Maintain air conditioner and you’ll stay cool

In the last few weeks summer has taken hold. Temperatures have been consistently in the high 90s and that means that our air conditioners are working hard. The last thing anyone wants right now is for their air conditioner to stop working.

The best insurance against a failed air conditioning system is proper maintenance. Although many parts of your air conditioning system are technical, requiring that maintenance or repair be performed by a trained, licensed technician, there are some things that a homeowner can do to make sure that you stay cool all summer long.

1. Change filters regularly: Making sure your filter is clean is even more important in the cooling season than in the heating season. A dirty filter can restrict air flow across the evaporator coil, allowing the coil to freeze. A frozen coil will stop the system from cooling properly. In the worst case, a frozen coil can damage the cooling equipment, resulting in expensive repairs.

The best practice is to change or replace filters monthly.

2. Clear the area around the condenser: The condenser is the outside unit and it is constantly circulating air through itself (across the condensing coil). Bushes and other obstructions should be kept clear of the condenser to allow this air to flow. Any obstruction of the air flow will have a negative effect upon the efficiency of the system.

Along the same lines, the coil in the condenser must be kept clean. Occasionally I find that a dryer vent discharges close to a condensing unit. Dryer lint will clog a coil fast. If this is the condition at your house you should consider relocating your dryer vent.

3. Keep condensate drains clear: Most of us know that water constantly drips out of a pipe next to the condensing unit when our air conditioners are operating. Where this water comes from, however, is often a mystery.

The answer to this mystery is really quite simple. The Freon in your air conditioning system is very cold when it runs through the evaporator coil (coil above or next to the furnace).

Moisture condenses on the cold coil. This condensed moisture is collected in a pan under the coil and directed to a drain that typically discharges next to the outside unit (condenser). This drain is the condensate drain.

During the winter when the air conditioning system is idle, fungus can grow in the condensate drain. If the drain is clogged with fungus, the condensate can back up and cause a flood around the furnace. In many cases, there is a small, open vertical section of pipe in the condensate drain near the furnace.

Pouring a cap of bleach into this pipe yearly can help keep the fungus from growing. If your furnace is in a basement or crawl space you may have a pump that pumps the condensate up and out. A cap of bleach can also be poured into the pump to keep fungus from growing.

4. Keep an eye on secondary drains: If your furnace is located in the attic, there is also an evaporator coil in your attic. If a condensate drain backs up in your attic the consequences can be severe. In extreme cases this can result in a collapsed ceiling.

To avoid this, furnaces with evaporator coils in attics are required to be installed in a pan. The pan must have a secondary drain. The drain is required to “discharge to a conspicuous point of disposal to alert occupants in the event of a stoppage of the primary drain”.

Often the secondary drain sticks down out of the eave, typically above a window, but homeowners may be unaware of its function.

You should locate your secondary drain and keep an eye out for water dripping from it. Water dripping from the secondary drain means the primary drain is clogged. If you cannot find a secondary drain from your overflow pan look for a small device in the pan. This device is a float switch and it will turn the air conditioning system off if the overflow pan starts to fill with water.

Do you have a home repair question? Send an e-mail to Ask the Inspector at H&G@ajc.com. Our expert, Bill Garwood, spent 15 years as a building contractor before becoming a home inspector in 1990. He is part owner of a residential inspection firm and a company providing training in building inspection and codes.