BoilerFaultCodesMain 2 Red Flashes Fault Code
Also written as 2REDFLASHES — same fault.
The Main 2 Red Flashes fault code means: your boiler has become too hot and has shut itself down as a safety precaution to prevent damage.. It appears on 2 Main models in our database.
Technical description: Boiler overheat tripped
What causes the Main 2 Red Flashes fault?
This fault occurs when the water inside the heat exchanger reaches an unsafe temperature, triggering a safety sensor to cut the power. The most common reasons are a pump failure preventing water from moving through the system or a blockage such as lime scale or sludge restricting the flow. Sometimes, the overheat thermostat itself has simply become faulty and is sending a false signal to the control board.
This fault is more common in winter when the heating is first turned on after a long summer break, as circulating pumps can often seize or stick during months of inactivity.
DIY fix possible
Check that your radiator valves are open and not turned to off or zeroEnsure your system water pressure is between 1 and 1.5 bar on the pressure gaugeTurn the selector switch to the reset position for five seconds and then back to your desired setting
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A cover plan would handle faults like 2 Red Flashes: no call-out fees, no surprise bills.
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Main models that show the 2 Red Flashes fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Main 2 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