BoilerFaultCodesYour boiler has lost its gas supply or detected an internal error, causing it to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Internal error (interruption of gas supply)
What causes this fault?
This fault occurs when the boiler's control system detects that the burner has lost its fuel source or cannot confirm a flame is present. The most common reasons are an external disruption to your gas supply, a blocked burner, or a faulty internal component that regulates gas flow.
This fault often appears during the first cold snap of winter when increased demand on the local gas network or internal components being worked hard for the first time can expose existing weaknesses.
DIY fix possible
Check that your gas emergency control valve is in the open positionIf you have a prepayment meter, ensure you have credit and that the meter is not lockedCheck if other gas appliances, like a hob, are working to confirm gas flowReset the boiler by turning the selector switch to 'R' for five seconds
Find a Gas Safe engineer
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Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like E135 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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