Furnace display shows E16, unit may lock out with an intake/exhaust configuration error after installation or venting changes.

Safety first: Turn off power and gas. Venting errors can lead to carbon monoxide hazards.

• 1. Verify vent configuration: Compare the actual intake and exhaust piping to the Thermia installation manual for your model. Confirm correct pipe size, maximum length, and number of elbows.
• 2. Check intake/exhaust connections: Ensure the intake is connected to the combustion air port and the exhaust to the flue outlet on the Thermia furnace. They must not be reversed.
• 3. Inspect terminations: Outside, confirm that the intake and exhaust terminations are properly spaced and oriented per Thermia guidelines.
• 4. Review control board settings: Some Thermia models require configuration (dip switches or menu settings) for one-pipe vs two-pipe operation. Verify these match the installed venting.
• 5. Professional verification: Have a qualified technician perform combustion analysis and confirm safe operation after correcting any venting issues.