How To Prepare Your Air Conditioner For The San Marcos Summer

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If you have air conditioning in your San Marcos home, you may want to check your air conditioning system to make sure that it’s ready to handle the upcoming summer’s heat. The last thing you want is to turn on your air conditioner on a hot summer’s day and find that it doesn’t work! Here are some cleaning and maintenance tasks that will help to ensure your air conditioner is operating at some degree of efficiency:


Once an air conditioning system is correctly installed and charged, the accumulation of dirt in the system is the single biggest contributor to loss of air conditioner efficiency. Dirt insulates against good heat transfer and restricts adequate air flow. To boost your air conditioning system’s efficiency, improve airflow, clean or replace the filters when dust begins to accumulate. Disposable filters should be replaced at least as often as the manufacturer recommends. Filter area should be a minimum of one square foot per ton of air conditioning. Great air filtration is a balance between filter area and a filters restriction to air flow. Two to eight inch pleated filter media strikes a good balance between good air filtration without excessive intake grills. Aprilaire makes several filter variations that work well in the San Marcos area.

Outdoor Condenser Unit

The air conditioning system’s outdoor condenser unit consists of a compressor, fan, coil, and controls. Unlike the indoor coil the air passing thru the condenser coil is never filtered. It does, however, get some cleaning with every rain shower. It also gets lawn clippings and other debris thrown at it on a regular basis. Here in San Marcos, air conditioning condenser coils should be water washed every spring. Heat Pump condenser coils should be water washed every spring and fall.

Before cleaning the condenser unit, turn off power to the unit. You may need a screw driver or nut driver to remove the protective grilles from the metal box if the debris cannot be removed with a good strong water spray.

CAUTION: never use a power washer on condenser coils and be vigilant when washing the coils that you do not bend, flatten or misshape the thin aluminum fins.

A common trick technicians use to quickly evaluate how clogged a condensing coil may be, is to pass a hand all the way across where the fan is blowing out the hot air. The air should be blowing straight up or out at a 90 degree angle from the fan guard. If air is blowing out the edges of the fan guard at 30 to 45 degrees the condenser is very dirty…even if it visually appears clean. At some point it may want to have the condenser professionally cleaned.

Remove any possible airflow restrictions from around the condenser by cutting tree branches, shrubs, and tall grasses. Remove possible air flow restrictors that are three feet from the sides of the unit and eight feet above it.

Refrigerant Lines

The exposed copper pipes that connect the evaporator to the outdoor condenser unit should be insulated on the exterior of the house and in the attic. Replace any missing insulation. Air conditioning units only need the larger of the two lines to be insulated. Additional energy efficiency can be obtained on heat pumps by insulating both lines.

Condensate Drains

Condensate drain lines remove a lot of water here in the San Marcos area, so it is a great idea to make sure the drain line is open every spring. The worst way to clear a drain line is to “blow it out”. The best practice is to use a wet-vac and suck the line clean where it terminates … either outside the house or inside the house under a sink. Before attempting to clear a drain line with a wet-vac, make sure the air conditioning system has been running long enough to cause water to start running out the line. Block the drain ‘air vent’ that should exist at the air handler just past the p-trap. Now when you vacuum the line, the water in the drain pan will wash out the drain pan opening, the p-trap and the rest of the drain line.

If your floors and ceiling are not protected with safety float switches in the primary and secondary drain lines, look into having them professionally installed.

Consider Getting an System Performance Check Up

Avoid spring check-up specials…there’s nothing special about them. Unless you have a checklist and time to follow a technician around you’ll have to take what you get on faith. Most San Marcos HVAC contractors can be trusted but the average 21 point inspection doesn’t tell you or the technician if your SYSTEM is operating correctly. When it’s all said and done all the technician know is that most of the individual components are ok but they don’t know any more about how those components are operating together as a system than you do.

Here’s a test you may want to try. After you have paid for your 21 point inspection and have the receipt in hand, ask the service technician … How many BTU’s should my system be producing? Write down the answer and then ask…. How many BTU’s is it producing? Then have them explain how they reached that number.

I’m a big believer in preventive maintenance programs, I just believe the program should tell the homeowner and the technician how well the SYSTEM is working … not just how well a bunch of components are operating all alone by themselves. A maintenance check should compare how your system is running compared to how it should be running.