It seems like it’s been hot for months here in Chattanooga, and it has! Temperatures started hitting the 90s back in May, and a series of heat waves has made 2022 one miserable summer. The last thing you need is your HVAC system to break down. Do you know the top causes of AC failure and how to prevent them?

Common Causes of AC Failure

The good news is that you can prevent most causes of AC failure.

Air filter clogs

A dirty air filter is the most common cause of AC failure.

When the air filter is dirty, the airflow into the machinery is restricted, as well. This puts an additional strain on the blower fan to move air, which overworks the blower motor, causing it to burn out more quickly.

If you haven’t changed the filter lately, this blockage may be the reason your AC has failed.

One of the primary jobs of your HVAC air filter is to protect the equipment itself. The filter media traps particles that would otherwise coat the surfaces of the equipment.

This particulate matter interferes with your AC system in several ways. It causes friction on moving parts, such as the motor. When dirt cakes your evaporator coils, it prevents efficient heat exchange. It can even cause it to freeze up.

That brings us to the next common cause of AC failure.

Frozen evaporator coils

Poor airflow is often the cause of frozen coils. When dust coats the air filter, air can’t flow easily through the system. This prevents cold air from being moved and distributed through your home.

The temperature in the coils drops so low from restricted air movement that they freeze up. Condensation normally forms on the coils when they remove moisture from indoor air. The coil temperature drops, and condensation freezes on the surface.

To rectify frozen coils, you’ll need to turn the entire system off until they defrost. This can take up to 24 hours. This is not a pleasant way to spend a day in August.

Once defrosted, the evaporator coils need to be cleaned before you restart the system.

You’ll find that there are several causes of restricted airflow that freezes evaporator coils. A dirty air filter is the prime suspect. However, blocked intakes, closed vents, and a burnt-out or poorly functioning blower fan could also be a culprit.

Thermostat problems

Modern thermostats use Wi-Fi signals or multiple programming steps to operate. If you’re using a Smart thermostat, first make sure it’s receiving an adequate Wi-Fi signal from your router. Then, make sure it’s set properly to your preferences.

Another simple thermostat problem that many overlook is that they often need new batteries.

Faulty blower fan

It’s a fact of life that mechanical parts will wear out with time. The blower fan in your AC unit is subject to this wear and tear. Worn out blower fan belts or poor fan maintenance causes AC failure.

A trained technician can quickly replace worn belts, lubricate the moving parts, and ensure the fan speed is correct for your system.

Electrical issues

Electrical issues that could cause your AC to fail run from a blown circuit breaker to corroded connections. If your AC fails suddenly, out of the blue, it may be a blown breaker at your electrical panel.

The demand for electrical power is extremely high during a heat wave – so much so that local electrical companies have asked residents to turn their thermostats up to 78 to prevent brown outs.

Check your breaker panel if you get a sudden failure of all parts of the system. If you suspect corroded connections, call your HVAC tech for service.

Blocked condensate drains

The condensate mentioned above must be drained away to prevent AC failure. Along with freezing on the coils, the accumulated water raises the humidity in your home. This can make it feel like your AC isn’t working at all. It also contributes to evaporator coil freeze.

Check your condensate pan to ensure it isn’t overflowing and the drain isn’t clogged.

Low refrigerant levels

The refrigerant in your AC system is designed to absorb and remove the heat from your home. If the level of this chemical is low, there is likely a leak in your system.

It’s also a hazardous material, so any leak must be repaired immediately before your system can be recharged. It must also be repaired and charged by a trained technician.

Extreme heat isn’t just uncomfortable, it can be fatal. The EPA states that more than 11,000 Americans have died from heat-related causes in the last 40 years.

Make an appointment today with One Hour Heating & Air Conditioning in Chattanooga today and let the AC experts ensure that you don’t have to suffer through AC failure.