Repairing an Air conditioner is not an easy task especially if you don’t know anything about it. If there is a minor issue with the AC then you can try to tweak it. But if the problem is bigger and you don’t anything it’s better to call a professional. 

A little about me I have been repairing ac for 6 years now. It’s basically my main source of income (my bread and butter). Over the year I receive too many calls about ac repair and I know what are the most common problems that people face with the air conditioner.

So In this article, I have listed all of the most common problems that can occur in your central ac and how you can troubleshoot and repair it.  

AC Repair #1: Check Your Capacitor

The number 1 problem faced by an ac owner is the bad capacitor inside the condenser unit. A lot of times when the capacitor goes bad it'll bulge out on the top and sometimes the whole top will actually pop off.

And because of this, you'll have that dielectric grease all over your electrical section. But there are other times when the capacitor actually looks good but it's still dead and the only way to really check that is to use a multimeter.

You have to make sure that you don’t blindly replace the capacitor because I have seen many people do it (it’s the most common fix).

A capacitor has a life and they do die with time and it’s normal. But what speeds up their death is a very dirty condenser coil and a dirty inside filter.

You need to check and clean them at regular intervals. The heavy thunderstorm also seems to take out a lot of capacitors. In that case, you need to replace them with new ones.

Click Here To Check Our Detailed Tutorial on How to replace your Capacitor At Home

AC Repair #2:Check Your AC Refrigerant Levels

The second most reported problem is low refrigerant. Here's something you should understand about an AC. It is a permanently sealed system meaning whatever freon is in there stays in there for life.

It's not like gasoline where you have to occasionally pour some in so if some freon is missing that guarantees that you have a leak somewhere.

It can either be in the outside unit of AC or in the coil that's on top of your furnace or on the line set in-between usually at one of the braze joints.

So you could call a technician and get that refilled but do keep in mind that with time that inevitably will leak back out. It usually only lasts one season because it is a pressurized system so even during the winter it's slowly leaking out.

If you hire somebody to fix that leak for you they say that 80% of the time the leak is found in the coil which is on top of the furnace.

That leak typically cannot be repaired and you have to replace the whole coil because the solder joints are so close to each other when you start melting one of them to fix it, the one right next to it melts as well.

And a coil alone is anywhere from $600-$1000 and then you add the trip fees the labor fees and part fees it gets pretty expensive to fix a leak so most people would rather spend a couple of hundred bucks every year refilling it or they just replace the whole thing altogether

AC Repair #3: Clean Your Condensate Drain

The third most commonly reported problem by ac owners is the plug condensate drain.

So you come home and there’s water leaking everywhere in this type of situation the ac is working fine and you won’t even notice anything wrong so what causes the leak.

So the cause of this problem is the hose that comes from the drain fitting from the AC evaporator coil (On the top of the furnace). So in this case all you have to do is clean the drain fitting system.      

AC Repair #4: Repair Your Bad Control Board

The fourth most common problem is a bad control board. There are many problems that can occur due to a bad control board like the control board will not sending power to the outside unit when the thermostat is calling for cooling.

Or sometimes it'll be doing wacky stuff like turning on the furnace at the same time as the AC is running. Sometimes the control board could have a bad fan relay on it so it's not sending power to the blower motor and due to this the AC turns on but the blower motor and the furnace do not.

And when that happens then there's no airflow for your coil that's on top of the furnace. And it’ll freeze over in like a minute and the longer you run it the thicker that ice layer will be on that coil. In this type of situation, you’ll have to replace the control board.  

AC Repair #5: Replace Burnt-out Condenser Fan Motor

This type of situation occurs when you turn your AC On and the compressor will start running but the fan will not. And eventually, you'll feel a lot of hot air coming out because that compressor is overheating and it'll probably trip a breaker.

What most people will do is they’ll take a screwdriver and try to spin that fan blade and you will notice that it's really stuck and it does not spin freely.

You can try to take the motor out and oil it but from what I've seen in the past oiling it does not really do much good in like a week or two it will cease back up again. So the fix for that is replacing the whole motor and generally when we replace the motor we always replace the capacitor as well. 

AC Repair #6: Replace/Repair Bad Blower Motor

This problem occurs inside the furnace with the motor blower (when it’s burnt out). A lot of times it'll smell like a burnt electrical smell and if you take out the bottom during your furnace reach and try to spin that blower wheel usually it'll be all seized up.

Or you may have noticed sometimes there’s a humming noise coming from the blower motor. And if you give it a spin it'll actually turn on what that means is that the capacitor for that blower motor is dead.

You can replace that capacitor and get it to work but most of the time a few weeks later the blower motor will also be burned. So generally if a capacitor is fully dead for a blower motor you just have to replace the motor as well because it doesn't have much life left in it.  

AC Repair #7: Check Your Compressor Unit

The next problem is a compressor that is shorted to the ground. In this type of problem the circuit breaker of the AC just keeps tripping.

So what most people/technicians will do is reset the breaker and turn the AC on and what it does is it’ll immediately cause a trip in the breaker again.

In this type of situation first, you have to check for the burnt wiring and then the windings of the compressor pins. If the wiring is burnt then it’s an easy fix but if the windings are shorted of the compressor then it’ll be an expensive repair. Most of the time the compressor is shot so you have to replace the whole unit.         

AC Repair #8: Clean/Replace Your Dirty Furnace Filter

A filter is a very easy thing to forget about and some people forget about them for a long time like a year or two and when you pull that thing out it's like black.

And when your airflow is restricted that much it's almost like the blower motor is not even running so the coil on top of the furnace will freeze over so don't forget to change your furnace filters.

So most people also ask that what filter should we use I would recommend a medium grade pleated filter  

AC Repair #9: Check Your Tripped AC Breaker

Most of these trip breakers tend to be just a nuisance trip so you'll reset the breaker and it'll work fine for the rest of the season. But if you reset that breaker and it trips again then you do have a problem and you should investigate.

Because there's probably a short somewhere most likely a wire is broken off or melted and it's touching some metal and it's causing that AC to trip.

AC Repair #10: Clean Your Dirty Condenser

If you’re checking your AC after a long time then you’ll look at the coil and there'll be like half an inch to an inch of cottonwood dust leaves and whatever else just plastering the coil.

This dirty condenser can cause many problems like tripping a breaker or simply not cooling the house. You have to clean it at regular intervals. The best way to clean is by spraying water either from inside or outside. Both the processes will get the job done.

AC Repair #11: Replace/Repair Bad contactor

A bad contactor can be something obvious where half of it is melted off or you look at the coil and it's all warped.

Sometimes the contactor will have no visible damage but if you mount the coil the resistance will be way high that way you know the contactor is bad too. The best solution for the bad contactor is a new replacement. 

AC Repair #12: Reapir Evaporator Drain Pan Leaking

A coil of drain pan that is leaking what that will look like is your AC is running great it's draining down the hose but at the same time, you still have a puddle underneath your furnace.

That usually indicates that you have a leak somewhere in the drain pan that sits below your furnace it's about an inch and a half tall and if it’s metal it can rust and get a hole in it eventually.

Most of those drain pans are welded to the underneath of that coil so to replace that drain pan do have to replace the whole coil.

AC Repair #13: Check For Mouse Damage

Your Ac is not working so you take off the electrical panel you look inside and there's a big mouse nest. You have to clear all that out and then check all the wires looking for places where the mice chewed them up.

Many times you will find the mouse electrocuted on the contactor or sometimes it's wrapped around the capacitor.

AC Repair #14: Check For Broken Wires

Wires do lose their quality over time and they break easily. The connectors that connect to the terminals of the whole unit are vibrating so with time sometimes those connectors do get pretty nimble and they break off easily.

And that's actually a very easy fix if you see any broken wires you just snip that piece off-strip it put a new connector on put it right back on and you should be good to go.

AC Repair #15: Check Your Locked Rotor Amps:

The compressor with locked rotor amps which means the fan will come on but the compressor will just hum every 20 seconds.

So your capacitors already replaced it's brand new yet it's still not turning on that probably means that your compressor is drawing too much amperage at startup and it's locking itself up a lot of times.

We're able to free it up and get it to run by putting in a hard start kit the SPP six and that usually cuts the startup amperage in half and a lot of times your compressor will start back up.

Although there are times when I put that thing in and even with the hard start kit it still does not start in that case your compressor is locked up and you just simply need a new one or you have to just replace the whole unit with the other one.

AC Repair #16: Check Your Inefficient compressor

Sometimes you will find that the compressor is not pumping out the refrigerant like it should which means the valves inside they're getting weak and unfortunately there is nothing you can do that when your compressor becomes inefficient. The only fix for that is replacing the compressor.

AC Repair #17: Check Out Freon Level

Sometimes there's no freon in the AC unit and it's in a negative pressure that usually indicates that you have a very big leak and you will have no cool air coming out of your vents at all. 

Few Minor Problems You Must Look For

Furnace Switch OFF

Sometimes furnace switch was accidentally turned off by some technician. When the furnace switch gets turned off nothing works so all I got to do is flip that furnace switch back on and everything starts working.

Blown AC disconnect fuses

This problem occurs once in a while although it’s not a major problem. Sometimes your AC disconnect fuses will trip. You can just get the fuses replaced and everything will work fine.

Restricted Metering Device

The metering device is either a piston or a TXV that goes in front of your coil. If that's restricted you will need a technician to fix that for you.

Broken Fan Blade

Sometimes Fan blade gets cracked and when you try to run the AC the blades spin and the whole thing just flies out. It’s an easy fix you just need to get the blades replaced.

Bad Thermostat

A bad thermostat can be troublesome. So basically what the thermostat does is it tells your ac when to cool. It’s the main control center of the AC. You either need to tweak the thermostat or just replace it. Click here to see how to check and bypass the bad thermostat?