Why Isn’t My AC Blowing Cold Air?

The last thing that you want on a sweltering summer day is to turn on your AC and find your air conditioner not cooling. Before you call a A/C repair service, it is important to have a basic understanding of how your air conditioner works so that you can troubleshoot this common issue.

The Basics of AC Operation

All home air conditioning systems operate using the same basic principle. The evaporator, condenser, and compressor work together to extract heat from the air inside your house and recirculate the cooled air through a system of ducts back into your home. The evaporator coils located in the indoor portion of your AC unit use refrigerant to absorb heat from the air that is pulled into the system. The cool air is forced back into the home through the ducts and vents. Meanwhile, the refrigerant, which has been turned into a gas by the heat, travels to the condenser coil outside the home where the compressor condenses it back into a liquid. This extracts the heat from the refrigerant so that it can be released outside of the home. The newly cooled refrigerant is then forced back into the interior portion of the system to begin the cycle again.

Improper AC Thermostat Settings

The first step in diagnosing why  your air conditioner not working is to verify your air conditioner thermostat settings to make sure that they have not been changed accidentally. The thermostat should be set to “auto” instead of the “on” setting. When set to “on,” the fan will continue to blow even when the AC has cycled off. This circulates air through your home but does nothing to lower the room temperature. It also uses more energy, which can run up your utility bill.

AC Not Working: Dirty Air Filter

Your air conditioner needs unrestricted air flow in order to function properly. If your air filter is clogged with dirt and debris, the air flow to your AC becomes restricted. This can eventually cause your condenser to freeze up. At Swan Heating & Air Conditioning, we recommend that homeowners change their air filter every one to three months.

It is important to note that certain high-efficiency air filters designed to remove extremely small particles from the air may cause a similar problem. The filter material can be so thick and tightly woven that it restricts air flow just like a dirty air filter. Be sure to refer to the manufacturer’s recommendations when choosing a replacement air filter for your AC.

Dirty Condenser

Dirt can collect on the outside condenser unit and coils, which can cause your AC not cooling house evenly or even freeze up altogether. The condenser unit and coils should be inspected and cleaned annually to ensure that your air conditioner runs at peak performance. You should also make sure that bushes, weeds, and other objects are not restricting air flow. As a general rule, you should have a least 24 inches of clear space on all sides of the condenser unit.

Low Refrigerant Levels

In theory, your air conditioner should never lose refrigerant since it is contained within a closed system. In reality, wear and tear can cause various components to loosen or weaken resulting in loss of coolant. Without refrigerant, your air conditioner cannot cool the warm air. Low refrigerant levels can also cause a drop in pressure that can cause your AC to freeze.

AC Not Cooling: Defective Parts

A variety of mechanical issues can cause your air conditioner to not blow cold air This is often the case with older AC units. The most common mechanical malfunctions involve the condenser and compressor. The condenser is the portion of the AC that removes the heat from the air. It should blow the warm air to the outside and return cool air into the home. The compressor takes the cool air from the condenser and pushes it to the vents in your home.

AC Not Turning On: Electrical Issues

A variety of electrical issues can affect the performance of your air conditioner. Some of the most common electrical issues that we see include:

  • failed sensors,
  • malfunctioning thermostats,
  • defective breaks,
  • shorted or broken wires, and
  • corroded connectors or contacts.

When to Call an HVAC Professional

If you have verified your thermostat settings, replaced your filter, and made sure that there is nothing obstructing the air flow around the outdoor unit, it is time to call a professional if your air conditioner not turning on or air conditioner is working but not cooling. At SWAN Heating & Air Conditioning, we never recommend that homeowners try to diagnose and repair mechanical, electrical, or refrigerant leak issues on their own. This can cause further damage to your system, invalidate your manufacturer’s warranty, and pose a significant safety risk. Our HVAC technicians are available 24 hours a day for emergency air conditioner repairs.

The best way to ensure that your air conditioner is ready for the demands of the summer cooling season is to schedule an AC tune-up with a qualified service company. We offer affordable annual maintenance plans for homeowners in Loveland, Fort Collins, Longmont and the surrounding areas of Northern Colorado. Our tune-up service includes checks of more than 20 of your AC’s safety and operating features. Call today to schedule your appointment. You can also use our convenient online service request form.

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