BoilerFaultCodesYour boiler's internal computer has encountered a software glitch or a communication failure that is preventing it from starting up safely.
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
What causes this fault?
This fault occurs when the boiler's main control board experiences a critical internal failure or loses the ability to talk to other sensors. It is essentially a software crash where the 'brain' of the boiler can no longer verify that it is safe to operate. This is usually caused by a component failure on the circuit board itself or a loose connection in the internal wiring.
DIY fix possible
Locate the reset button or turn the selector switch to the reset positionHold for five seconds and releaseWait two minutes to see if the boiler restarts and the code clears
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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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