State Water Heater E111 Error Code — What It Means
E111 on a State tankless water heater is a flame failure or ignition failure code. The unit called for heat and energized its ignition system, but it did not detect flame or lost flame during the startup sequence. This is an ignition problem, not a water temperature sensor issue. State tankless heaters are part of the A. O. Smith family, and service references for that platform consistently define code 111 as a flame or ignition failure rather than any other condition.
Common Causes
- Low gas supply or delivery problem Gas shutoff valve closed or partially closed, undersized gas piping, low inlet pressure, or air trapped in the gas line after a new installation.
- Blocked air intake or vent restriction Lint, debris, or other material blocking the combustion air intake screen or exhaust vent, preventing proper airflow for ignition.
- Ignition system fault Weak or failed ignition transformer, poor wiring connection, or failing control board output that cannot generate spark.
- Flame detection component dirty or failing Contamination on the flame-sensing rod or poor grounding that prevents the control from proving flame even when combustion is present.
- Insufficient water flow Clogged inlet screen or filter restricting flow below the minimum needed to trigger the ignition sequence.
- Combustion chamber contamination Lint buildup, dust, or scale on burner surfaces interfering with ignition or flame stability.
Step-by-Step Fix
- Note the code and reset the unit by turning off power or gas, waiting 30 seconds, then restoring it. Open a hot water tap and see if the code returns during the next call for heat.
- Check that the gas shutoff valve is fully open and that other gas appliances in the home are working. If the heater is newly installed, purge the gas line to remove trapped air.
- Inspect the air intake and exhaust venting for any blockage, lint, or debris. Remove and clean the intake screen or filter if accessible, and confirm that vent terminations outside are clear.
- Verify water flow and clean the inlet filter. Locate the cold-water inlet screen or filter on the unit, remove it, rinse under running water, and reinstall.
- Inspect the ignition and flame-sensing components inside the combustion chamber if you are comfortable opening the unit. Look for contamination, corrosion, or loose wiring on the igniter, flame rod, and burner assembly. Clean gently with a soft brush or cloth if dirty.
- Measure gas pressure during a call for heat if you have a manometer. One field example showed inlet pressure around 6.7 inches water column during troubleshooting, but consult your model’s installation manual for the correct static and dynamic pressure specifications.
- Test the ignition transformer and flame-proving circuit with a multimeter if the unit still fails to ignite. Replace the ignition transformer, gas valve, flame rod, or control board as needed based on test results. Reassemble, reset, and run multiple hot-water draws to confirm stable ignition.
Parts Often Needed
| Part | Notes |
|---|---|
| Ignition transformer / igniter assembly | Amazon | Match your State model number; often sold as a single assembly with wiring. |
| Flame-sensing rod | Amazon | Verify compatibility with your heater’s control board and burner configuration. |
| Gas valve | Amazon | Use the exact replacement valve specified in your model’s parts diagram. |
| Air intake filter or screen | Amazon | OEM part for your model; generic screens may not seal correctly. |
When to Call a Pro
Call a licensed plumber or gas technician if you are not comfortable working with gas connections, electrical components, or opening the combustion chamber. If you have verified that gas is flowing, the intake is clear, and the inlet filter is clean but the code persists, the fault is likely in the ignition transformer, gas valve, flame sensor, or control board. These components require multimeter testing, gas pressure measurement, and safe disassembly. A technician will also check proper venting, gas pipe sizing, and grounding, all of which affect ignition reliability and safety.