S.3 High
Your boiler is struggling to light its flame, meaning your heating and hot water will likely stop working soon.
Technical description: Heating mode error – ignition problem
Typical repair cost: £120-£350 (including labour)
DIY fix possible
Check that your gas pre-payment meter (if you have one) has creditEnsure your gas stopcock is fully openPress the Reset button (backwards arrow or 'Flame' icon) for five seconds
Protect yourself from future repair bills
A boiler cover plan would cover faults like S.3 — no call-out fees, no surprises.
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Parts commonly replaced
- Ignition Electrode
- Gas Valve
- Flame Sensing Electrode
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