Viessmann VITODENS 111-W Installation And Service Instructions Manual page 46

Troubleshooting
Fault messages on the display
Displayed System characteris-
fault code tics
Fd Burner blocked
FF Burner blocked
Pressing reset
r
46
(cont.)
Cause
Fault, burner con-
trol unit
Fault, burner con-
trol unit
Turn rotary selector "rt" to "U
RESET" until "SERV" is shown.
Within 2 s return the rotary selector to the
control range.
Measures
Check ignition electrodes
and connecting cables.
Check whether a strong
interference (EMC) field
exists near the appliance.
Press "RESET" (see
page 46).
Replace control unit if
fault persists.
Check ignition electrodes
and connecting cables.
Check whether a strong
interference (EMC) field
exists near the appliance.
Press "RESET" (see
page 46).
Replace control unit if
fault persists.