BoilerFaultCodesMain 6 Green Flashes Fault Code
Also written as 6GREENFLASHES — same fault.
The Main 6 Green Flashes fault code means: your boiler is experiencing a communication error or internal electronic fault that is preventing it from running properly.. It appears on 2 Main models in our database.
Technical description: Miscellaneous error
What causes the Main 6 Green Flashes fault?
This fault occurs when the boiler's internal computer, the Printed Circuit Board, loses the ability to send or receive messages from other components. It is often caused by a loose connection in the wiring or a hardware failure within the control board itself. Think of it like a computer crash where the system can no longer tell the boiler how to operate safely.
DIY fix possible
Locate the selector switch on the front of the boiler.Turn the switch to the 'Reset' position and hold it for five seconds.Turn the switch back to the 'On' position and wait for the boiler to restart.
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Main models that show the 6 Green Flashes fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Main 6 Green Flashes fault code information on this page is sourced and cross-checked against the official Main service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026