BoilerFaultCodesDaikin 80-01 Fault Code
Also written as 8001 — same fault.
The Daikin 80-01 fault code means: your boiler has detected a problem with the sensor that monitors the temperature of the water returning to the unit, causing it to stop for safety.. It appears on 1 Daikin model in our database.
Technical description: Return temperature sensor error – reset the boiler
What causes the Daikin 80-01 fault?
This fault occurs when the boiler's control board stops receiving a reliable signal from the sensor that monitors the cool water coming back from your radiators. The most common reason is that the sensor has developed an internal electrical fault or the wiring connecting it to the main computer has become loose or damaged. Because the boiler can no longer safely track how much heat to add to the water, it shuts down to prevent overheating.
DIY fix possible
Press the Reset button on the boiler control panel onceWait for the boiler to complete its restart sequenceIf the code persists, contact a Gas Safe registered engineer
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Gas Safe Register →Daikin models that show the 80-01 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Daikin 80-01 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 27 April 2026