BoilerFaultCodesBaxi 1 flash green Fault Code
Also written as 1FLASHGREEN — same fault.
The Baxi 1 flash green fault code means: your boiler has detected that it is heating up too quickly or getting too hot, usually because the water isn't moving through the system properly.. It appears on 4 Baxi models in our database.
Technical description: Temperature protection: Maximum flow temperature exceeded, Flow temperature rise rate too high, Excessive difference between flow and return temperature
DIY fix possible
Check that your pump is running and hasn't seizedEnsure all radiator valves are open to allow water flowCheck that the system pressure is at the correct level (usually 1.0 to 1.5 bar)Bleed all radiators to remove trapped air pockets
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Baxi models that show the 1 flash green fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Baxi 1 flash green fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.
- Baxi 613 Heat manual (PDF)
- Baxi 800 Heat (range) manual (PDF)
- Baxi EcoBlue Advance Heat manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026