Boiler will not ignite, display shows E01, no flame symbol, heating and hot water not working

Safety first: If you smell gas, do not attempt any repair. Turn off the gas at the emergency control valve, switch off power to the boiler, ventilate the area, and contact your gas supplier or a Gas Safe registered engineer immediately.

Basic user checks (no tools):

• Press the reset button once (refer to your Baxi manual for location). Wait a full ignition cycle (1–2 minutes) to see if the boiler lights.
• Check that the gas supply is on: other gas appliances (hob, fire) should work normally.
• Ensure the boiler gas isolation valve under the boiler is fully open (handle in line with the pipe).
• Confirm system pressure is around 1.0–1.5 bar when cold. If low, top up via the filling loop as per the Baxi instructions.

Visual inspection (power off):

• Isolate electrical power and allow the boiler to cool.
• Remove the front case only if your model’s case is user-removable (many Baxi boilers have a room-sealed combustion chamber that must only be opened by a Gas Safe engineer).
• Look through the inspection window (if fitted) for signs of soot, debris, or corrosion on the burner area.

When to call a professional:

• If E01 returns after a single reset.
• If the burner does not light at all or lights then goes out within a few seconds.
• Any work on the gas valve, burner, ignition electrode, or flame sensor must be carried out by a Gas Safe registered engineer. They will clean or replace the ignition/flame sensing electrodes, check the burner, verify gas pressures, and test the gas valve operation.