BoilerFaultCodesDaikin 11-65 Fault Code
Also written as 1165 — same fault.
The Daikin 11-65 fault code means: your boiler is struggling to keep the flame steady and will keep trying to restart itself until it succeeds.. It appears on 1 Daikin model in our database.
Technical description: Flame stabilisation error – wait for the boiler ignition trial
What causes the Daikin 11-65 fault?
This fault occurs when the boiler's internal computer detects an unstable flame that cannot be maintained safely during the ignition process. The most common reasons are a buildup of carbon on the sensing probes or a fluctuating gas supply that prevents the burner from staying lit. It essentially means the boiler is 'knocking at the door' but the flame isn't catching well enough to stay running.
DIY fix possible
Wait for the boiler to finish its automatic restart cyclesCheck that your gas meter has credit (if applicable)Ensure other gas appliances in your home are working correctly
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Gas Safe Register →Daikin models that show the 11-65 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Daikin 11-65 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