Is your whole house fan not working? The capacitor might need urgent replacing. Here are all 6 known causes & fixes.

Ever since they were invented, whole house fans have become the standard alternative to AC units when it comes to household cooling solutions.

Unless you have any kind of restriction (such as someone living in the attic), there’s virtually no reason to opt against owning one of them. Especially considering the sky-high electric rates these days.

That being said, as wonderful as these machines are, they are not eternal, and will fail over time. Be it due to poor maintenance, or simply from eventual wear and tear, sooner or later, you’ll have to face the music.

When this happens, there are several things that could be to blame, from a broken motor, to a faulty capacitor.

Whatever the case may be, one thing’s for sure, you need to find a way to fix this as soon as possible; however, in order to do it, you need to know exactly what to be looking for.

This is why I’ve prepared the list below, where you’ll find the most common causes to this situation, and the easiest steps you can take to address them. Bear with me, and be patient, I promise we’ll get to the bottom of this.

Fixing a Malfunctioning Whole House Fan

The first thing I want to do is put your mind at ease. Whatever the problem might be with your whole house fan, there is always a very good chance that you can fix it without struggling too much.

More often than not, the malfunction is due to some loose wires, or an insufficiently oiled bearing, both of which can be addressed in the blink of an eye.

Don’t lose hope just yet, we have a lot of work ahead, and several things to try before we throw in the towel.

Here are 6 reasons why your whole house fan might not be working:

  • A broken motor
  • Overheating
  • An insufficiently oiled bearing
  • Loose wires
  • A faulty capacitor
  • A broken thermostat

#1 A Broken Motor

exposed fan motor to be repaired
It’s important to test the motor before buying a new house fan

The first thing I want us to consider is the possibility of a broken motor.

This might come as a surprise to you, but damaging this part is easier than you think. In fact, excessive stress coming from damaged fan blades, loose wires or an insufficiently oiled bearing, can do it in.

If your whole house fan is brand new, we can also consider the possibility of a factory defect, but if it’s not, the problem definitely lies elsewhere.

Solution: In order to fix this, you’ll have to access the unit to replace the motor. Please follow these steps:

  1. Switch off the breakers supplying electricity to the machine
  1. Locate the screws holding the outer panel vent in place, and undo them with a screwdriver
  1. Remove the vent panel
  1. Remove the fan
  1. Locate the motor, and unscrew it carefully
  1. Place it somewhere that allows you to work on it comfortably
  1. Replace it if necessary

It’s important to test the motor before buying a new one, as there could only be minor damage to it.

Provided that it’s a total loss, and you’re a visual person like me, there are tons of online videos you can check out and follow along step by step.

#2 Overheating

This is a household appliance’s worst enemy.

Overheating can happen for a number of reasons, among which the most common ones are fan damage, an overworked motor, and vent obstruction.

As you can imagine, being your whole house fan a temperature regulating machine, making sure that it remains cool enough to operate normally at all times, is essential to preventing any kind of problems from arising.

If your unit is not working, chances are one, or several of its internal components might be struggling to recirculate air properly.

For example, let’s say that your fan blades are damaged. This could create an excessive amount of air resistance while spinning them, which could overwork the motor, and result in high temperatures.

If you combine that with an insufficiently oiled bearing, you have a recipe for disaster.

It is of the utmost importance that prior to operating your machine, you make sure that every single one of its components is in the best possible condition. This will prevent excessive resistances, and proper axis rotation.

Solution:  While there are no general rules as to how often you should check your whole house fan’s components, it’s always a good idea to try and do it at least every couple of months, or as soon as you detect any anomalies.

You can follow the steps from the previous point to gain comfortable access to your machine’s parts for inspection.

#3 An Insufficiently Oiled Bearing

Putting Grease On Motor Fan
Make sure to lubricate the bearing regularly to allow axis rotation

As stated above, while it might seem unimportant, this is a big problem.

Your whole house fan might look like an overly complicated house cooling solution, and while the wiring, and overall electrical setup can be a bit confusing, most of its moving parts, like the bearing, are just like any other you’d find in simpler household appliances.

As you probably know, fans work by making a motor spin blades around a bearing that allows for axis rotation, and air circulation. Being the bearing so essential to the unit’s range of motion, making sure to keep it perfectly well oiled at all times, is vital.

Failing to give this part proper maintenance could result in overheating, and premature motor malfunction, so, if your whole house fan is not working, chances are you might need to stop by the hardware store, and get a new can of motor oil. 

Solution: The exact process will vary from model to model and from manufacturer to manufacturer, but the broad strokes should be the same for all of them.

All you need to do is follow the steps from point #1 to expose the motor and the bearing. Once you have comfortable access to them, you should be able to see a small oil intake where you can pour the lubricant.

Ideally, you want to add this substance to your bearing at least once every two years, but if you detect any malfunctions that could indicate that the part needs to be topped up sooner, please do not hesitate to do so.

#4 Loose Wires

Unless you’re extremely knowledgeable in wiring, and household electrical layouts, chances are you called a certified electrician to install your unit.

While I’m not saying that they did their job incorrectly, there is always room for human error. And even if they did everything correctly, as the unit operates, some wires can break or come loose.

This is not awfully common, but it’s been known to happen.

If your whole house fan is not working, taking a look “under the hood”, and searching for anything abnormal, is a great idea.

Solution: Please follow the steps from point #1 one to gain comfortable access to your unit’s wiring.

Identifying a loose or broken cable should not be too difficult, but having your model’s wiring diagram handy can make things a lot easier for you during the process.

Provided that you find anything that needs to be reattached, you can go ahead and try to do it yourself, but do not hesitate to call a professional if you feel doubtful or unsafe at any point.

Remember, safety first. Always.

#5 A Faulty Capacitor

leaking capacitors
A broken capacitor could be to blame

I’d go as far as to say that this is the lifeblood of your appliance.

A whole house fan with a broken capacitor is like a car with a flooded motor, no matter what you do or try, it won’t start.

As you probably know, this part is solely responsible for controlling your motor, and allowing it to communicate with the fan blades so that they spin and recirculate the air inside your home.

If your whole house fan is not working, and none of the solutions above have worked out for you, there’s a very good chance that this part might need urgent replacing.

Solution: You know the drill. Just follow the steps from point #1 to gain comfortable access to the part, and test it with a multimeter, if you have one.

Remember that, if you get any kind of readings on the meter, the part is fine and the problem lies elsewhere, but if the meter’s screen fails to react when in contact with the capacitor, the component is dead, and needs replacing.

You should be able to purchase a new one either from your nearest hardware store, or directly from your manufacturer. 

#6 A Broken Thermostat

Lastly, let’s take a look at your thermostat.

If you’ve ever had any other temperature-related appliance fail, you definitely know what this part does. If so, please skip down to the solution, but if you’ve never encountered this problem before, let me tell you a little about this component.

Your thermostat is solely responsible for sensing and regulating the temperature inside your unit. It is precisely this part that tells it to shut off automatically when its components are running too hot.

If your whole house fan is not working, there is a very good chance that this part is damaged, thus rendering the unit unresponsive, and unable to activate itself as a safety countermeasure.

Solution: Provided that you’ve tried all the solutions above, you already have comfortable access to all your machine’s internal components, so all you need to do now is locate the thermostat, and test it for continuity with your multimeter.

When Should You Call a Pro?

The answer to this question will vary from person to person.

If your warranty is still active, and don’t mind waiting a couple of days or weeks to have your manufacturer send in a technician to look at the appliance, by all means, go ahead and call them.

Unless otherwise specified, they should fix it for you at no cost.

Provided that you’re no longer under coverage, but feel capable enough to try and do your own repairs, knock yourself out, you’ll save some money, and a considerable amount of time.

Having said that, there’s no shame in asking for help.

Sure, calling a professional when your warranty has expired will cost you some money, but you can’t put a price of your safety. If you ever feel unsafe or doubtful during the DIY process, please stop, and let the technicians work.

Conclusion

To have your whole house fan stop working can be very inconvenient. Especially if it happens during a very hot season.

Luckily, as you’ve learned on this piece, there’s a very good chance that all you need to do in order to get the unit back to normal, is oil your fan bearing regularly, check your blades for damage, and look for any loose or broken wires that need reattaching.

Remember, continuous and adequate maintenance to your appliance will keep it working perfectly, and extend its lifespan significantly.

Thank you for reading. If you found this article useful, why not expand your knowledge further through our other incredible resources below?

Stay cool!