Boiler shows E1 and will not ignite; burner never lights and you may hear only a brief click

Safety first: Turn off power and close the manual gas shutoff valve before removing burner or gas components. Do not attempt repairs if you smell strong gas—evacuate and call your gas supplier.

• Confirm gas supply: Make sure the 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 utility.
• Reset the boiler: Turn power off for 30 seconds, then back on. Attempt a call for heat. If E1 reappears after several tries, continue.
• Inspect the igniter: Remove the burner access panel. Locate the hot surface or spark igniter. Look for cracks, heavy white deposits, or broken wiring. A cracked or heavily scaled igniter should be replaced.
• Clean the flame sensor: If the flame sensor is separate from the igniter, gently clean the metal rod with fine emery cloth or a Scotch‑Brite pad to remove oxidation. Do not sand aggressively.
• Check burner area: Ensure the burner and orifices are not blocked by rust, debris, or insect nests. Lightly vacuum around the burner (do not alter orifices).
• If ignition still fails: Gas pressure, combustion setup, and ignition timing must be checked with proper instruments. Contact a qualified boiler technician.