Furnace fails to ignite, burner does not light, display shows E01 shortly after a heating demand.

Safety first: Turn off electrical power to the furnace and close the gas isolation valve before removing any covers. Wait for all components to cool.

• Check gas supply: Verify that the gas isolation valve to the Chaffoteaux furnace is fully open and that other gas appliances in the home work correctly. If there is no gas supply, contact your gas provider.
• Inspect the burner area: Remove the front casing and sealed combustion chamber cover (if accessible). Look for soot, rust, or debris on the main burner and around the ignition electrode. Gently clean with a soft brush and vacuum, avoiding damage to the burner ports.
• Check ignition electrode and cable: Inspect the ignition electrode on the burner assembly for cracks, heavy scaling, or damage. Ensure the ceramic insulator is intact and the electrode tip is 3–4 mm from the burner surface (refer to the Chaffoteaux service manual for your exact model). Make sure the ignition cable is firmly connected to the ignition transformer on the control board.
• Flame detection electrode: On many Chaffoteaux furnaces the same electrode or a nearby rod is used for flame sensing. Clean the electrode tip with fine emery cloth and wipe with a dry cloth. Ensure the sensing lead is firmly connected to the control board.
• Reset the appliance: Restore power and gas, then press the reset button (or follow the reset procedure in the user manual). If E01 reappears after several attempts, stop trying and contact a qualified Chaffoteaux technician, as the gas valve or control board may be faulty.

Do not attempt to adjust gas valve settings or burner pressure without proper training and calibrated instruments.