Boiler does not ignite, display shows A01 lockout, red fault LED lit

Safety first: Turn the boiler off at the control panel and isolate electrical power at the breaker. Close the gas isolation valve before removing any covers. Only a qualified gas engineer should work on gas-carrying components.

• Check gas supply: Verify that the gas isolation valve under the boiler is fully open and that other gas appliances in the property work. If there is no gas to any appliance, contact your gas supplier.
• Reset the boiler: After confirming gas supply, press the reset button as per the Wolf manual (usually hold for a few seconds). Observe whether the boiler attempts ignition (you may hear clicking).
• Inspect flue terminal: From outside, ensure the flue is not blocked by debris, snow, or nests, which can affect combustion and flame stability.
• Check ignition cable (visual only): With power isolated and front cover removed by a competent person, visually inspect the ignition electrode lead for obvious damage, burning, or disconnection. Do not adjust gas valve settings.
• Call a qualified technician if A01 persists: They will test the ignition electrode, ionisation electrode, gas valve coil resistance, and verify correct gas pressure and combustion using a flue gas analyser.