Viessmann Vitodens 300 Service Instructions Manual page 81

Checking and acknowledging faults
Displayed Const.
fault code
dd
dE
E4 X
E5 X
E6 X
F0 X
Weat- System
her- character-
comp. istics
X
X
X Burner
blocked
X Burner
blocked
X Burner in
fault state
X Burner
blocked
Troubleshooting
(cont.)
Cause Remedy
Room temperature Check the
sensor heating cir- room tem-
cuit A1 lead break perature sen-
sor for
heating cir-
cuit A1
Heating circuit M2 Check the
room temperature room tem-
sensor lead break perature sen-
sor for
heating cir-
cuit M2
Fault - supply vol- Replace con-
tage trol unit
Internal fault Check the
ionisation
electrode and
leads. Check
flue gas sys-
tem for
soundness.
Press E.
Flue gas/air supply Check the
system blocked flue gas/air
supply sys-
tem. Check
the differen-
tial pressure
sensor.
Press E.
Internal fault Replace con-
trol unit
81