Electronic gas water heater displays E16; unit may not start or may shut down with a combustion-related fault.

Safety: Turn off power and gas before inspecting intake piping.

• 1. Inspect intake termination: Locate the combustion air intake termination outside. Remove any screens or covers and clean out leaves, insects, or snow.
• 2. Check intake piping: Follow the intake pipe back to the heater, looking for sags, low spots with water, or crushed sections. Correct any issues and ensure proper slope.
• 3. Clean internal screens: Some models have internal intake screens at the blower or combustion chamber. Remove and clean these screens if accessible.
• 4. Test air proving switch: If the model uses a dedicated air proving switch, inspect tubing and test switch continuity when the blower runs. Replace if it does not close properly.
• 5. Reset and test: After clearing blockages and verifying components, reset the control and test operation while monitoring for stable combustion.