BoilerFaultCodesMain E135 Fault Code
The Main E135 fault code means: your boiler has lost its gas supply, meaning it cannot light the flame to provide heating or hot water.. It appears on 1 Main model in our database.
Technical description: Interruption of gas supply
What causes the Main E135 fault?
This fault occurs when the boiler's internal safety sensors detect that gas is not reaching the burner or the flame isn't staying lit. It is often caused by a closed gas meter valve, a blockage in the supply pipe, or a mechanical failure of the gas valve within the unit itself. In some cases, the boiler may simply have air trapped in the system after a period of non-use or a recent gas works.
This fault is slightly more common during the first cold snap of winter, as gas meters or external regulators can occasionally freeze or stick after periods of inactivity.
DIY fix possible
Check that your gas emergency control valve (usually by the meter) is in the 'on' position.If you have a pre-payment meter, check that you have sufficient credit and the valve hasn't closed.Check if other gas appliances, like a hob, are working to confirm if the issue is with the boiler or the whole house supply.Try resetting the boiler by turning the selector switch to the 'R' position for at least five seconds.
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Gas Safe Register →Main models that show the E135 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Main E135 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 27 April 2026