1 High

Daikin 1 Fault Code

The Daikin 1 fault code means: your hybrid system has detected that the water temperature inside the unit is getting too hot, so it has temporarily shut down to prevent damage.. It appears on 3 Daikin models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Temperature too high
Typical repair cost £150-350 (including labour)

Engineer required

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

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Daikin models that show the 1 fault code

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

Source

Daikin 1 fault code information on this page is sourced and cross-checked against the official Daikin service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026