F56 – A56 High
Your boiler is having trouble setting up its gas and air mixture correctly, which prevents it from firing up safely.
Technical description: Calibration error / calibration procedure not completed
Typical repair cost: £100-350 (including labour)
DIY fix possible
Check that your gas supply is turned on and other gas appliances are workingPress and hold the 'Reset' button for 5 seconds to clear the faultAllow the boiler to attempt its automatic calibration sequence for several minutes
Protect yourself from future repair bills
A boiler cover plan would cover faults like F56 – A56 — no call-out fees, no surprises.
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Parts commonly replaced
- Gas valve
- Ionisation electrode
- PCB (Control board)
*Affiliate links — we may earn a commission at no extra cost to you.