We all know that amazing feeling of coming in from a hot summer day into your beautiful AC. But, one day, you may go in and find that your home isn’t as cool as you expect.
Some people also know the sinking feeling of a broken AC unit. However, knowing that you’re in for a costly repair is not something anyone should have to experience.
With summers getting hotter and June 2021 smashing records, you need working AC.
Before you go out and get some drastic work done, you may need to ask yourself the question, “Do I have a bad AC capacitor?”. If you do, there’s good news – you can replace it yourself.
Check out the symptoms and replacement guide to see if this is you.
Safety Warnings
Many AC units have capacitors that carry quite a high charge, so you should absolutely be careful when replacing or inspecting them. However, if you take reasonable precautions, you should have no problems.
- Never touch terminals on the end of a capacitor
- Don’t use something metal to discharge the load on the Capacitor
When working with high voltage equipment like an AC unit, always make sure it’s off. If your AC unit is a plug-in type, make sure the plug is completely out. If your AC is connected to a breaker, make sure that the breaker is disconnected or down.
Symptoms
AC units that have bad capacitors can throw up several interesting symptoms. Though it’s not always a one hundred percent guarantee of a bad AC capacitor, the chances are good that you have a problem if you see any of these.
You may notice:
- Burning or electrical discharge smell
- Higher than normal bills
- The unit may randomly shut off
- Problems with turning on or off
- No cooling
- Clicking or humming noises
If any of that sounds familiar, there’s a good chance that there’s something wrong with your AC capacitor, and you should consider replacing it.
If none of these symptoms fit, take a look at our troubleshooting guide to find the problem.
No Cooling
Once your AC stops blowing cold air, it’s a sure sign that something is wrong. It’s possible that this isn’t a long-term problem. You can test by turning your unit on and off again to see if the problem goes away.
High Energy Bills
When an AC capacitor is bad, the AC unit has to work harder to make things cooler. So when you suddenly notice your energy bill going up, you may have a bad capacitor. To understand why a bad capacitor means a higher energy bill, see our section below on what a capacitor does.
Random Shutoffs
You might find that your AC unit switches itself off without you doing anything from time to time.
Problem With Turning on or Off
This problem is almost always because of a bad capacitor. When the system is trying to do something that needs more energy, a bad capacitor can cause issues.
This symptom might also show up as the unit taking a long time to start working after you turn it on. The Capacitor gives the initial jolt of energy, and when it fails, the AC unit struggles to start.
Burning or Electrical Discharge Smell
This one is a little more complicated as there may be many reasons (none of them good) why your AC unit might smell of burning. In your AC unit, the Capacitor drives a motor. When the capacitor is bad, the motor tends to overheat, and this can cause the smell.
Clicking or Humming Noises
This one is related to the motor again. When the motor tries to start but cannot, it may make a clicking or humming noise. This is a good sign that the Capacitor is broken.
Now that you have a good idea of the symptoms you might see, let’s learn a bit about how capacitors operate. That way, you can understand how to replace them safely and efficiently.
What does a capacitor actually do?
If you think about a capacitor as a large store for energy, you’re on the right track. The simplest Capacitor has only a few components. These are two conductors that allow electricity to flow and gaps that block the flow of electricity. When electricity is run through the Capacitor, electrons are stored in the two conductors. One conductor stores negatively charged electrons, and one stores positively charged electrons.
Any large appliance like an AC unit requires a lot of electricity to run. And, when they’re starting up, they need a large amount of energy. You wouldn’t want to pay top rates for your electricity all the time – this is where capacitors come in.
Capacitors use the stored energy to give a big jolt of power to your AC when it starts up. You may have heard the noise when this process starts.
Once the unit has started up, the Capacitor isn’t needed as much, and it can go back to storing up energy for the next big push.
What Is Capacitor Rating
A Capacitor has many different ratings, but for our purposes, we only care about two:
- Working Voltage
- Capacitance Value
Working Voltage
This is really just an indicator of how much voltage can pass through the Capacitor. One of the reasons a capacitor may break down faster than expected is if you have inconsistent power in your home.
Capacitance Value
Measured in microfarads, this shows how much energy a capacitor can store. There are some other complications around this, but you should be fine if you can quote the Microfarads.
How to Tell if an AC Capacitor Is Bad
The most common symptom from the list above is that your AC unit will stop blowing cold air. When this happens, the Capacitor is not functioning and cannot deliver enough stored energy to run the system.
Besides all the symptoms in our list, there may be visual signs that there’s something wrong with your Capacitor. If you can see the Capacitor on your AC unit, it’s easy enough to inspect for damage or other functional problems.
Visual Indications of a Bad AC Capacitor
Take a close look at the Capacitor in your unit. Does it look smooth and unblemished? If there is any noticeable bowing or bulging, the Capacitor needs to be replaced. In the same way, if there is oil coming from the top of the Capacitor, it’s reached the end of its useful life and needs to be replaced.
How to Replace an Air Conditioner Capacitor
AC capacitor replacement isn’t difficult and can be DIY in most models. Each model differs, so there might be a slightly different process depending on your make.
The basic steps are:
- Turn off and unplug your AC unit
- Open or remove the panel that gives you access
- This is usually found on the side of the unit and is marked
- Check what the broken Capacitor’s rating is
- Take off the old Capacitor
- Install the new Capacitor
- Turn on the AC unit and give it a test
Although this is a relatively simple installation, we suggest reading to the end of the instructions. You will have a complete understanding of what you’ll be doing this way.
Gather Your Tools
Do you need a screwdriver to remove your access panel? When you get to the capacitor removal, you may need both a 1/4 inch screwdriver and a 5/16th driver.
Turn off and Unplug Your AC Unit
Make sure that you have turned off your AC unit properly. If it is a plug-in type, ensure that the plug is in the off position. Physically unplug the AC unit if possible. Otherwise, please turn off the breaker for your AC unit so that it is safe to work on.
Open or Remove the Access Panel
This should look like a small, hinged door. It usually appears on the side or underside of an AC unit. Some panels require a screwdriver to open, while others have a latch.
Be careful when opening the panel that you have a safe place to store it if it comes out entirely.
Find The Capacitor
The Capacitor in your AC unit will look like a metal cylinder. It will have either two or three terminals on the top and should have wires connected to it.
Inspect the Capacitor
Do a quick visual inspection of the Capacitor. Can you see any bulging? Is there any oil leaking down the sides? If anything looks deformed or strange about the Capacitor, it’s probably bad.
Check Capacitor Rating
Take a close look at the Capacitor. Here’s an example that shows the label. It should have a label on the side that will tell you everything you need to know about it. Remember, from what we saw above; we are interested in two ratings:
- Working Voltage
- Capacitance
Working Voltage Rating
This will usually be printed near the top of the label and have the letters VAC after it. You might see text similar to “370/400VAC”.
Capacitance Rating
This will usually be printed underneath the Voltage rating and will have the letters uF or µF after it. You might see text similar to “50uF” or “40+5MFD”.
Take off the Old Capacitor
First, take a picture of the old Capacitor in place. This will help you later when you put in the new one. There should be three connectors – HERM, fan, and C. It’s essential that when you put your new Capacitor back in, you connect it in the same way.
Once you have taken a photo of the connectors, carefully disconnect them. Any disconnected wires should be put aside where they won’t get in the way.
The Capacitor should be simple to remove. They usually only need one or two screws to be removed, and some are snap types. If screws are holding the Capacitor in, make sure you keep them somewhere safe.
Install the New Capacitor
One by one, attach the wires as they were on the old Capacitor. Make sure that the correct wires are going to HERM, fan, and C connectors. Double-check that you have them right before proceeding.
Once you are sure that you have the suitable connectors in the right place, it’s time to mount the Capacitor again. Take the screws you removed previously and install the Capacitor using solid pressure. Be careful not to strip the screws when installing.
If the Capacitor does not use screws to install, it should simply snap into place again.
Close and Secure the Access Panel
Don’t forget to put back any screws that might have been holding the door closed. An open access panel could be dangerous and should be properly closed.
Turn on the AC Unit and Test
It’s time to bring everything back up again. If you disconnected or pushed down a breaker, reconnect it. If your AC unit is a plug-in type, re-insert the plug and turn it on at the socket.
Once everything is back in place, you can turn your AC unit on as usual and see if it operates.
Testing
Testing is as simple as turning on the AC unit and setting it to cool. You should see a marked difference. Everything should now be working properly, and your room should begin to cool down.
AC Capacitor Replacement Made Easy
So, now that you’ve gained this new ability to fix your own AC unit, what else is left? Well, for a start, you need a good, reliable place to replace your bad AC capacitor.
Fortunately, that’s really easy. You can contact our parts people or call us direct to talk to a friendly technician. We will help you determine which Capacitor you need based on your make and model or the capacitor rating.