Informational Guide

How To Replace Condenser Fan Motor in HVAC

Need to replace your air conditioner fan motor? We look at what is involved so you can do it yourself.

by Josh M

Your HVAC system’s condenser fan motor is hugely important. As the refrigeration unit works, it builds up heat which must dissipate. The condenser fan motor sends that heat out into the ambient air outside. Without this heat transfer, your compressor can overheat, which at best means your AC won’t cool, and at worst, could require extensive (and expensive) repairs.

When it comes to replacing fan motor in the HVAC condenser, when it’s time for it, it simply must be done to avoid damage to your system and allow your HVAC unit to function correctly.

Commercial Split Type Air Conditioner on Wall

Any number of issues can cause a condenser fan motor failure. Complicating is that just because the fan motor stops running, that doesn’t automatically mean it has failed, as there might be other causes for the stoppage. Still, many things can go wrong with the condenser fan motor.

Capacitor Problem

The capacitor serves as a kind of power storage service. When your fan motor needs to kick on and start spinning, energy stored in the capacitor kicks in to apply initial momentum to the fan. Capacitors also act as a kind of smoothing agent, preventing any voltage spikes from reaching the motor. If your capacitor goes out, your condenser fan motor won’t be able to start spinning when it’s needed.

Contactor Problem

The contactor in your HVAC unit is the switch that allows power to the condenser fan motor to turn off and on. Think of it as a light switch— if you have a perfectly functioning lamp and lightbulb, but the switch isn’t hooked up, you won’t get any light. When your contactor goes out, your fan motor sits useless because it can’t receive any power.

Burnt Out Motor

When voltage runs too high, the windings in your motor (those coils and coils of wire) can burn out. This is the result of a short circuit in them. Since the windings create an electromagnetic field that turns the motor, a short circuit in the windings means no electromagnetic exists, which means no turning of the motor.

Loose Or Broken Belt

Having a belt in your HVAC system is a sign of an older system. Belts help in the transfer of energy and making things turn. A loose belt might produce a squeak or squeal. Once it gets loose enough, it may stop turning the motor. A broken belt won’t turn anything, either.

Unit Not Receiving Power

This could present a chance for a simple solution, as it could be that your circuit breaker has tripped, and a simple reset will get the motor running again.

Blocked Air Filter

If you’ve ever tried to breathe through a cloth, you know it can require a bit more effort than without anything over your mouth. Your HVAC unit faces the same issue when filters get blocked. The filters exist to prevent particulates and debris from entering your system, but if too much of those things build up, the blockage will hinder the airflow.

Bad Fan Itself

If your fan isn’t working, and you’ve exhausted the above reasons as the culprit, the fan might have bad bearings or some other physical issue or damage. In that case, replacement is the best option.

Condenser Unit of Aircon AC

When To Replace The Condenser Fan Motors (Common Signs And Symptoms)

If you’re lucky (especially if you live in a place where having your AC go out would be a significant issue), before your condenser fan motor stops working altogether, it will give you a hint or two that it’s having some problems.

  • Fan Doesn’t Start or Stop
    These might be hard to notice if you’re not paying close attention to your AC and its on-and-off cycles, but if you notice that the fan has run for an inordinately long time or— the opposite— hasn’t kicked on in a while, your motor may be in trouble.
  • Slow or Still Rotating Blades
    Most of us have heard the unit kick on and seen the corresponding movement of the fan blades. If you only experience one part of that, there’s a problem. When the motor starts but the blades don’t, or if they seem to be turning slower than usual, there’s an issue that needs addressing, and soon.
  • Rattling, Humming, and Buzzing Noises
    A general rule in life with mechanical things is that new noises usually indicate some problem rearing its head. Misaligned or damaged fan blades could be the cause; there might be debris inside the unit, or it could be something worse. So, people with avoidance issues, beware: hear a new noise? Please don’t ignore it. It’s your unit trying to tell you it needs some attention.
  • Runs Intermittently
    If you discover your HVAC unit starting and stopping with more frequency than expected, there may be an issue with overheating, or your connector or capacitor may be beginning to fail.
  • No Cold Airflow
    Your air conditioner exists to make the air cooler. If it’s hot outside and the air coming from the vents isn’t cool, something is wrong. If a motor requires replacement, you’ll want to know about it sooner rather than later, and you’ll want it repaired quickly to avoid damage to the rest of the system.

How To Replace The Condenser Fan Motor In HVAC
(A Detailed Guide)

Once you’ve identified the need to replace the air conditioner fan motor, you may be able to do it yourself. If you have no mechanical skills, maybe not, but it isn’t all that difficult.

The very first thing you must do is shut down the power to the unit. Do this at the breaker box. Do not forget this step, and do not skip this step to save time.

Next, use your camera phone to take a picture of the wiring. You’ll want to remember what color wires go where. Alternatively, you can write it down or draw a diagram.

Remove the bolts holding the motor in place, then remove the screws securing the fan blade. Now you can pull the condenser fan motor out, and you’re halfway done.

With the replacement motor, work these same steps in reverse, taking care to reattach all screws and wires in their original positions.

Consider replacing the unit’s run capacitor at this time, too. It’s easily removed with a screwdriver. Since you’ve put in a new motor, it’s prudent (and relatively inexpensive) to put in a new capacitor, too.

Air Conditioner Compressor Outside a Room

Important Things To Take Note Before When Looking For A Replacement

Most units will take a universal condenser fan motor, but you’ll want to know some things about the unit you’re replacing before you buy its replacement.

  • Operating Voltage and Horsepower Rating
    These are not universal, so knowing the requirements of your old motor is necessary to get the right replacement. Also, note that different parts of your HVAC system may have different horsepower ratings.
  • Direction of Rotation
    You’ve got a 50/50 chance of guessing this correctly, but why? The motor turns in the direction of the lower edge of the fan blades.
  • Motor Diameter and Shaft Size
    Although some condenser fan motors are labeled “universal,” different HVAC manufacturers use different sizes in some of their parts. Measure the shaft and the motor’s diameter in inches.
  • RPM Speed
    Again, different makes spin at different rates. Know the RPMs your unit has been working with, and match that speed with the new unit.
  • Mounting System
    Most everyone has had the experience of buying a car part or some other mechanical gewgaw that looks exactly like what it’s replacing, but the mounting system is different, or the holes are just a little bit in the wrong spot. Take note of how your old motor mounts.

People Also Ask (FAQ)

How Long Do AC Fan Motors Generally Last?

You should expect to get about 12 years of use out of an AC fan motor. Maybe you’ll get lucky and get 15 years out of yours, but if you know your fan motor is older than that, good preventative maintenance might mean replacing the unit now before it conks out on you.

Should Condenser Fans Run All the Time?

If this question is, “Should it run 24/7?” the answer is no. If it’s running all day and all night, there’s a problem somewhere. But if this question is, “Should it run all the time my compressor is running?” the answer is yes. If your compressor runs and the condenser fan is off, there’s a malfunction that needs investigation and solving.

How much does it cost to replace an HVAC fan motor?

Doing it yourself, you’ll get out of it for the cost of the motor itself—likely up to $200. A professional replacement job will include labor costs and may set you back as much as $400.

Conclusion

When it’s time to replace HVAC fan motor, you have the option of doing it yourself. This is a plus because replacing air conditioner fan motors is the kind of thing that needs to be done as soon as possible, lest your family swelter in the heat.

Recognize and act upon any signs of impending disaster with your HVAC condenser fan motor, as it’s common for the system to give you some hints that things are going wrong before it completely breaks down.

Josh M

My name is Josh and I am obsessed with the HVAC industry. I created this website to help HVAC techs of all levels get the best out of their heating & cooling systems. I have spent thousands of hours studying air conditioners, heaters and home air products so you can learn & buy with confidence. Learn more about the team here.

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