Furnace shows E16; unit may lock out after multiple failed ignition attempts

Safety first: Turn off power and gas before working on ignition or gas components.

• Reset lockout: Turn off power to the furnace for 30 seconds, then restore. This clears the lockout so you can observe the ignition sequence.
• Observe sequence: Watch through the sight glass: inducer starts, ignitor glows, gas valve clicks, burners light. Note at which step failure occurs.
• Check ignitor: If the ignitor never glows, test it for continuity. An open ignitor must be replaced with the correct Napoleon part.
• Check gas valve operation: If the ignitor glows but there is no gas sound or flame, the gas valve may not be opening. Verify 24V is sent to the gas valve during ignition. If voltage is present but no gas, the valve is faulty and must be replaced by a professional.
• Gas pressure: Incorrect gas pressure requires a manometer and should be checked and adjusted only by a licensed technician following Napoleon specifications.