The Fasco A173 (NBK part number 12181) is a direct-replacement draft inducer blower motor engineered for Fasco and ICP furnace applications. Running at 3450 RPM on 115 VAC, this permanent split capacitor motor features precision ball bearings for quieter operation and extended service life compared to sleeve-bearing alternatives. If your furnace is throwing a draft inducer fault or the existing motor is noisy, seized, or running hot, this is the drop-in replacement you need.
Draft inducer motors are critical to safe furnace operation -- they evacuate combustion gases before and during the burner cycle, ensuring proper flue draft and triggering the pressure switch that allows ignition to proceed. A failing inducer motor means no heat, and in some cases, a safety lockout that won't reset until the motor is replaced.
The NBK 12181 / Fasco A173 replaces a long list of OEM part numbers across the Fasco and ICP product families, making it one of the most versatile inducer motor replacements in the 3.3-inch frame class. The 34-inch lead with flag terminal connector matches the original wiring harness routing in most applications, so installation is straightforward for anyone comfortable with basic HVAC work.
Precision ball bearings deliver quieter operation and a significantly longer service life than sleeve-bearing motors, especially in high-cycle residential furnace duty.
Integrated thermal overload protection guards the motor windings against overheating, helping prevent secondary damage if airflow is restricted.
Class B winding insulation is rated for continuous operation at elevated temperatures, appropriate for the demanding thermal environment inside a furnace cabinet.
Replaces over 10 OEM and aftermarket part numbers from Fasco, ICP, and Mars, reducing sourcing time and the need to track down obsolete part numbers.
This is a permanent split capacitor (PSC) motor, the standard design for HVAC blower and inducer applications. PSC motors run efficiently at a single fixed speed, draw low starting current, and do not require a start capacitor. The open air-over (OAO) enclosure is designed for applications where the motor is cooled by the airflow it generates -- correct for draft inducer installations where the motor sits in the flue gas stream path or adjacent to it.
This motor is a verified equivalent to the following OEM and aftermarket part numbers. Confirm your existing part number before ordering to ensure correct fit.
Before installing, confirm the motor frame diameter (3.3 inches), rotation direction, and mounting configuration match your existing unit. Draft inducer motors mount in various orientations depending on the furnace cabinet design -- verify flange bolt pattern and shaft orientation against your original motor. Disconnect power and allow the furnace to cool completely before beginning work.