2 - Primary heat exchanger

3 - Power vent fan

4 - Adaptive hot surface silicon carbide igniter (TUC/TDC models only)

5 - Multi-port in-shot burners

6 - Self-diagnostic controls

7 - AL-29-4C stainless steel secondary heat exchanger

8 - Internal vent pipe

9 - Multi-speed power blower motor

10 - Cleanable filter