Unit will not ignite; display shows Code 11 shortly after a demand for hot water

Safety first: If you smell gas, do not attempt to light the appliance. Evacuate and call your gas supplier or emergency services. Otherwise, turn OFF power and gas before opening the unit.

Steps to check:

• Confirm gas is ON: Verify the manual gas shutoff valve near the heater is fully open. Check that other gas appliances work.
• Bleed air from gas line (by technician preferred): After gas service, air in the line can cause Code 11. Running the unit several times may purge air, but repeated failures should be handled by a technician.
• Inspect igniter and wiring: With power off, remove the front cover and check the igniter for damage and secure wiring connections.
• Check electrical ground: Ensure the unit is properly grounded at the power connection; a poor ground can affect ignition sensing.

When to call a professional: If Code 11 persists, a licensed technician should measure gas pressure, test the igniter, and verify operation of the gas valve and control board.