Furnace Blower Assembly Maintenance Guide

9 February 2021
 Categories: , Blog

The furnace blower motor is the heart of your heating system. The motor is what powers the fan, which is responsible for moving the heated air all throughout your home. Having a basic understanding of the motor and how to maintain it can help prevent unnecessary breakdowns.

Blower Motor Basics

The blower motor assembly is made of a few key components that do not vary greatly between furnace models. It begins with the motor itself, which turns the shaft. The shaft is then hooked up to a belt attached to the fan, or the shaft is directly attached to the fan, depending on your furnace model.

Inside the motor and shaft are moving parts that contain bearings, which are there to ensure minimal friction and smooth movement. Electrical capacitors and switches are also present to control the flow of power depending on the furnace settings. The entire assembly is inside a housing that protects the motor assembly from dust and damage.

Common Points of Failure

There are a few common points of failure in a blower. The most common is friction damage, usually from failed bearings. If the bearings fail, the motor can seize up and the fan will stop moving. Friction can also be a result of poor lubrication, an unbalanced fan blade, or dust in the assembly.

Another common point of failure is a worn or broken belt since the shaft can't move the fan in belt-driven furnaces without it. Electrical problems can also affect the blower motor. A failed capacitor or an electrical short can stop the motor completely. Sometimes the motor may also grind to a halt due to overheating, which can be caused by friction, overuse, or electrical shorts.

Preventative Maintenance Tasks

Fortunately, a bit of preventative maintenance goes a long way toward preventing most blower assembly issues. Your furnace should be tuned up once a year, either right before the onset of the heating season or in spring when you power down the furnace for the season. It's also important to replace the air filter every one to two months so dust doesn't collect inside the blower.

A technician will open up the unit and completely dust out the assembly. They will then inspect and replace the belt if needed. The bearings and other moving parts are lubricated, and the electrical system is fully inspected and repaired if necessary. The final task is ensuring the fan is clean and balanced properly.

Contact a heating service contractor for more help with repairing on maintaining your furnace blower.