Boiler System Fault Codes - Viessmann Vitocrossal 300 CA3 2.5 Installation And Service Instructions Manual

Vitocrossal 300 CA3 Series 2.5 to 6.0 Installation/Service

Boiler System Fault Codes

Displayed System characteristics
fault code
0f Control mode.
10 Operates as if the outdoor
temperature was 32°F (0°C).
18 Operates as if the outdoor
temperature was 32°F (0°C).
20 Standalone control unit without
supply temperature sensor
(possibly supply temperature not
high enough)
28 Standalone control unit without
supply temperature sensor
(possibly supply temperature not
high enough)
30 H With DHW tank: DHW pump
ON, boiler is maintained at set
tank temperature.
H Without DHW tank: Boiler is
regulated by the temperature
controller.
38 H With DHW tank: DHW pump
ON, boiler is maintained at set
tank temperature.
H Without DHW tank: Boiler is
regulated by the temperature
controller.
40 Mixing valve is being closed.
44 Mixing valve is being closed.
48 Mixing valve is being closed.
Cause
Service "0f" is only displayed in
the fault history.
Short circuit, outdoor
temperature sensor.
Lead break, outdoor temperature
sensor.
Short circuit, common supply
temperature sensor
Lead break, common supply
temperature sensor
Short circuit, boiler water
temperature sensor
Lead break, boiler water
temperature sensor
Short circuit, supply temperature
sensor, heating circuit with mixing
valve M2 (heating circuit 2).
Short circuit, supply temperature
sensor, heating circuit with mixing
valve M3 (heating circuit 3).
Lead break, supply temperature
sensor, heating circuit with mixing
valve M2 (heating circuit 2).
Troubleshooting
Measures
Service required
Note: After servicing, set code
"24:0".
Check outdoor temperature
sensor.
Check outdoor temperature
sensor.
Check the supply temperature
sensor.
Check the supply temperature
sensor.
Check boiler water temperature
sensor.
Check boiler water temperature
sensor.
Check supply temperature
sensor.
Check supply temperature
sensor.
Check supply temperature
sensor.
177