BoilerFaultCodesDaikin UA-64 Fault Code
Also written as UA64 — same fault.
The Daikin UA-64 fault code means: your boiler's computer memory card is experiencing a communication error or has failed during an internal update, causing the system to stop working.. It appears on 1 Daikin model in our database.
Technical description: Blocking during boiler chip card (BBC) update
What causes the Daikin UA-64 fault?
This fault occurs when the boiler's main control board loses its connection with the small plug-in memory chip that contains the unit's specific operating instructions. It is usually triggered by a physical hardware failure on the chip itself or a data corruption error that happens while the system is trying to update its internal software.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Daikin models that show the UA-64 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Daikin UA-64 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