Viessmann Vitotronic 300 Installation And Service Instructions Manual page 46

Troubleshooting
Fault Codes
(continued)
Displayed System characteristics
fault code
D7 Control mode
D8 Control mode
DA Control mode without
room influence.
DB Boiler cools down.
DC Control mode without
room influence.
DD Control mode without
room influence.
DE Control mode without
room influence.
DF Control mode without
room influence.
E1 Burner control unit in
a fault state.
E2 Burner control unit in
a fault state.
Shortage of gas to gas pressure
switch 2; valve leak test.
E3 Burner control unit in a fault
state.
E4 Burner shuts down
E5 Burner control unit in
a fault state.
EE Burner control unit in a fault
state.
EF Burner control unit in a fault
state.
46
Vitotronic 300, GW5B Installation and Service
Cause
Input DE2 at extension EA1
reports a fault.
Input DE3 at extension EA1
reports a fault.
Short circuit, room temperature
sensor, heating circuit without
mixing valve A1 (heating circuit 1).
Short circuit, room temperature
sensor, heating circuit with mixing
valve M2 (heating circuit 2).
Short circuit, room temperature
sensor, heating circuit with mixing
valve M3 (heating circuit 3).
Lead break, room temperature
sensor, heating circuit without
mixing valve A1 (heating circuit 1).
Lead break, room temperature
sensor, heating circuit with mixing
valve M2 (heating circuit 2).
Lead break, room temperature
sensor, heating circuit with mixing
valve M3 (heating circuit 3).
Valve 1 not tight / gas pressure
switch 2 does not open.
Valve 2 not tight; gas pressure
switch 2 does not close.
Gas valve does not open; gas
valve leaking; gas pressure
switch 2 faulty.
Lead break, strapping plug fJ.
Multiple detection of
undervoltage with return and
renewed undervoltage.
Internal fault of the burner
control unit and during test of
ionization input.
Internal error in feedback from
gas safety valves; output relay
does not respond.
Internal error in feedback from
gas safety valves; output
relay does not respond.
Measures
Remove fault at appliance
concerned.
Remove fault at appliance
concerned.
Check room temperature
sensor (see page 84).
Check room temperature
sensor (see page 84).
Check room temperature
sensor (see page 84).
Check room temperature
sensor (see page 84).
Check room temperature
sensor (see page 84).
Check room temperature
sensor (see page 84).
Check setting of gas pressure
switch 2; check connecting
cable; replace gas valve.
Check setting of gas pressure
switch 2; check connecting
cable; replace gas valve.
Replace gas valve.
Check strapping plug fJ.
Check the power supply.
Replace burner control
unit.
Reset burner control unit;
replace burner control unit.
Reset burner control unit;
replace burner control unit.