Burner does not ignite, furnace attempts start then locks out with A01 on display

Safety first: Turn off the main power switch to the Brötje furnace and close the gas shutoff valve before removing any covers. Wait several minutes for any unburned gas to dissipate. Only qualified personnel should work on gas-carrying components.

Step-by-step checks:

• 1. Reset the boiler: Press the reset button on the Brötje control panel (refer to your model’s manual). If A01 reappears after 2–3 attempts, continue with diagnostics.
• 2. Check gas supply: Ensure the external gas shutoff cock is fully open. Verify that other gas appliances in the building work. If there is no gas or suspected low pressure, contact your gas supplier.
• 3. Inspect ionisation electrode: Remove the burner cover. Locate the ionisation electrode on the Brötje burner assembly. Check for cracks in the ceramic, heavy soot, or corrosion. Clean the electrode tip gently with fine emery cloth and wipe with a dry cloth. Ensure the electrode cable is firmly seated on the control board and not damaged.
• 4. Check ignition transformer and cable: Inspect the high-voltage ignition cable for burn marks, cuts, or loose connections at the ignition transformer and electrode. Replace if insulation is brittle or cracked. Listen for sparking during ignition attempt (with cover in place and observing through inspection window).
• 5. Verify gas valve operation: With a manometer and appropriate training, check that the Brötje gas valve receives power during ignition and that inlet and outlet pressures are within specification. If the valve does not open or is stuck, it must be replaced by a qualified technician.
• 6. Check burner and mixing tube: Remove and clean the premix burner surface and mixing tube if clogged with dust or debris, which can prevent stable ignition.

When to stop: If you smell gas continuously, see signs of overheating, or are not trained to work on gas valves and combustion components, stop and call an authorised Brötje service technician.