What is the purpose of the 3-inch insertion length

If the HSI ohm reading is infinite

Enhanced Thermal Resistance: High-grade materials designed to resist the thermal cycling common in residential heating systems

Cross-referencing dimensions is not recommended

This OEM condenser fan blade features a 20-inch diameter and a 4-blade configuration with a 28-degree pitch

Reznor 205882 Vent Kit 320788-704 What is the purpose ofThe Reznor 205882 Vent Kit is a critical component for completing a concentric vent installation on high efficiency Reznor CAUA gas fired heaters. Specifically engineered for CAUA 150 and 200 models, this CC6 horizontal vent kit facilitates the proper intake of combustion air while safely exhausting flue gases through a single wall penetration. The 6 inch concentric configuration eliminates the need for multiple holes in the building envelope,