, switch flutters
External voltage
Check whether external voltage present.
Check on-site connection.
37
Plug 90 T7 SK
High switching se-
quence, switch flutters
External voltage
Check whether external voltage present.
Check on-site connection.
38
Fuel valve 1 feed-
back
Incorrect return voltage
(e.g. DC voltage)
Actuator faulty
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.
3A
Ignition feedback
Incorrect return voltage
(e.g. DC voltage)
Actuator faulty
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.
3B
Air pressure switch
2
For type CM3C only:
High switching se-
quence, switch flutters
External voltage
Check flue gas path and reheating surfaces.
Check air pressure switch 2 setting.
60
Hall signal fan feed-
back (RM-N)
Fan speed too high. In-
correct fan or incorrect
coding card
Check the fan. Check coding card.
Faults without fault display
Fault
Cause of fault
Measure
Combustion faults due to
pulsation
Excessive gas throughput
Adjust gas throughput in accordance with the rated
boiler heating output.
Insufficient or excessive air
Condensate backed up in flue
system
Check condensate drain.
Flue outlet not installed cor-
rectly
Check flue outlet and flue system.
Thermo-acoustics/combus-
tion noise
Incorrect CO
2
settings; insuffi-
cient or excessive air
Adjust burner in accordance with the details on
page 16 onwards.
CO
2
content too low
Incorrect setting
Check whether the burner has been adjusted to the
correct gas type; change gas restrictor if required
(see page 10 onwards).
Adjust burner in accordance with the details on
page 16 onwards.
CO formation or burner is
very sooty.
Insufficient or excessive air
Correct the settings. Check ventilation in installation
room.
Insufficient draught in flue
system
Check flue system.
Flame tears off during oper-
ation
Intake strainer of gas train
soiled
Remove flange and clean strainer. See page 28.
Flue gas temperature too
high
Excessive gas throughput
Adjust gas throughput in accordance with the rated
boiler heating output. Check condition of heating
surfaces. Clean if required.
Troubleshooting
Fault codes
(cont.)
5816717
Diagnosis
