BoilerFaultCodesBaxi 1 green flash Fault Code
Also written as 1GREENFLASH — same fault.
The Baxi 1 green flash fault code means: your boiler has reached the correct temperature and is simply taking a natural rest; it is working exactly as it should.. It appears on 22 Baxi models in our database.
Technical description: Boiler temperature reached. No action required.
What causes the Baxi 1 green flash fault?
This occurs when the water inside the boiler has reached the target temperature set by your thermostat or the dials on the front of the unit. The burner shuts off temporarily because there is no more heat required at that moment, preventing the system from overheating. It is a standard part of the boiler's operating cycle and ensures energy is not wasted.
You may notice this more frequently in Spring and Autumn when the weather is milder and your home reaches its target temperature very quickly.
DIY fix possible
Check if your room thermostat is set to the desired temperatureWait for the boiler to restart automatically when the water temperature dropsNo further action is required as this is normal operation
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Baxi models that show the 1 green flash fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Baxi 1 green flash fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026