A vent connector must be installed without any dips or sags and should slope upward at least:

The requirement for a vent connector to slope upward is crucial for ensuring that combustion gases can effectively escape the appliance and do not become trapped within the venting system. When a vent connector is installed with an upward slope, it promotes proper drainage of condensate and prevents the buildup of moisture which could lead to corrosion or blockage.

A slope of 1/4 inch per foot is the standard recommendation for vent connectors, as it provides a reliable angle for facilitating the flow of gases while maintaining optimal performance. This slope helps to ensure that any condensate resulting from the combustion process can flow back toward the appliance rather than accumulating in the vent, which could potentially create safety hazards.

The other choices do involve slight slopes, but they do not meet the typical industry standard for vent connectors. A slope of 1/8 inch per foot may not provide sufficient upward slope to effectively prevent moisture accumulation, while a 1/2 inch per foot might be excessive and could complicate installation without providing additional benefits. Additionally, an indication that upward slope isn’t necessary contradicts the established safety and performance guidelines that are necessary for proper vent installation.