What to Do Before the Air Conditioner Goes On

Written by Chad Humphrey, owner of Humphrey Heating and Air
Updated March 27, 2015
Inspect your air conditioning system’s outdoor condenser unit and remove any objects or vegetation within 18 inches of the unit to ensure proper air circulation. (Photo courtesy of Angi member Andrew B. of Boston)

Follow this checklist before you fire up the AC to keep cool all summer long.

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Your home can be a sanctuary from the heat with a properly functioning air conditioner. But before you fire it up on that first sweltering afternoon, take the time to inspect your system. Following these tips will help you to get the most from your central air system and keep it running efficiently all summer.

Before you turn on the air conditioner

● Walk outside and take a look at your air conditioning system’s outside unit. This is called the condenser. If you covered the condenser over the winter, make sure to remove the cover before you turn it on.

● Remove any objects or vegetation within 18 inches of the unit. It’s not a bad idea to take a hose and spray off the coils. Use a hose with a nozzle and spray the coils at a 45-degree angle to remove debris between the fins.

● Back inside the house, check the filter for the air conditioning unit. Homeowners often overlook the inside part of the central air system, and this is where many problems begin.

Changing the filter regularly is the best thing you can do for your central air system. Change it once a month in the summer and use a pleated filter.

Before you turn on your central air system for the first time, make sure you have a new filter in place and that there are no gaps where the air can pass unfiltered.

● Now that you have inspected everything, it’s time to make sure the breaker and/or disconnect switch to the condenser is turned on. After this is done you might want to close all the basement vents. You will want the air from your system to be concentrated on your middle and upper floors, where it is needed the most.

Let’s fire it up

● Now that you have prepared your central air it’s time to flip the switch. Turn your thermostat to “cool” and turn the fan to “auto.” Turn the setting down to 68 degrees or so for the purpose of these next steps.

● Once you hear the system come on, go back outside to the condenser and make sure the fan is spinning. You also should hear the hum of the compressor.

● Walk back inside. Listen for anything abnormal with the furnace blower. Should you see or hear anything unusual, turn the system off immediately.

It’s running, but is it working?

One basic check that a homeowner can do to determine if the central air is operating properly is to examine the copper refrigerant pipes. The large one, which is usually insulated, should be cold.

While the system is running, go outside to the condenser and push up the insulation a little bit to expose the pipe. Put your hand around it to check if it’s cold. (It should feel like a soda can that you just took out of the refrigerator.)

You will often see condensation on this refrigerant line. That’s a good sign that the refrigerant level is where it should be.

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What to watch for

As the temperatures outside start to rise, your central air will be running longer and working overtime.

● Watch for water on the top or under your furnace. Condensation is normal, but it should run through the condensate drain only.

Damage caused by improper drainage is common and usually expensive to repair. Look for any signs of freezing on the large copper line. If you see ice or frost there, it may be a sign that you have low refrigerant or improper air flow.

● If your central air system runs all the time and rarely shuts off, or you can’t get the temperature below 75 degrees, you may have a problem with the system.

● High power bills also can be an indication that something is wrong with your air conditioner.

If you see signs of trouble, you may need a professional to take a look at your system. Being proactive means you won’t have to worry about your air conditioning calling it quits on a 100-degree day this summer.

RELATED: How Often Does an Air Conditioner Need Service?

A version of this article appears on the Humphrey Heating and Air website.

Chad Humphrey is the owner of Humphrey Heating and Air. Started in 2004, Humphrey Heating and Air earned the Angi Super Service Award in 2013 and provides HVAC services in Bountiful and Salt Lake City, Utah.

As of March 27, 2015, this service provider was highly rated on Angi. Ratings are subject to change based on consumer feedback, so check Angi for the most up-to-date reviews. The views expressed by this author do not necessarily reflect those of Angi.

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