Boiler displays E0 and will not start heating or hot water

Safety first: Turn off electrical power to the boiler and close the gas isolation valve before removing any covers. Only a Gas Safe (or equivalent) registered engineer should work on gas components.

• Reset the boiler: Press the reset button as per the Remeha manual and wait a full cycle. If E0 returns, continue.
• Check gas supply: Ensure other gas appliances work. Verify the gas isolation valve under the boiler is fully open. If there is no gas to the property, contact your gas supplier.
• Inspect flue terminal: From outside, make sure the flue is not blocked by debris, snow, or vegetation, which can affect combustion.
• Check ignition/ionisation leads (visual only): With power off and front case removed by a competent person, visually inspect the ignition and ionisation electrodes and cables for cracks, burns, or loose connections. Do not bend or file electrodes.
• Engineer tasks: A qualified engineer should test the ionisation current, check and adjust gas valve settings, clean or replace the ignition and ionisation electrodes, and verify correct combustion using a flue gas analyser.