Viessmann VITOCROSSAL 200 CM2 Service Instructions For Contractors page 44

Troubleshooting
Fault codes
(cont.)
Detailed fault code for fault F Fd
Detailed fault code Component/signal
30 Reset button
31 Fuel valve 2 feedback
32 Air pressure switch 1
34 Gas pressure switch 1
35 Plug 41 demand T2
36 Plug 90 T8
37 Plug 90 T7
38 Fuel valve 1 feedback
3A Ignition feedback
3B Air pressure switch 2
60 Hall signal fan feedback
(RM-N)
44
Cause of fault
Programming unit faulty, wir-
ing
Incorrect return voltage (e.g.
DC voltage), actuator faulty
High switching sequence,
switch flutters, external volt-
age
High switching sequence,
switch flutters, external volt-
age
High switching sequence,
switch flutters, external volt-
age
High switching sequence,
switch flutters, external volt-
age
High switching sequence,
switch flutters, external volt-
age
Incorrect return voltage (e.g.
DC voltage), actuator faulty
Incorrect return voltage (e.g.
DC voltage), actuator faulty
High switching sequence,
switch flutters, external volt-
age
Fan speed too high. Incor-
rect fan or incorrect coding
card
Measure
Replace programming unit
Check wiring
Disconnect the plug from fuel
valve 2, reset the burner con-
trol unit and check the fault
messages.
If fault F Fd recurs, replace
burner control unit; otherwise
replace fuel valve 2.
Check flue gas path and com-
bustion. Check setting LDW1.
Check burner gauze assem-
bly for contamination.
Check the gas supply. Check
setting GDW1 and gas train
intake screen.
Check whether external volt-
age is present.
Check on-site connection.
Check whether external volt-
age is present.
Check on-site connection.
Check whether external volt-
age is present.
Check on-site connection.
Disconnect the plug from fuel
valve 1, reset the burner con-
trol unit and check the fault
messages.
If fault F Fd recurs, replace
burner control unit; otherwise
replace fuel valve 1.
Disconnect cable from igni-
tion module, reset burner
control unit and check the
fault messages.
If fault F FD recurs, replace
burner control unit; otherwise
replace ignition module.
Check flue gas path and re-
heating surfaces.
Check air pressure switch 2
setting.
Check the fan.
Check coding card.