201 Medium

Atag 201 Fault Code

The Atag 201 fault code means: your boiler's hot water sensor has failed, which means the system cannot accurately heat your taps or showers.. It appears on 13 Atag models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: DHW Probe Damaged (Combi)
Typical repair cost £120-£190 (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 201 fault code

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

Source

Atag 201 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