Viessmann MatriX Service Instructions For Contractors page 39

Fault codes
(cont.)
Shown on dis- System characteristics
play
F E5, F EC, Fault in burner control unit
F Ed, F EE, area
F FF
F Fd Fault in burner control unit
area
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
Cause
Internal system fault and
EMC
See the following table
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
Troubleshooting
Measures
Reset the burner control unit. Re-
place the burner control unit if the
fault persists.
See the following table
Measure
Replace programming unit
Check wiring
Disconnect 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
inlet strainer.
Check whether external volt-
age present.
Check on-site connection.
Check whether external volt-
age present.
Check on-site connection.
Check whether external volt-
age present.
Check on-site connection.
Disconnect the plug from fuel
valve 1. Reset the burner
control unit. 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.
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