Preventing Blower Fan Burnout: Causes, Replacement Tips (2024)

How to Prevent Blower Fan Burnout: Causes, Prevention, Replacement Costs, and More

If you suddenly find yourself feeling a chill despite the fact that your furnace is running, or can’t ignore the loud rattling sound coming from your vents, it could be that you have a problem with your blower fan. One of the more common issues with a furnace blower fan is burnout. While it might be an uncomfortable inconvenience, it usually isn’t anything too serious and can be resolved quite easily with just a little bit of know-how.

What Is Blower Fan Blowout?

Blower fan blowout is a problem that occurs when the blower fan in your home’s furnace stops working. The fan will stop circulating the air throughout your HVAC system. It most commonly occurs when the blower fan motor becomes aged or is overworked. A lack of regular maintenance is generally to blame for blower fan burnout.

What Causes Blower Fan Burnout?

There are several things that could cause a blower fan to burn out, and most of them are related to wear and tear on the component. Causes of blower fan burnout include:

  • Windings that have deteriorated.
  • Bearings that have seized after running out of oil.
  • Extreme static pressure.
  • A clogged filter, which fails to remove dust before it makes its way to the blower.
  • Inadequate air flow within the system.
  • Buildup of dust, dirt, or debris.
  • Electrical problems, including an excessive voltage supply.
  • Motor insulation failing prematurely due to high temperatures.
  • A weak blower capacitor.
  • The blower fan motor is too small for the unit. (This happens when the motor is repaired with an incorrect replacement.)
  • The air temperature within the furnace is too hot.

Some commonly occurring signs that you have a problem with your blower fan are that there is no air coming out of the registers even though the system is running, there is a loud rattling noise, and there is a burning-type smell within the system.

How Can I Prevent Blower Fan Burnout?

As with most other furnace issues, one of the best ways to prevent blower fan burnout is to schedule and perform regular cleanings of your HVAC system. As the old adage goes, an ounce of prevention really is worth a pound of cure. Scheduling regular cleanings can help homeowners avoid a costly repair bill. By reducing that amount of dirt and dust within your system, you will reduce the potential for buildup within the blower and thus reduce the strain on the motor. This helps to ensure that your system will be running in tip top shape for many years to come.

Simple tasks that homeowners can take to maintain their blower fan include:

  • Regularly changing/cleaning the furnace air filter.
  • Ensuring the area around the fresh air intake vent is kept free of dirt and dust.
  • Regularly vacuuming around their furnace.
  • Regularly vacuuming registers.
  • Cleaning the blower fan.
  • Making seasonal or annual cleanings and maintenance by a qualified HVAC professional part of the home maintenance schedule.

If you are ever unsure or uncomfortable performing any of these tasks, contact a qualified HVAC professional to assist you.

How Much Does It Cost to Repair a Blower Fan?

If your blower fan has failed and you need to replace it, the cost varies depending on the make and model of your furnace, as well your location. Other factors that may affect pricing include time of year and experience of the professional you call.

How you fix a burned out blower fan depends on the root cause. For example, if it’s simply a matter of dust buildup or a lack of oil, regular cleaning and maintenance should do the trick. Conversely, if the issue is electrical, fixing that system should resolve fan burnout issues. However, if there is a more complex or critical problem with the blower fan or the motor, you may need to replace your furnace. Since blower fan burnout can lead to cascading problems with other components in the HVAC system, it’s best to address any issues as soon as they occur.

Depending on the age of your HVAC system, it might make more sense to replace the furnace than to repair the blower fan or blower fan motor. This is especially true if you’ve had to make multiple repairs in a short period of time. A qualified HVAC professional can help you make this assessment.

Preventing Blower Fan Burnout: Causes, Replacement Tips (2024)

FAQs

What causes a blower motor to burn out? ›

It most commonly occurs when the blower fan motor becomes aged or is overworked. A lack of regular maintenance is generally to blame for blower fan burnout.

What causes the blower motor resistor to go out? ›

They fail on their own quite often. Repeated failures are typically caused by excessive current draw from the blower motor (usually caused by tight bearings), or restricted airflow past the resistor causing overheating (plugged cabin air filter, dirty heater core or A/C evaporator).

Why do fan motors burn out? ›

Overheating is the most common cause of motor failure. Overheating damages the insulation protecting the motor windings allowing it to "short out." A 20-degree temperature increase beyond the rated temperature rise can reduce the insulation's effectiveness by 50%.

What causes a blower motor to speed up and slow down? ›

It could a voltage issue. Voltage or hertz fluctuation, or a grounding problem. Another issue could be a problem with the fan motor or control. The wiring to the air conditioner is inadequate to carry sufficient amperage.

What are the main factors that can cause a blowers to fail and why? ›

Factors That Lead to Failure of Vacuum Blowers
  • Over-Temperature Damage. It's normal procedure to replace ball bearings in blowers every few years. ...
  • Ignoring Filter Maintenance. Foreign materials making their way into your blower can also lead to failure of the machinery. ...
  • Environmental Damage.
Jun 10, 2020

Can a burnt out fan motor be repaired? ›

It certainly can be repaired - bearings can be replaced, rotors replaced, windings re-wound.

What is the most common cause of motor failure? ›

Bearings are the culprit in more than half of motor failure cases. Improper lubrication, inappropriate mechanical loads, heat, contamination and shaft currents are all the usual suspects when it comes to bearing problems. Get the bearing failure checklist.

What happens when a fan motor overheats? ›

Upon overheating, the motor will stop running, halting the HVAC system and potentially damaging other vital components.

Will a bad capacitor cause a blower motor to run slow? ›

The capacitor needs to be in good condition for the blower motor to function properly. If the capacitor is bad, the blower motor may run slowly or inconsistently, or overheat easily. If you notice that your blower motor works strangely or short cycles, make sure to contact professionals to inspect your capacitor.

What controls the blower speed? ›

The blower motor resistor is responsible for controlling the blower motor speed. In the past, this was done by varying the voltage supplied to the blower motor. In newer applications, the blower motor resistor is actually a solid state module that sends a varied signal to the blower motor.

How do I control my blower fan speed? ›

Adjusting the Blower Speed

To increase blower speed, slightly loosen the setscrew that holds the pulley to the driveshaft. Move or turn the pulley clockwise on the shaft one turn, then tighten setscrew. If more speed is desired, turn the pulley clockwise two turns.

Why does my blower motor keep failing? ›

The most common reason why your blower motor won't work on any speed is that you have a bad or blown a fuse. A fuse is a small wire inside of a connector that is used to protect the motor itself from a surge of electricity.

How long should a blower motor last? ›

How Long Does a Furnace Blower Motor Last? Blower motors are designed to last just as long as your furnace itself, anywhere from 10 to 20 years. Just as with any HVAC system, the better maintained and serviced your equipment is by experienced HVAC technicians the longer it will last and the fewer repairs you'll face.

How do you know if your blower motor is blown? ›

Key Signs of a Bad Blower Motor
  • Strange Rattling, Clanking, or Screeching. ...
  • Weak or No Airflow From The Vents. ...
  • A Sudden Spike in Your Energy Bills. ...
  • An Overheating HVAC System. ...
  • Replace or Maintain a Part in the Blower Motor. ...
  • Replacing the Blower Motor. ...
  • Keep Up With HVAC Maintenance.

What happens when blower motor goes bad? ›

If it happens, you will hear unusual noises like slapping or sudden pop coming from behind the vent. Problems with the airflow have signs such as ongoing whirring, getting louder when you increase the fan speed. Thus, at the sign of the first unusual noise, get your car checked.

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