Boiler shows E1 and will not ignite; fan may run briefly then shut down.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Turn off power and gas to the boiler. Do not attempt ignition troubleshooting if you smell gas in the room—evacuate and call your gas supplier or emergency services.
- Step 1 – Verify gas supply: Confirm the manual gas shutoff valve to the boiler is fully open. Check that other gas appliances in the home are working. If none work, contact your gas supplier.
- Step 2 – Inspect flame sensor: Remove the burner access panel. Locate the flame sensor rod near the burner. With power OFF, remove the sensor and gently clean it with fine steel wool or a Scotch-Brite pad to remove oxidation. Reinstall and ensure the wiring connection is tight.
- Step 3 – Check igniter: For hot surface igniters, visually inspect for cracks or breaks. For spark igniters, check that the electrode is not cracked and that the spark gap is not bridged by debris. Do not touch the element with bare fingers. If damaged, the igniter must be replaced.
- Step 4 – Confirm proper grounding: Ensure the boiler chassis is properly grounded and that the ground wire to the control board is secure. Poor grounding can cause ignition sensing issues.
- Step 5 – Reset lockout: Restore power and follow the manufacturer’s reset procedure (often cycling power or pressing a reset button on the control). If E1 returns after several attempts, the gas valve or control board may be faulty and should be diagnosed by a professional.
Warning: Do not repeatedly reset a boiler that fails to ignite; unburned gas can accumulate and create an explosion hazard.