BoilerFaultCodesDaikin Err HJ-09 Fault Code
Also written as ERRHJ09 — same fault.
The Daikin Err HJ-09 fault code means: your boiler has detected that there is not enough water pressure in the system to operate safely, which has caused it to shut down.. It appears on 1 Daikin model in our database.
Technical description: Low pressure
DIY fix possible
Locate the metal braided filling loop underneath or near your boiler.Slowly open the valve(s) to allow water into the system while watching the pressure gauge.Close the valves tightly once the pressure reaches between 1.0 and 1.5 bar.
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Daikin models that show the Err HJ-09 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Daikin Err HJ-09 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 7 July 2026