Viessmann Vitodens 100 WB1A Installation And Service Instructions Manual page 73

Fault finding
(cont.)
Display fault System char-
code acteristics
Fd Burner
blocked
FE Burner
blocked
Cause Remedy
Burner control unit Check the ignition elec-
fault trodes and leads. Check
whether a strong interfer-
ence (EMC) field exists
near the equipment.
Press"Reset".
If the fault is not re-
moved, replace the con-
trol unit.
Faulty main PCB Switch OFF the control
unit, if the equipment will
not restart.
Troubleshooting
73