E135 High
Your boiler's internal computer has encountered a software glitch or a communication failure that is preventing it from starting up safely.
Technical description: Internal error
Typical repair cost: £250-£450 (including labour)
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
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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Parts commonly replaced
- Main Printed Circuit Board (PCB)
- Wiring harness
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