BoilerFaultCodesWhat the manual says
Manufacturer manualThe outside temperature of the sensor connected to the control unit will be utilised internally and transmitted via LON BUS to any connected Vitotronic 050.
What causes this fault?
This fault occurs when the boiler's main control board loses the data connection from the outdoor weather sensor. The most common cause is a loose connection or a break in the wiring between the boiler and the sensor, though it can also be caused by a software glitch in the communication module. Because the boiler can no longer see the outside temperature, it will stop modulating based on the weather and revert to a basic backup setting.
This fault often becomes noticeable during the autumn or spring when fluctuating outdoor temperatures cause the expansion and contraction of the sensor's delicate electrical components.
DIY fix possible
Check for any visible damage to wiring leading to the outdoor sensorSwitch the boiler off and back on at the fused spur to refresh the connectionIf you have a Vitotronic 050 controller, check that it is powered on
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Related fault codes
All 60 fault codes on the Vitodens 300-W
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