BoilerFaultCodesMain 6 Red Flashes Fault Code
Also written as 6REDFLASHES — same fault.
The Main 6 Red Flashes fault code means: your boiler has detected a general internal error, often linked to a small electronic glitch or a sensor that is failing to communicate correctly with the main controls.. It appears on 2 Main models in our database.
Technical description: Miscellaneous
What causes the Main 6 Red Flashes fault?
This fault occurs when the boiler's internal computer receives conflicting information or loses contact with the main components that manage the heating process. It is typically caused by a communication breakdown between the electronic control board and the sensors, or small electrical fluctuations that disrupt the system's logic. In many cases, it indicates that the 'brain' of the boiler is no longer able to safely coordinate the startup sequence.
DIY fix possible
Locate the reset knob on the front control panelTurn the knob to the 'R' (Reset) position and hold for 5 secondsRelease the knob and wait to see if the error light clears and the boiler restarts
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Main models that show the 6 Red Flashes fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Main 6 Red 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