BoilerFaultCodesIdeal Outside Sensor Fault Fault Code
Also written as OUTSIDESENSORFAULT — same fault.
The Ideal Outside Sensor Fault fault code means: your boiler has lost connection with the sensor that measures the temperature outside, meaning it may not heat your home as efficiently as usual.. It appears on 9 Ideal models in our database.
Technical description: Wiring or resistance issues with the external outside temperature sensor.
What causes the Ideal Outside Sensor Fault fault?
This fault occurs when the boiler can no longer communicate with the small sensor box located on your external wall. The most common reasons are moisture entering the sensor casing causing corrosion, or a break in the thin communication wire leading back to the boiler.
This fault is more frequent during autumn and winter when increased rainfall and freezing temperatures can damage exposed external wiring or sensor seals.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Ideal models that show the Outside Sensor Fault fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal Outside Sensor Fault fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026