Inducer Orifice Selection Guide for Nortek Gas Furnaces

Important Information

This document provides the necessary technical data to select the correct inducer orifice size for specific Nortek gas furnace models. It is intended for use by qualified technicians during the installation or replacement of the inducer assembly. Always verify the orifice size by checking the physical marking on the back side of the component.

Selecting the Correct Orifice

To ensure proper furnace operation, you must select the orifice size that matches your specific furnace configuration. Follow these steps:

• Identify your furnace model series (*G7, *PGC2, M7RL, M7TL, or MG2S).
• Locate the corresponding table for your model series.
• Identify your furnace's Cabinet Size.
• Match the Cabinet Size with the Input (MBTUH) rating of your unit.
• Select the corresponding Orifice Size (in inches) from the table.

Reference Tables

The document contains specific selection tables for the following furnace series:

• *G7, *PGC2 Upflow / Horizontal Units: Provides orifice sizes for various cabinet sizes (A, B, C, D) and input ratings.
• *G7 Downflow Units: Provides specific orifice sizes for downflow configurations.
• M7RL & M7TL Downflow Gas Furnaces: Provides orifice sizes for cabinet sizes A and B.
• MG2S Downflow Gas Furnace: Provides orifice sizes based on orientation (Front or Top) and input ratings.