E4 High
Your boiler is struggling to light and stay on, which can sometimes be caused by trapped air in your heating system preventing the water from flowing correctly.
Technical description: Ignition failure – try bleeding your radiators
Typical repair cost: £90-280 (including labour)
DIY fix possible
Turn off the boiler and wait for the radiators to cool downUse a radiator key to bleed any air from all radiators in the houseCheck the boiler pressure gauge and top it up to 1.5 bar if it has droppedPress the 'Reset' button on the boiler control panel
Protect yourself from future repair bills
A boiler cover plan would cover faults like E4 — no call-out fees, no surprises.
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Parts commonly replaced
- Ignition electrode
- Flame sensing probe
- Gas valve
- Spark generator
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