10 Low

Atag 10 Fault Code

The Atag 10 fault code means: your boiler has lost connection with the sensor that monitors the outdoor temperature, which might cause your heating to respond incorrectly to the weather.. It appears on 10 Atag 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: Outside sensor error (open, short circuit, or out of range)
Typical repair cost £90-160 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Atag models that show the 10 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Atag 10 fault code information on this page is sourced and cross-checked against the official Atag service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026