Viessmann Vitoplus 300 Service Instructions Manual page 72

Troubleshooting
Fault codes
(cont.)
Display fault System char-
code acteristics
CF Control mode
dA Control mode
without room
influence
db
dd
dE
E4 Burner
blocked
E5 Burner control
unit fault
E6 Burner control
unit fault
F0 Burner
blocked
72
Cause
Communication fault
LON communication
module
Room temperature sen-
sor, heating circuit A1
shorted out
Room temperature sen-
sor, heating circuit with
mixer M2 shorted out
Room temperature sen-
sor, heating circuit A1
lead broken
Room temperature sen-
sor, heating circuit with
mixer M2 lead broken
Supply voltage fault
Internal fault
The oil preheater does
not respond inside the tol-
erated time
Internal fault
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 circuit
A1 and the remote
control DIP switch
settings (see
page 97)
Check the room
temperature sen-
sor, heating circuit
with mixer M2 and
the remote control
DIP switch set-
tings (see
page 97)
Replace the con-
trol unit
Replace the con-
trol unit
Press "E".
Check the oil pre-
heater and re-
place, if required
Press "E".
Replace the con-
trol unit