Boiler locked out, red fault lamp on, no heating or hot water

Safety first: Turn off electrical power to the boiler at the isolator and close the gas isolation valve before removing any covers. Only a Gas Safe / licensed gas technician should work on gas components.

• Check gas supply: Verify other gas appliances work. Ensure the boiler’s gas isolation valve is fully open. If there is no gas to the property, contact your gas supplier.
• Reset the boiler: Restore power, then use the Nibe control panel to perform a reset (refer to the user menu, usually by pressing and holding the reset/OK button). Observe if the boiler attempts ignition.
• Inspect flue and air intake: From outside, check that the concentric flue terminal is not blocked by debris, snow, or nests. Clear any obstruction without dismantling the flue.
• Check ignition noise: During start-up, listen for the clicking of the ignition electrode. If there is no clicking, the ignition module or electrode may be faulty and requires a technician.
• Call a professional: If E01 persists after reset and basic checks, a qualified Nibe technician must test the gas valve, ignition electrode, and flame sensor with proper instruments and replace faulty parts.