Boiler will not ignite; display shows E01 shortly after a call for heat or domestic hot water.

Safety first: Turn off power to the boiler at the service switch and close the gas shutoff valve before removing any covers. If you ever smell gas, evacuate and contact your gas supplier or emergency services.

• Check gas supply: Verify the manual gas shutoff valve to the IBC boiler is fully open. Confirm other gas appliances in the home work. If no gas, contact your gas provider.
• Reset the boiler: Restore power and follow the IBC control panel instructions to reset the lockout. Observe if the boiler attempts ignition (you should hear the fan, then clicking from the igniter).
• Inspect ignition electrode and cable: With power off and front panel removed, locate the ignition electrode assembly on the burner. Check for cracked porcelain, heavy carbon buildup, or a loose/high‑resistance ignition cable connection at the ignition transformer/board. Clean light deposits with a non‑metallic abrasive pad and re‑seat the cable firmly.
• Check flame sensor: Many IBC models use a combined ignition/flame rod; others have a separate flame sensor. Remove and gently clean the rod with fine emery cloth to remove oxidation. Reinstall ensuring proper insertion depth and alignment per the service manual.
• Verify gas valve wiring: Confirm the harness to the IBC gas valve is fully seated and not damaged. Do not attempt to adjust gas valve settings without combustion test equipment.

If E01 persists after these checks, a licensed gas technician should test gas pressure, ignition voltage, and combustion, and replace the gas valve or ignition components as needed.