Water heater will not ignite; no hot water. Error 111 displayed on Takagi controller.

Safety first: Turn OFF gas at the manual shutoff valve and switch OFF electrical power before removing covers. Allow the unit to cool completely. If you ever smell gas, stop and contact your gas supplier or a licensed technician immediately.

Step-by-step checks:

• 1. Verify gas supply: Ensure the gas shutoff valve to the Takagi unit is fully open. Confirm other gas appliances in the home work normally. If other appliances are weak or not working, you may have a supply or regulator issue that requires a professional.
• 2. Reset the unit: Turn power OFF for 30 seconds, then ON. Attempt to run hot water again and see if error 111 reappears.
• 3. Inspect and clean igniter: Remove the front cover. Locate the igniter assembly near the burner. Check for cracks, heavy carbon buildup, or loose connections. Gently clean the igniter tip with fine emery cloth or a soft brush. Ensure the gap and position match the service manual specifications.
• 4. Check flame rod (flame sensor): The flame rod is usually next to the burner. Remove and clean the rod with fine steel wool or emery cloth to remove oxidation. Reinstall firmly and ensure the wire connection is tight.
• 5. Check burner area: Inspect the burner surface for dust, lint, or debris. Vacuum gently with a soft brush attachment. Do not bend or damage burner ports.
• 6. Restore power and gas: Turn gas and power back ON and test with a hot water demand. If error 111 persists after cleaning and confirming gas supply, the igniter assembly, flame rod, or gas valve may need replacement and should be diagnosed by a qualified technician.