5 Reasons Your AC Isn't Turning On (and How to Fix It)

Before You Call a Technician: Quick Checks Anyone Can Do

An air conditioner that won’t power on might have a simple explanation. Before you call a pro, first perform some basic AC troubleshooting.

• Confirm whether any indicator lights are on. If any lights are on, the appliance is drawing power, and the problem has some other cause.
• Make sure that the power cord is fitted securely into the outlet, and check that the breaker wasn’t tripped. If necessary, reset the breaker at your home’s electrical panel.
• Depending on the type of system, an air conditioner not working could be because of a flipped maintenance or emergency switch. Even a window unit may be plugged into an outlet controlled by a wall switch. If your AC is switch dependent, check that the switch is in the “on” position.
• Check the temperature controls. The thermostat should be set to “cool” and the programmed temperature below the current air temperature of the room. If the thermostat is unresponsive, check the batteries or wiring.

If you still can’t turn the cool air on, proceed to investigating the condensate drain line for a clog, replacing or cleaning the air filter, or checking internal electrical components. Depending on your appetite for DIY work, you may need the help of a technician.

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5 Reasons Your AC Isn’t Turning On and How to Fix Each One

While an air conditioner can fail for any number of reasons, there are five issues in particular that account for most malfunctions.

1. Tripped Circuit Breaker

The problem: ACs use a lot of power, especially upon startup when the compressor engages. If there are too many appliances drawing power from the same circuit, or if there’s a power surge, the breaker may trip as a safety measure.

How to solve it: Reset the breaker at the electrical panel to restore power. Move the tripped breaker from the center position to “off,” then flip it back to “on.” If the breaker continues to trip and you aren’t overloading the circuit with too many appliances, have an electrician troubleshoot.

2. Faulty or Miscalibrated Thermostat

The problem: An unresponsive or bad thermostat stops you from controlling your air conditioner. It’s also possible that the thermostat is functional, but the settings need to be checked.

How to solve it: Confirm that your thermostat is set to “cool” and the desired temperature is cooler than the current room temperature. If you have an AC not responding to thermostat inputs, check that the batteries or in-wall wires are in good condition. If your home uses a smart thermostat, confirm that it’s connected to Wi-Fi. You can also reset the thermostat per the manufacturer’s recommendations.

3. Condensate Drain Line Clog

The problem: The moisture that an air conditioner extracts from the air flows out of the appliance through a condensate drain line. Over time, this line can become clogged with algae, mold, or fine debris, causing water to back up into the drain pan and triggering a float switch that shuts the system down.

How to solve it: Confirm a clog by examining the indoor end of the drain line and checking the drain pan for pooling water. Use a wet/dry vacuum at the outside end of the line to clear the obstruction.

4. Bad Capacitor

The problem: An AC’s capacitor delivers a charge to jumpstart the compressor and fan. If it fails, the AC can’t function properly.

How to solve it: Replacing a capacitor can be a dangerous job because the component stores an electrical charge even when the appliance is powered off. It’s best to leave the work to a professional.

 5. Faulty Contactor

The problem: A contactor is a specialized relay switch that receives a low-voltage signal from the thermostat and turns on the high-voltage power to the compressor and fan motor. When a contactor corrodes or becomes stuck in the open state, the AC won’t work.

How to solve it: A faulty contactor needs to be replaced. The component itself is not particularly expensive, but there is again the risk of electric shock because of the nature of the work. Calling a technician is the best move.

What Each AC Component Does When It Fails to Start

Understanding how the various mechanisms in your AC system fail can help you resolve a breakdown more quickly and effectively.

• Breaker: A breaker is essentially a failsafe to break the flow of electricity when a circuit is overloaded. If an AC fails to start, it could be because there was a fault or power surge on its circuit. This would trip the breaker, cutting power to the appliance.
• Thermostat: The thermostat is your point of control for the AC. It measures the temperature in your home and signals when the compressor and fan should engage to initiate cooling. If the thermostat isn’t receiving power, then it can’t communicate with the AC unit. If it’s miscalibrated or incorrectly registering the room temperature, the AC won’t turn on at the appropriate time.
• Capacitor: The capacitor gives a boost of energy to start the compressor and fan motor. Much like a battery, it needs to be replaced after some time because it just doesn’t deliver the power the AC needs to get going.
• Contactor: A contactor is a switch that facilitates the delivery of high-voltage power to the compressor when closed, or in the “on” position. A contactor can be the reason for a dysfunctional AC when the switch is stuck in the open position or when it’s corroded enough to impair the flow of electricity to the compressor.

How to Prevent Your AC From Failing to Start in the Future

Some routine AC maintenance will help you go longer before experiencing a breakdown. Here are the basics:

• Clean or replace the air filter every one to three months.
• Check the outdoor condenser unit weekly and after storms to keep it free of leaves, twigs, and other debris.
• Flush the condensate drain line every so often to prevent clogs.
• Schedule an annual HVAC checkup with a professional technician.
• Monitor the system for leaks, strange noises, off smells, and signs of corrosion or deterioration.

But remember that your home warranty provider can advise on whether repair or replacement is the best course of action. All you need to do is make a claim when you experience a breakdown, and you can have a technician diagnose the problem and recommend next steps. To learn more about Liberty Home Guard’s award-winning service, call (866)-983-0940.