Viessmann VITODENS 200-W Service Instructions Manual page 77

Fault codes
(cont.)
Fault Const. Weath.-
code comp.
on the
display
CF X
dA X
db X
dd X
dE X
E4 X X
System char- Cause
acteristics
Control mode Communica-
tion fault,
LON com-
munication
module
Control mode Room tem-
without room perature
influence sensor, heat-
ing circuit A1
shorted out
Control mode Room tem-
without room perature
influence sensor, heat-
ing circuit
with mixer
M2 shorted
out
Control mode Room tem-
without room perature
influence sensor, heat-
ing circuit A1
lead broken
Control mode Room tem-
without room perature
influence sensor, heat-
ing circuit
with mixer
M2 lead bro-
ken
Burner Supply vol-
blocked tage fault
Troubleshooting
Measures
Replace the LON
communication
module.
Check the room
temperature sen-
sor, heating cir-
cuit A1.
Check the room
temperature sen-
sor, heating cir-
cuit with mixer
M2.
Check the room
temperature sen-
sor, heating cir-
cuit A1 and the
remote control
DIP switch set-
tings (see
page 104).
Check the room
temperature sen-
sor, heating cir-
cuit with mixer M2
and the remote
control DIP switch
settings (see
page 104).
Replace the con-
trol unit.
77