How much does it cost to fix Atag error code E03?

Typical repair cost for the Atag E03 fault is £150-300 including labour.

E03 High

Atag E03 Fault Code

Q: What does the Atag E03 fault code mean?

Your boiler has detected that the water inside the heating system is not reaching or maintaining the correct temperature, leading the unit to stop operating to prevent damage.

The Atag E03 fault code means: your boiler has detected that the water inside the heating system is not reaching or maintaining the correct temperature, leading the unit to stop operating to prevent damage.. It appears on 2 Atag models in our database.

Technical description: °C flow water temperature T1

Typical repair cost £150-300 (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 E03 fault code

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

A200 Repair: £100-180
Q 25CR Repair: £150-300

Source

Atag E03 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 27 April 2026