Low
F6 on Ideal Logic Max Combi

Your boiler is having trouble communicating with the temperature sensor located on the outside of your house, which helps it decide how hard to work based on the weather.

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.

What the manual says

Manufacturer manual

Outside Sensor Fault

From this model's manual
Verified against the Ideal Logic Max Combi installation & service manual, page 56.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler is unable to receive a clear electrical signal from the sensor mounted on your external wall. The most common reason is that moisture has entered the sensor casing, causing corrosion, or the thin wiring connecting it to the boiler has become damaged or loose and cannot complete the circuit.

This fault is often triggered during periods of heavy rain or high humidity, as moisture is more likely to breach the sensor's external weatherproofing.

DIY fix possible

Locate the reset button on the front of the boiler display.Press and hold the reset button for 2 seconds.If the code persists, check that the external sensor on your outside wall hasn't been blocked or damaged.

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