If you live in a hot environment, as do I, your central air conditioner isn’t just a luxury. Where I live in Southern California the summer temperatures can soar up around 115 degrees. One day several years back the mercury hit 117 degrees! You would have thought you were in Death Valley! During times like these central air is a survival necessity. It is also at times like these, when your AC is working its hardest, that it will choose to give up the ghost. However, there are some routine checks you can do to help prevent it from happening to you at the worst possible time.

Change the Filter Regularly

We learned this first lesson the hard way around eight years ago during a particularly hot summer. We had bought our home new. It was nothing spectacular, a 4-bedroom, 2 ½ bath two story tract home. But it was ours and we had scrimped, saved and spent every dime we had on it. As it was our first home, I had no experience in home maintenance. I had no idea I was supposed to change the filter on the AC unit regularly. Heck, I didn’t even know there was a filter to change! Yeah, I know, how stupid could I be? But unless someone tells you, how do you know?

It turns out that filter is there for good reason. If you don’t change it regularly you are asking for big trouble. The filter helps remove all kinds of nasty things from the air that is ultimately pushed through the evaporator or cooling coils of your air conditioner to be cooled. Things like dirt, dust, pet dander, fabric fibers, and pollen, whatever.

The evaporator coils of your air conditioner look a lot like a radiator. Lots of metal fins are attached to the coils to increase the surface area so the air flowing through the coils can be efficiently cooled. If the nasty stuff mentioned earlier isn’t removed by the filter before it hits the coils, then the coils will do the filtering. Over time, the coils will become clogged and the air flow will be reduced. As the air flow is reduced so is the cooling efficiency. If this goes on long enough, the coils will become impacted.

If the coil becomes sufficiently impacted, the coil may actually become so cold that the condensate forming on its surface freezes, completely blocking the coil. In my case, the blocked evaporator coil caused the compressor outside to be on almost constantly causing it to overheat and eventually fail. As the evaporator coil was so impacted it couldn’t be effectively cleaned, I had to have a new evaporator coil installed in addition to a new outdoor compressor unit. Add refrigerant and installation and my wallet was $3250 lighter!

So, take it from me, change your AC filter regularly. I taped a chart on my AC unit that reminds me to do so and lists when the filter was last changed. You need to be somewhat aware of just how dirty your local air is. My region of Southern California is quit dirty with a lot of particulate matter. Areas like this will require you to check and change your filter more frequently. Other areas may not require changes as frequently. I change mine every month now whether it seems to need it or not. It is cheap insurance.

Also, don’t try to save a couple of bucks on a cheap filter. It is not worth the risk. You will pay the difference anyway by having to replace the cheap filters more frequently. Cheap filters are more porous and allow more particular matter through to the condenser coils. Bite the bullet here and pay for the better quality filter. Buy a few extra to have on hand because this is a task that can easily put off if it requires a trip to the home improvement center.

Clean the Condenser Coil

You should clean condenser coil as often as needed. The condenser coil is the coil on the outside unit that houses the compressor. The fins on this coil can also become clogged with dust and debris from your yard. Simply pick out the larger debris like trash, leaves and pine needles.

To remove the dust and dirt build up, you can thoroughly spray the coil fins with a garden hose. This is usually sufficient to insure adequate air flow over the condenser coils. Be careful not to use a stream of water strong enough to bend the radiator fins. They are quick thin and bend easily.

Clean the Evaporator Coil

It is recommended that you inspect and clean the evaporator coil annually. The evaporator coil is usually located directly above the blower motor in the indoor unit. You may have to remove some duct work above the coil to complete this task.

The evaporator coil can be cleaned with commercially available AC coil cleaners. I use AC Fast coil cleaner. It is self-cleaning foam cleaner that does an excellent job of cleaning grime and debris from the coil fins. Be careful not to spray the cleaner on any wires or electrical components as it could damage them. The normal condensation on the evaporator coil is enough to flush the cleaner from the coil.

You can also clean the evaporator coil with a gentle spray from your garden hose or a spray bottle. You should spray the water through the evaporator fins in the direction opposite that of the normal air flow. Be careful not to spray water so quickly that the drain pan overflows as water may enter the rest of the AC unit.

Cleaning the condenser coil is a task anyone can do. Doing it on a regular basis will help extend the life of your coil and improve its efficiency. However, you may not be comfortable or have easy access to the evaporator coil. In these cases, you may want to leave the task to a trained AC technician.

Check the Contactor Annually

You should check the contactor on your AC unit annually. The contactor is located on the outside unit that houses the compressor. You will usually find it behind an access panel where the electrical wires enter the unit. Some contactors may actually be located inside the housing requiring the housing to be removed.

Basically, a contactor is an electrical device that takes a control signal from your thermostat and allows power to flow to your AC compressor outside thus turning it on. When the temperature in your home reaches the point you have set, the thermostat sends an electrical signal to the contactor on the outside compressor unit, turning it on. When the thermostat senses the temperature has fallen below the temperature you have set, the signal to the contactor is stopped and the AC turns off. It’s simple.

The contactor gets its name from the contacts found within it. When the contactor coil is energized by the signal from the thermostat, contacts with the unit close allowing AC power to flow to the compressor. When the contacts open and close arcing occurs. Over time, this arcing will cause the contacts to become pitted. If the pitting gets bad enough, the contacts can begin to chatter causing the compressor to cycle on and off constantly. This can damage the compressor to the point where it needs to be replaced. The typical contactor typically needs replacement every 4 to 6 years depending on how much your AC is used.

A typical contactor can be purchased for anywhere from $25 to $300 dollars depending on where and from whom you buy it. If you buy one from the AC tech at your home fixing your AC, expect the price to be in the upper part of that range. However, if you have the part number, you can probably locate the part yourself and save a bundle. When I replaced mine last time, the AC tech wanted $285. I was able to locate one online for less than $100. Either way, they are a lot less expensive to replace than a $2500 compressor unit.

Care should be taken if replacing the contactor yourself. Be sure the power to the AC units is turned off at the junction box and that the AC power disconnect has been pulled. If this is not a job you are comfortable doing, have a professional do it for you. It is better to be safe than sorry, or dead.

First look on the coil of the contactor and find its voltage. Most contactors will have a label with this information. If you are not sure of the voltage, check the installation manual for your system.  Almost every major brand home AC unit uses a 24 Volt 30 Amp 2 pole contactor.

Be careful when touching the terminals. Often the capacitors are still charged and can give you a nice jolt even after the power has been disconnected. Allow the system sit for a while after disconnecting the power to allow the capacitors to discharge fully before you begin to replace the contactor.

Install the new contactor in place of the old one and attach the electrical wires matching the old positions to the new contactor. Double check your work before turning the power back on. I took a close up picture with my digital camera prior to disconnecting the old contactor so that I could be certain which wire goes where when I wired in the new contactor.

Benefits of Regular Maintenance

Besides the obvious benefit of having an air conditioning system that provides comfort on hot summer days, performing regular maintenance will help keep small problems from becoming major ones. As mentioned earlier, my failure to regularly replace a $7 air filter ended up costing me $3250. Ignorance (or laziness) can be very expensive.

Additionally, a well maintained AC system costs less to operate than one that is not. You may even get your money back in energy savings. A little time and a few dollars may be all it takes to keep your air conditioning in tip top shape for many years.  Be proactive!  Once your AC starts to malfunction, it is usually not cheap to fix.

Professional AC Maintenance

Again, if you are not comfortable doing any of these tasks, then have a professional do it for you. It may cost you a few dollars now but it may save you a small fortune in the long run. If you do have a professional check your system, make sure they do the following:

• Check for proper refrigerant levels. A low level indicates a leak that needs to be found and repaired before adding more refrigerant.

• Check all electrical components and controls.

• Clean evaporator and condenser coils, as needed.

• Oil motors as needed.

• Calibrate the thermostat.

• Check the condenser.

• Check the filters.