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5790 733 - 07
Vitocrossal 300 CA3 Series 2.5 to 6.0 Installation/Service
Boiler System Fault Codes
(continued)
Troubleshooting
Displayed
fault code
System characteristics
Cause
Measures
dc
Control mode without room
influence.
Short circuit, room temperature
sensor, heating circuit with mixing
valve M3 (heating circuit 3).
Check room temperature sensor
(see page 186).
dd
Control mode without room
influence.
Lead break, room temperature sen-
sor, heating circuit without mixing
valve A1 (heating circuit 1).
Check room temperature sensor
(see page 186).
de
Control mode without room
influence.
Lead break, room temperature
sensor, heating circuit with mixing
valve M2 (heating circuit 2).
Check room temperature sensor
(see page 186).
df
Control mode without room
influence.
Lead break, room temperature
sensor, heating circuit with mixing
valve M3 (heating circuit 3).
Check room temperature sensor
(see page 186).
Displayed
fault code
System characteristics
Cause
Measures
E1
Burner control unit in a fault
state.
Valve 1 not tight / gas pressure
switch 2 does not open.
Check setting of gas pressure
switch 2; check connecting
cable; replace gas valve.
E2
Burner control unit in a fault
state.
Valve 2 not tight; gas pressure
switch 2 does not close.
Check setting of gas pressure
switch 2; check connecting
cable; replace gas valve.
Shortage of gas to gas pressure
switch 2; valve leak test.
Gas valve does not open; gas
valve leaking; gas pressure
switch 2 faulty.
Replace gas valve.
E4
Burner shuts down
Multiple detection of
undervoltage with return and
renewed undervoltage.
Check the power supply.
E5
Burner control unit in a fault
state.
Internal fault of the burner
control unit and during test of
ionization input.
Replace burner control unit.
EE
Burner control unit in a fault
state.
Internal error in feedback from
gas safety valves; output relay
does not respond.
Reset burner control unit; replace
burner control unit.
EF
Burner control unit in a fault
state.
Internal error in feedback from
gas safety valves; output relay
does not respond.
Reset burner control unit; replace
burner control unit.
F0
Operation according to internal
burner control unit defaults.
Communication error, burner
control unit.
Check plug and KM BUS to
burner control unit.
Burner Fault Codes
Fault display on the display interface of the control unit.
