Boiler shows E10 and locks out, often after several failed ignition attempts

Safety first: Turn off power and gas. Repeated ignition failures can lead to unburned gas accumulation; ventilate the area if you smell gas and do not attempt to relight.

• Inspect burner and orifices: Remove the burner assembly per Utica instructions. Check for spider webs, rust, or debris in the burner and orifices. Clean with compressed air and a soft brush; do not use sharp tools that can enlarge orifices.
• Check electrode assembly: Inspect the spark electrode for cracks and proper gap. Refer to the Utica service manual for the correct distance and adjust carefully.
• Verify gas valve connections: Ensure the gas valve coil connectors are firmly attached and not reversed if multiple coils are present.
• Restore and reset: Reassemble the burner, restore gas and power, and reset the boiler. Observe the ignition sequence through the sight glass.
• If lockout recurs: Gas pressure, combustion air, or control timing may be incorrect. Contact a qualified technician for further diagnosis.