Outside Sensor Fault Low

Ideal Outside Sensor Fault Fault Code

Also written as OUTSIDESENSORFAULT — same fault.

The Ideal Outside Sensor Fault fault code means: your boiler is struggling to understand the outdoor temperature, which might make your heating feel less efficient or slightly inconsistent.. It appears on 7 Ideal models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Insecure wiring at boiler/sensor, or incorrect resistance values (31.0-35.0 kΩ at 0°C, 15.0-16.5 kΩ at 15°C, 7.7-8.5 kΩ at 30°C).

What causes the Ideal Outside Sensor Fault fault?

This fault occurs when the boiler loses a reliable electrical signal from the sensor located on your outside wall. The most common reasons are moisture getting into the sensor casing, wires becoming loose or corroded over time, or the internal component failing and sending an incorrect temperature reading.

This fault is more common during autumn and winter, as heavy rain or freezing conditions can accelerate the corrosion of exposed wiring or cause moisture ingress in the sensor.

Typical repair cost £90-180 (including labour)

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 27 April 2026