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Why Won’t My Air Conditioner Turn On? A Texas Tech Explains

March 03, 2020

AC Installation in San Marcos, TX

Summers tend to get hot and humid here in Texas, and there’s nothing worse than an AC that won’t turn when you need it the most.

Over the years, we’ve helped fix countless AC systems that wouldn’t turn on, and we’ve found that some of the more common reasons for this issue include:

  • A problem with the thermostat
  • A frozen evaporator coil
  • A faulty/tripped circuit breaker
  • A clogged condensate drain line

In this blog, we’ll take a closer look at these problems and what you can do to get your AC up and running again.

Feel better leaving the AC repairs to the pros? That’s what we’re here for.

Problem #1: A thermostat issue

Think of your thermostat as the brain of your cooling system. Just like a brain, if your thermostat isn’t working correctly or is on the wrong setting, it’s sending the wrong message (or no message) to other parts of your AC system.

To determine if your thermostat is the issue, try these two steps:

  1. Take a look at your thermostat. If the screen is blank, the thermostat could be dead, in which case you should try replacing the batteries.
  2. If your thermostat screen isn’t blank (it’s displaying the temperature), check to ensure that the thermostat is set to “cool” and not “heat”. If you’re just turning your AC on for the summer, your thermostat could still be set to heat, which may be why it’s not turning on.
Cool Vs Heat Setting Thermostat

If you’ve tried both of these fixes and aren’t having any luck, your next step should be to contact a professional. There could be a more serious issue with your thermostat that may require a professional fix

Problem #2: A frozen evaporator coil

AC Dehumidification Process

The AC dehumidification process

Your evaporator coil works to cool your home’s air with the help of a cold liquid called refrigerant (a heat transfer fluid that circulates through the coils).

As the warm air from inside your home passes over these cold coils, the refrigerant absorbs heat from that air, leaving your AC system with cool air that it blows back into your home.

However, if there isn’t enough warm air passing over the evaporator coil, it will begin to drop in temperature. Eventually, the entire evaporator coil will freeze.

Typically, a frozen evaporator coil is caused by:

  • A dirty air filter- Air filters eventually become clogged, which blocks the airflow to the evaporator coil. This blockage causes the coil to freeze due to the lack of warm air blowing over it.
  • Blocked or closed air vents- If your air vents are blocked or closed, your AC will struggle to provide sufficient warm air to your evaporator coil.
  • A refrigerant leak- As we mentioned above, refrigerant is a cold substance that circulates throughout your AC system. If there is a refrigerant leak, there won’t be enough heat circulating through your evaporator coil, which causes it to freeze.

If you think a frozen evaporator coil may be the issue, our suggestions would be to:

  1. Check your air filter and replace it if it’s dirty.

An example of a clean air filter (left) vs. a dirty air filter (right).

2. Be sure that all of your air vents are open and unobstructed.

If you’ve tried both of these suggestions and your AC still isn’t working, you may have a refrigerant leak, which you’ll need a professional to repair.

Problem #3: A faulty/tripped circuit breaker

A circuit breaker is an electrical switch/safety feature designed to automatically shut off the power to the electrical components in your home if the electrical wiring has too much current flowing through it.

Often times a tripped circuit breaker is a direct result of a harmless power surge in the grid. However, if your circuit breaker has tripped or is somehow damaged, then your AC won’t turn on.

To fix this, find your electrical panel and look for tripped breakers. Most circuit breakers have a red or orange color indicator that will show if the circuit breaker tripped. If there is no indicator, look for a switch that has been shifted to the “OFF” position.

Push the switch so that it is fully in the “OFF” position and then switch it to “ON” again. This should do the trick.

An example of a circuit breaker

If the breaker trips immediately after you’ve reset it or a few minutes later, don’t try to reset the breaker again by yourself. In this case, you likely have a short or grounded circuit, which you’ll need a professional to resolve for you.

Problem #4: A clogged condensate drain line

Your AC not only cools your home but dehumidifies it as well. Once warm air blows over the cold evaporator coil, moisture from the air in your home forms on the evaporator coil and collects in the drain pan, located directly underneath the evaporator coil.

The moisture that is collected in the drain pan then exits your home via the condensate drain line.

Now, if your condensate drain line becomes clogged, water will start to back up in your drain pan, triggering your AC’s float switch. The float switch automatically shuts down your AC unit to prevent it from flooding your house.

Clogged condensate drain line

A clogged condensate drain line

Example of a condensate drain line

Example of a condensate drain line

Regular Maintenance services are the best defense against clogged drains. Our technicians clear out your drain line at each maintenance visit, which is typically twice a year, prior to peak summer and winter weather.

Our technicians also check and change your filters, refrigerant levels, electrical components and ensure your system is fully ready for operation.

A maintenance plan also helps keep your system running longer, and keeps you more comfortable in your home year-round.

Need a Texas pro to get your AC up and running again? Give us a call!

We’ve been repairing AC systems all over the state for over 20 years. Everything is bigger in Texas, but our team has never come across a problem too big to handle. We’ll have your AC running like new in no time. No games. No gimmicks. Just Reliable!