Causes of AC Failure
Most central air conditioning systems last for about 12 years before they have a major breakdown. Since O’Fallon, MO, has a lot of hot and humid weather, however, it’s almost always too soon to experience an AC failure. Knowing about the most common causes behind air conditioner issues allows you to take preventive actions. Here are some of the most common reasons why air conditioning systems fail.
Older air conditioning systems use Freon as the chemical refrigerant. Systems made since 2006 usually use R-410-A, an environmentally-friendly refrigerant. A refrigerant leak triggers the air conditioner to have low pressure. The safety switch is triggered by low pressure. If the pressure is too low, the air conditioner will not turn on. A leak of R-410-A could be repaired. The fixtures, hoses, and valves can be checked and replaced by qualified technicians. In the case of a Freon leak, the system should be replaced.
Air conditioners have refrigerant flowing through their coils. The coils are located on the outdoor condenser unit. Those coils need warm air circulating around them, otherwise, they can freeze. A frozen coil stops the flow of refrigerant. When the refrigerant cannot flow into the indoor compressor unit, the system will shut down. The coils can freeze if they are blocked by plants, debris, or soot from air pollution. You may notice ice buildup, icicles, or frost on the outdoor unit. If you see this, your air conditioner needs professional servicing.
Dirty coils can also lead to AC failure. Dirt on the coils impedes airflow. If the warm air from in your home cannot be dissipated to the outdoor environment, the heat transfer is impeded. The air conditioner may attempt to overcome this by cycling more frequently. This leads to overheating of the motor or fan. During an annual AC tune-up, technicians clean the coils to prevent this problem.
Drain Pan or Condensate Overflow
Air conditioners perform two functions. The first is to transfer energy in the form of heat from your home to the outdoors. The second is to dehumidify your home. As the refrigerant in the system absorbs that heat, moisture from your home’s air condenses. This creates liquid water. The water collects in the compressor’s drain pan. The drain pan connects to a pipe that drains into your main sewer line. A crack or clog in the drain pan or condensate pipe could send water up into the air handler or compressor. Clogs usually result from algae growth in the pipe. Water damage will shut down the air conditioning system. A telltale sign of drain pan or condensate pipe problems is a big puddle of water on the floor by the indoor unit.
Blown Fuse or Circuit
A wiring problem, such as a blown fuse or circuit, could also cause your St. Louis area home’s air conditioner to fail. The vibration of the unit could cause two wires to pull apart after years of use. Insulation can degrade when exposed to extreme temperatures. Pests could get into the unit and damage the wiring. A malfunction of the air conditioner’s power or reset switch could result in AC failure. The wiring in your home could also be an issue. A power surge or brown-out could damage the circuit that serves the air conditioning system. A jolt of power from a nearby lightning strike could fry the wiring of your air conditioner.
An overheated motor is also a leading cause of AC failures. The motor powers the fan that allows the super-heated refrigerant to dissipate its energy. This is necessary to prevent the compressor unit from overheating. If the motor overheats, the fan stops spinning. The heat buildup will trigger the air conditioner’s safety switch to trip. Sometimes, the motor will give a few warning signs that it is about to break. Grinding or banging sounds are an indication that the air conditioner needs urgent repair. If the fan is operating slowly or intermittently, this is also a sign of a motor issue.
Dirty Air Filter
While it’s very easy to remedy, many AC failures are caused by dirty air filters. Air conditioning systems mostly use disposable filters made of spun fiberglass, pleated paper or cloth attached to a cardboard frame. Every time the system cycles, the filter captures dust, pollen, hair, skin cells, pet dander, and more. After 30 days of regular use, the filter usually has a light layer of debris. By 90 days after it is installed, an air conditioner filter will probably have a thick layer of debris. It will need to be removed and replaced. Leaving a dirty air filter in the system makes it work harder. This is because the buildup on the filter makes it more difficult for the cooled air to pass through. Your air conditioner will run more frequently. The constant cycling caused by the dirty air filter could overheat your air conditioner and cause excessive wear and tear on the motor and fan.
Closed or Obstructed Air Ducts and Vents
If your air vents are obstructed with vermin, dust or construction debris, the cooled air will not be able to pass through them and into your living spaces. This is also true if the air ducts are loose or if the vents are closed. The thermostat will not register a temperature difference, so the air conditioner will continue cycling. The air conditioner will eventually wear itself out. Its connections or motor may overheat, resulting in a system failure. Avoid storing boxes or putting furniture in front of air vents. Duct cleaning every three years ensures that the air can pass through and inspections identify loose areas, gaps and cracks in the ducts.
Malfunctioning or Broken Thermostat
The thermostat communicates with the control board of the air conditioner. Many different issues with the thermostat can cause the AC to stop working. A dead battery in the thermostat will cease its communications with the air conditioning system. For a smart thermostat, loss of the Wi-Fi connection could shut down the air conditioner. A loose wire or connection within the thermostat causes a miscommunication that may halt the air conditioner’s cycling. Sometimes, thermostats fail. Once each year, replace your thermostat’s battery. It may need replacement every six months if you use the touchscreen a lot to adjust the temperature. This can also be done at your annual AC maintenance visit. If you put in a new battery, and the thermostat is unresponsive, a repair or replacement may be needed.
At Hoff Heating & AC, we employ NATE-certified technicians who are qualified to identify why your air conditioning system is not working properly. In addition to AC repairs, we also offer heating and cooling maintenance, installation and replacement service in O’Fallon and the surrounding areas. To learn more about the causes of AC failure, call us at Hoff Heating & AC today. We’ll help you figure out what’s wrong with your system.