The Case For Pulling The Blower Housing


When I started in the trade in 1999 there were still a lot of oilable blower motors in service. As part of the maintenance we would remove the housing, oil the motor plus vacuum / 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 not only is 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 it’s out
  • On 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 and set screws as well as blower alignment and 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

2 comments

  1. D. Baker says:

    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. Bill says:

    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.

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