The Case For Pulling The Blower Housing


When I started in the trade in 1999, there were still many oilable blower motors in service. As part of the maintenance, we would remove the housing and oil the motor. We would also vacuum the motor and wipe it down.

As oilable motors have become extinct, I see fewer and fewer techs pulling the blower housing. Here are some reasons you may want to consider doing it more often:

  • Cleaning the motor itself can help it run cooler and last longer. A hot motor is not only more susceptible to winding breakdown but also to bearing/lubricant failure. Grab a vacuum, soft bristle brush, and a rag and get the dust buildup off the motor. If you have any dust that gets stuck inside, use some low-pressure nitrogen or compressed air to get it clean.
  • Get in there and look carefully at the wheel. A wheel that is even slightly dirty can have a significant effect on air output. If it's dirty,  recommend cleaning.
  • Check the blower bearings; it's easier to do when the motor is out.
  • In high-efficiency furnaces, pulling the blower is a good way to check the secondary heat exchanger. On 80% furnaces, you can check parts of the primary exchanger and even the evaporator coil with a mirror or inspection scope.
  • Pulling the blower gives you the ability to wipe down the inside of the furnace or fan coil.
  • You can check blower mounting bolts, set screws, and blower alignment. You can also balance more easily.

Obviously, when and why you pull the housing will vary from contractor to contractor, but I advocate it being done more often than it is now.

What say you?

—Bryan

3 responses to “The Case For Pulling The Blower Housing”

  1. Excellent! I agree that this practice should be more common. I also thank you for the idea of using my nitrogen instead of compressed air to blow out the motor, as the compressed air often contains considerable amounts of moisture, which can be concerning in itself. Thanks Bryan!

  2. Love this article.

    So, those “self oiling motors” have that little felt pad in there….on condenser fan motors, I flip it over and oil the shaft area while cleaning out the leaves and debris from condenser. I will start using my spout oiler in blower too. As far as pulling it out, great idea, especially on those Spring maintenances that come from new customers that obviously called for a maintenance because their AC isn’t performing.

    I’ve sold a lot of cleanings by using my flashlight ( a high quality light, not a throw away or worse, cell phone light) inside the AHU pointing out all the dirt, etc. ignored by previous techs.

  3. Pulling the blower on a blocked condensate drain call or low cooling call can allow one to look up into the bottom evaporator coil for cleanliness and to see if blocked condensate poured over the pan and onto the blower and housing.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Related Tech Tips

How Moisture Moves
Old-timers always used to say that running plumbing and condensate drains wasn't rocket science because “water flows downhill.” While that may be true, water also floats in the air, goes uphill, and forces its way through concrete. Here is a look at some of the ways that water moves that impact building comfort and integrity. […]
Read more
Can Pulling a Vacuum too Fast Freeze Water/Moisture?
First, I want to give credit where credit is due. This post is made possible by the fantastic demonstration video by Neil Comparetto that I embedded below. Before you get bored and stop reading, I want to get the conclusion out in the air. Ice can form in a vacuum, but I still advise pulling a […]
Read more
Static Pressure - Why Measure It?
This article was written by Neil Comparetto. Neil is one of the smartest and most thoughtful techs I know online. Thanks, Neil. Why measure static pressure? Because it's fun. I enjoy drilling holes in things. I rarely leave a house without drilling a hole in something. I also believe it’s an essential step to commissioning […]
Read more
loading

To continue you need to agree to our terms.

The HVAC School site, podcast and daily tech tips
Made possible by Generous support from