The Troubled Ten! Common A/C Problems by HELP!! Air Conditioning

All mechanical systems will require some type of repair from time to time, but most of these problems are preventable with proper maintenance.  In no particular order, we have created a short “top 10” list of the most common air conditioning problems we come across each spring and what you can do to help prevent them.  We call these “The Troubled 10."

1 | Tripped Breaker

One of the most common causes of “no-cool” calls is a tripped breaker or a blown fuse.  Breakers and fuses always fail for a reason.  You can try to reset the breaker or replace the fuse, but if you aren’t trained to do it safely, you should consider letting a qualified service technician look at everything for you.  If the breaker trips or the fuse blows more than once, there is some underlying problem causing it to do so. 

Hopefully, it will be something simple like a loose connection, bad breaker or a bad capacitor.  However, if the cause is not addressed, some of these simple causes can lead to major and expensive repairs.  Electrical systems are nothing to play around with and in some circumstances can cause serious injury or death, which is why a trained professional should always look at these items for you. 

Even though a tripped breaker or blown fuse doesn’t sound like much, it can lead to minor problems that could become major issues if not corrected quickly.  Many premature air conditioner deaths could be prevented by addressing issues like this the first time a problem arises. 

Common Problem 1: Bad Start Kits - This helps start your compressor easier.

2 | Dirty Filter
If you use a one-inch disposable filter, it should be replaced every month.  Filters are one of those “out of sight and out mind” type items, so it’s easy to forget to change them.  Still every year we go on service calls where the filter is the only cause of units not cooling. 

Dirty filters restrict airflow which can cause an air conditioner to “freeze up”.  Left unattended, it could cause even more problems like water leaks and internal damage to your compressor.  Changing your filter regularly can be a very inexpensive way to lengthen the life of your air conditioning and heating system. 

There are many choices when it comes to choosing a filter for the health of your air conditioning system as well as your family. However, not all filters are created equal and there are some you should never use. 

In most cases, a standard pleated filter is the only one you should use.  Why?  Most return air grills are undersized so when you use a filter that restricts airflow you are basically sending your air conditioner to an early grave. The filters that claim to be allergy filters are among the worst at restricting air flow.  

Talk to your technician and ask him what your best option is.  I personally like the five-inch filters that fit directly into your existing return grill and can last up to 6 months. 

Common Problem 2: Dirty Filters - Restrict air flow.

3 | Refrigerant Leaks

An air conditioning system is sealed and shouldn’t need to have Freon added to it.  The most common area Freon leaks occur is in the evaporator coil.  

Manufacturers make the copper or aluminum as thin as possible to get the most cooling they can from the coils.  Freon travels very fast through the tubing which eventually causes a leak.  All coils will leak at some point in time, some will leak sooner than others and there is no rhyme or reason for it. 

If you have a system using Freon 22 and a leak is discovered, you need to consider replacing the system with one that uses the current refrigerant 410a.  Freon 22 is no longer being manufactured and the cost will continue to rise making it too expensive to keep adding Freon each year like people used to do.

Running your system while it’s low on Freon can also cause lots of problems with the system.  For instance, not having enough Freon can cause a decline in efficiency, which increases the amount of electricity needed to run it.  It can also cause your evaporator coil to freeze and damage the compressor.  Find the leak and repair it or replace the part that’s leaking.

4 | Weak Capacitors

Capacitors are put into different areas of your air conditioning and heating system.  They allow the motors (condenser fan motor, compressor, and indoor blower motor) to run more efficiently thus making them last longer. 

A weak or bad capacitor can cause the motor to run hotter and less efficient, shortening the life of some of the most expensive components within your air conditioning and heating system.  This is one of the easiest fixes a technician can have yet can be the costliest for a homeowner. 

What do I mean? A capacitor doesn’t have to be completely out to cause other problems.  It can become weak with use and time and in its weakened state will cause whichever motor it’s connected to run hotter. When this happens, it’s wasting energy, causing you to pay higher bills than normal. 

This type of issue will also shorten the life of the motor it’s connected to.  This problem, in most cases, can be discovered during regular maintenance-- saving you the heartache of waiting in a hot house for a service technician to come see why your system broke down.

5 | Clogged Drain Line

Air conditioners remove moisture from the humid air in your home while lowering the temperature.  The moisture is typically drained out of your home through the plumbing system of your house.  However, algae can grow in these lines, causing them to eventually clog up.  This can lead to water damage on your floors or the ceiling sheetrock.  When a technician is called out, they should typically blow out the lines to help in reducing your chances of these drains clogging up. 

There are a couple of items I recommend to my customers to reduce the risk of getting clogged drain lines. I recommend installing a pan pad, which sits in the drain pan of your evaporator coil.  Additionally, a float switch can be installed in the primary drain line to help reduce the chance of water damage to your home.

These items can help reduce the buildup in the drain pans and the drain lines.  This does not guarantee you’ll never have a drain issue, but it does greatly reduce the chance of having one.  Customers who use these tools, along with performing regular maintenance, have fewer water leaks than any other customers. 

Here’s a picture of what the inside of your drain system could look like if it’s clogged.

Common Problem 5: Clogged Drain -  Precautions such using as a pan pad and drain cleaners prevent clogs.

6 | Contactor

A contactor, located in the condenser, is an electromechanical device located that turns the air conditioner on and off.  Sometimes the contact points become corroded and pitted, which can cause a contactor to stick closed or cause higher-than-normal amperage, resulting in higher utility bills. 

Contactors send electricity to all the moving parts inside your condenser or electric heater through their contact points.  Because these points open and close many times throughout the cooling season, they can become pitted.  This causes the unit to run higher amperage, wasting electricity.  After the summer beating this particular part takes, a few things could go wrong. 

Of all the possibilities, you might hope that the unit just doesn’t turn the unit on because the contact points aren’t closing.  Alternatively, the points could actually weld themselves closed, causing the unit to never turn off.  If the unit never shuts off this could cause the indoor evaporator to become covered in ice and cause damage to the compressor. Or, as the ice melts not all of the water will go through the drain line which means you could have water leaking through the ceiling. 

Cleaning the contact points or replacing the contactor during normal maintenance can greatly reduce the risk of the air conditioning quitting on a hot afternoon.  Although this part doesn’t seem all that impressive, it is the part that tells the condenser (outdoor compressor) to turn on and cool your home.  

The contactor, like a capacitor, can appear to be fine but could actually be costing you more money to operate. 

This is a problem that is easily avoided with regular maintenance.  Can you tell me which contactor is good and which is bad?

Common Problem 6: Bad Contactors prevent your air conditioning unit from properly shutting off.

7 | Dirty Evaporator Coil

Dirty coils greatly reduce the system’s ability to transfer heat, which means uneven and unsatisfactory performance.  When an evaporator coil starts getting dirty it will start to create other problems. 

Dirty coils reduce airflow which will make the coils colder. Sounds like that would be a good thing doesn’t it?  It’s not.  The colder the air gets, the more likely your duct will have sweating problems, which will cause mold and mildew to grow.  This also puts a strain on the compressor, causing it to run higher amperage wasting more energy.

Coils may need to be brushed down and cleaned periodically.  Ensuring the evaporator stays clean is a very important function of maintaining your air conditioning system’s cooling ability.   This is also where changing your filter regularly (see above) can become vital in maintaining the overall health of your system.

Common Problem 7: Dirty Evaporator Coils reduce air flow and must be cleaned regularly.

8 | Dirty Condenser Coil

A dirty or restricted coil will reduce your air conditioner’s efficiency and reduce the cooling capacity while increasing your energy consumption.  When you don’t have proper airflow over these coils it causes the outdoor unit to run hotter, drawing higher amperage and wasting more energy than anyone should. 

The two worst enemies of outdoor units are grass and animals. Grass is the biggest issue we come across because few people know to turn the unit off when cutting the grass around it. 

Another big problem is pets, and it’s not just because of their hair. Dogs are known to urinate on condensers, which rots away the aluminum fins on the condenser coils.

Pet urine can rot away aluminum fins on the condenser coils.

You might say, “Well, I’ll build something around and over the unit to protect it.”  Before you go out and buy supplies, you should consider that the outdoor unit should have at least 2 feet of clearance all the way around, plus your service man needs room to work on it. 

Dirty condensers make your condenser fan motor work harder as well it reduces the unit ability to cool your home properly.  However, taking steps such as turning your unit off while cutting the grass or regularly cleaning the condenser coil (at least once per year) are positive steps towards ensuring your condenser coils stay clean.

Common Problem 8: Dirty Condensers

9 | Duct Leaks

Your duct system delivers air to all the rooms in your house.  Air leaks will reduce the amount of air being delivered to these rooms. 

Some duct leaks can cause higher dust problems in the house as well.  A sealed duct system, accompanied by a high-efficiency filter system, can help reduce the amount of dust in your home. 

The most common duct leaks we find are in the return ducts or “chase ways” behind the return filter grill.  Building codes have changed and now require all chase ways to be sheetrocked, taped, and floated. But this doesn’t mean they’re sealed properly.  If yours does not have sheetrock, it will pull hot and unfiltered attic air into your air conditioning system because it’s not sealed where the wood meets in the corners. 

We also frequently find air leaks in the attic where the return plenum connects to the chase way.  The easiest way to seal all these is and using cans of expanding foam.  These air leaks can cause dust problems in your home. 

One of the other big problems associated with this is supply air leaks.  For years everyone just used plastic straps to connect the duct ends to the plenums and register boxes, but we learned that you can leak a lot of air if those aren’t sealed properly. 

In some cases, you can use a good quality duct tape while other times you must use mastic.  The benefit of using mastic is that it can be painted on and will dry hard, sealing the duct almost permanently.

A quick, but not entirely scientific test to see if you have return air leaks is to stand by front or back door while the system is running.  Once the door is open feel to see if air is rushing out of the house; if it is then you are pressuring the house and have return leaks.  If air rushes into the house then you have supply air leaks and will be cooling your attic more than needed.

Now, this isn’t the true way to test your duct system, but it’s a low-tech way you can check it yourself.  The true way to know is to have your duct system tested with specialized equipment.  Duct leakage should be less than 6% of system airflow.

10 | Wire Connections

Loose wire connections (both high and low voltage) can cause higher than normal amperage draw.  This high amperage draw can make wires overheat, melt, or burn completely off.

All electrical connections should be checked for loose or frayed connections as they can cause a wide array of problems and shorten the life of your air conditioning system.  Wires that should be checked regularly include compressor connections, indoor and outdoor fan motors, contactors, capacitors and the disconnect box next to the condenser. 

Even though service technicians deal with the electrical surrounding your air conditioning and heating system, you should have a qualified electrician check the main panel feeding electricity to the entire house.  Not only are they very important to the performance of your air conditioning and heating system, we’ve seen loose connections there cause house fires.

It's Best To Get Some Help!!

Many of these problems can be avoided by simply having a trained technician perform a yearly tune-up on your complete air conditioning and heating system but that doesn’t guarantee you’ll never have a problem.

There are 3000 hours of cooling and heating hours here in New Orleans and, as you might have guessed, our cooling hours take up most of that time-- approximately 2400 hours of it.  Treat your cooling system well and have it cleaned yearly.  You wouldn’t drive your car and never change the oil, would you?

Written By,

Korey P. Knobloch
HELP!! Air Conditioning

Korey has been in the air conditioning industry since he was 16 years old and helping with the family business for over 34 years.  Like most others in the industry, he learned the ropes as a helper before working as an installation tech, and finally service technician. Now, as a business owner, he’s happy to have more time to enjoy his passion for educating customers on the many misunderstanding of the industry he grew up in.