Furnace fails to ignite, display shows 01 shortly after a call for heat

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 Vokera furnace is fully open and that other gas appliances in the home work normally. If gas supply is suspect, contact your gas supplier.
• Inspect the burner area: Remove the front panel and combustion chamber cover (on sealed models). Look for soot, rust flakes, or debris on the main burner and around the ignition electrode. Gently vacuum loose debris and clean metal surfaces with a soft brush.
• Clean ignition electrode and flame sensor: Locate the ignition/flame sensing electrode assembly near the burner. Carefully remove the electrode (note position first). Lightly clean the ceramic and metal tip with fine emery cloth or a non-abrasive pad. Do not bend the electrode. Refit and ensure the gap to the burner is as per the service label.
• Check wiring connections: Inspect the ignition lead from the PCB to the electrode for cracks, burn marks, or loose terminals. Reseat connectors on the main PCB and at the electrode.
• Reset the furnace: Restore power and gas, then follow the Vokera user instructions to reset the appliance. Call for heat and observe ignition. If code 01 reappears, further testing of gas valve pressure and PCB output is required by a qualified technician.

Do not attempt to adjust gas valve settings or work on sealed combustion components unless you are a licensed gas engineer.