In the case where two or more vent connectors enter a common gas vent, which connector should enter at the highest level?

In systems where multiple vent connectors discharge into a common gas vent, it's essential for operational safety and efficiency that the smaller connector enters at the highest level. This configuration helps to prevent the potential for backdrafts or flue gas leakage, ensuring that the gases being vented can rise and exit effectively.

When smaller connectors are positioned above larger ones, it minimizes the risk of carbon monoxide and other hazardous gases settling back into the appliance, which could lead to health risks or system malfunctions. Proper venting ensures that flue gases rise and flow in the direction intended, facilitating a safer environment. This arrangement aligns with best practices and building codes related to gas venting installations in residential and commercial settings.