An appliance vented by natural draft should not connect to a vent chimney on what side of the mechanical flue exhauster?

Connecting an appliance vented by natural draft to the vent chimney on the discharge side of a mechanical flue exhauster is not permissible because it can create conditions that are unsafe or inefficient for venting. The discharge side of a flue exhauster is where the positive pressure is created to push exhaust gases out of the system. This pressure could lead to backdrafting, where combustion gases from the appliance are pushed back into the appliance or building, instead of venting outside. This could pose serious safety hazards, including the risk of carbon monoxide entering the occupied space.

In contrast, the venting system is designed to ensure that the natural draft operates correctly. Appropriately connecting a natural draft system to the intake side allows for proper airflow and venting, ensuring that combustion gases are expelled safely and effectively. Thus, understanding where to connect the appliance vent in relation to the mechanical flue exhauster is crucial for safe and proper venting practices in accordance with the International Mechanical Code.