BoilerFaultCodesDaikin 16-64 Fault Code
Also written as 1664 — same fault.
The Daikin 16-64 fault code means: your boiler has shut down because the exhaust gases are getting too hot, indicating a potential blockage or safety issue in the flue pipe.. It appears on 1 Daikin model in our database.
Technical description: Flue temperature signals overheating, the flue gas discharge path needs checking, Try resetting the boiler
What causes the Daikin 16-64 fault?
This fault occurs when the internal sensors detect that the exhaust gases are reaching dangerous temperatures that could damage the boiler or its surroundings. The most common reason is a buildup of debris or scale within the heat exchanger or a physical blockage in the flue pipe that prevents heat from escaping properly. In some cases, it can also be triggered by a faulty sensor sending an incorrect temperature reading to the main control board.
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 16-64 fault code
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Source
Daikin 16-64 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