BoilerFaultCodesDaikin E1-73 Fault Code
Also written as E173 — same fault.
The Daikin E1-73 fault code means: your boiler's internal computer has encountered a software glitch or a technical hiccup and needs a system restart to try and clear the error.. It appears on 1 Daikin model in our database.
Technical description: Printed circuit board (PCB) error – try resetting the boiler
What causes the Daikin E1-73 fault?
This fault occurs when the boiler's main control board experiences a communication failure or a data processing error within its internal memory. It is often caused by a sudden electrical surge, loose wiring connections, or the natural degradation of the electronic components on the circuit board over time.
DIY fix possible
Locate the Reset button on the boiler control panelPress and hold the Reset button for 2-3 secondsWait for the boiler to complete its startup sequence and check if the code clears
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Gas Safe Register →Daikin models that show the E1-73 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Daikin E1-73 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