Why Won’t My Air Conditioner Turn On
Tips & Tricks

Why Won’t My Air Conditioner Turn On?

Your air conditioning system is essential to your comfort, especially during summer. Therefore, if it doesn’t turn on during this season, you will likely go straight to panic mode. 

An air conditioner that won’t turn is quite a common problem; however, there are easy and quick steps you can take to understand why your system is experiencing problems. 

Here are some of the most common reasons why your unit won’t turn on:

Clogged Air Filter

Changing air filters regularly is a task that you should prioritize; however, most people hardly do it. Clean air filters ensure proper airflow; however, the air is often obstructed when they’re full of dust and debris. 

When an AC works properly, it absorbs humidity from your home. Water droplets then fall into a condensation tray and drain outside through the drain lines. However, when your air filters are dirty, the water droplets will freeze and cover the coils with layers of ice. 

Circuit Breaker Tripped

Your circuit breaker might trip if you’re using too many appliances simultaneously. It can also happen when there are power surges after a storm. So first, find your electrical panel and check the AC switch; if it’s in the “OFF” position, switch it to “ON.”

If the circuit continues tripping several times, don’t try and switch it back on. The circuit might be overloaded, and switching it on might cause an electrical fire. Instead, it’s prudent to call an electrician immediately to inspect it. 

Problem With the Low Voltage Wire

If your AC isn’t turning on, there might be a problem with the low voltage wire. This wire often helps send power from your home’s electrical system to the A/C unit. 

If the wire becomes damaged or disconnected, it might prevent the unit from starting. 

Thermostat Issues-Why Is My Thermostat Not Turning On AC?

Your thermostat helps you communicate with your AC; therefore, if it’s not working properly, there’s no way for your AC to know that it should be switched on. 

First, look at the screen on your thermostat. If your thermostat is off or showing a blank display, try to switch it on. If it doesn’t turn on, it might also be a case of dead batteries; therefore, be sure to replace them in the thermostat.

If your thermostat still doesn’t switch on, it could signify that you need a new one. You will need a professional technician to come in and take a look at it because it might have an electrical problem. 

A Blown Fuse

The fuse box is located outside your home, near the condenser unit. It’s best to turn off your AC and power supply before locating the fuse box. 

Once you locate it and turn off the power supply, pull out the fuses and do a continuity test with a multimeter. If one of the fuses isn’t working, you can buy a new one from online retailers or a hardware store. Ensure you take a picture to have the correct model before making the purchase. 

Condenser Unit Is Unplugged

It’s best to visually inspect the cord from your AC because it might not be plugged in, especially if you have a window AC. In most cases, a small brown cord will come from your AC connected to a panel on the side of your home.

These wires can be chewed through or unplugged, stopping electricity flow to your AC and preventing it from switching. 

Clogged AC Drain Line

Failure to maintain your AC regularly will cause it to become overloaded with moisture and eventually clogged with gunk. You can keep your condensate drain line clean by pouring a cup of boiling water down your drain pipeline every month. 

Before cleaning the drain line, turn off the power supply and AC first. 

Refrigerant Leak

There are telltale signs indicating that you have a refrigerant leak before your AC stops turning on. Some indicators include a hissing sound, unexplained high electricity bills, or if the AC isn’t cooling your home anymore. 

You should attend to a refrigerant leak immediately because failure to do so could lead to refrigerant poisoning. However, it’s best to understand that only certified technicians can purchase certain refrigerants; therefore, you might have to call an HVAC professional to perform this task.

AC Motor Failure

The capacitor charges your AC’s motor. If your AC is older than 15 to 20 years, a faulty capacitor may be to blame if it doesn’t turn on. 

You can use a multimeter to determine if you’re dealing with a faulty capacitor. Before testing the capacitor, please turn off the AC and its power supply. 

In addition to the above causes that might lead to your AC not turning on, here are some frequently asked questions about AC not turning on: 

My Window AC Has Power But Won’t Turn On

Window air conditioners are great for cooling a room, not a large house. In addition, they are relatively inexpensive given their cooling power and can last longer if maintained properly. 

There’s nothing more frustrating than a window AC that won’t turn on, especially on a hot summer afternoon. Here are some of the reasons why yours might fail to turn on and possible solutions to the problem:

Dirty Fins and Coils

Your window AC requires regular maintenance to ensure that it works well; after all, it’s a machine. First, ensure that you clean the coils and cooling fins through which refrigerants flow because they’re narrow and tend to trap dust and debris. If the cooling fins or filters are dirty, the insufficient airflow can cause the unit to fail to turn on. 

Additionally, be sure to change air filters since doing so will extend the time between coil cleanings because there will be less dirty air making it through the AC. 

Power Problems

Unlike a central AC, that’s hard-wired into your home’s electrical panel, a window air conditioner plugs into a wall outlet somewhere near the window. So if the unit doesn’t turn on, your first step should be to ensure that it’s plugged in and the power cord isn’t damaged.

Your circuit breaker could also be overloaded and tripped, cutting power to the window AC. You can reset the circuit breaker and ensure that you double-check the required amperage for the AC to ensure that your breaker can supply the proper current.

It’s best to avoid using an extension cord with a window air conditioner as it can increase the load on the circuit, causing the circuit breaker to trip. 

Low or Leaking Refrigerant Charge

Your window AC’s refrigerant is meant to be in a closed system because refrigerants can harm the environment. If you suspect a refrigerant leak, it’s best not to troubleshoot it yourself. Instead, find a specialist with an Environmental Protection Agency (EPA) refrigerant repair certification who can safely trace and repair leaks.

Thermostat Clicks, But AC Does Not Turn On

The thermostat clicking before the AC turns on is a comforting sound, reassuring you that cool air is on the way. Therefore, hearing the clicks with no result can cause alarm. These are some of the common reasons why your thermostat clicks but AC does not turn on and possible solutions:

Clogged Air Filters

Clogged air filters are one of the reasons a thermostat clicks, but the AC does not turn on. A filter cleans the air before circulating through your home, trapping pollen, dust, and dirt particles. Over time, the contaminants will clog the filter, limiting airflow to the furnace or HVAC system. If the airflow is restricted, it becomes harder for the system to generate heat or cool air. 

If you want to avoid this problem, replacing the air filter every 60 to 90 days is best. Afterward, invest in a high-quality model that can screen out a range of particulates.

Check the Capacitor

A faulty capacitor might be why you hear the thermostat click without the AC turning on. The capacitor works as a battery; it stores the electrical charge that starts the compressor at the thermostat’s signal for cool or warm air. 

A defective capacitor is likely to be the problem if you hear a buzzing noise and your thermostat clicking. The buzzing sound can also be the sound of the compressor trying to start without the necessary electrical charge. 

It’s best to call a professional to address any capacitor concerns because its stored voltage can cause an electrical shock when handled incorrectly.

Check the Thermostat Settings

You might want to look at your thermostat settings when it clicks, but the AC does not turn on. If you want the AC to turn on, the thermostat’s set temperature should be low enough to trigger the system to start. 

Additionally, ensure that the set temperature is high enough if you want the heat to come on. It’s best to remember that if the room temperature matches the thermostat setting, neither the heat nor the AC will turn on. 

It’s also advisable to ensure that the thermostat is seasonally adjusted to the HEAT or COOL option. Also, check the fan to ensure it’s set on AUTO or ON for proper airflow. 

Malfunctioned Thermostat

Your thermostat may have malfunctioned if you’ve adjusted the settings and changed the air filters, but the AC doesn’t come on. You can do the following to determine if your thermostat has malfunctioned:

  • Check the thermostat’s wiring, tighten any loose relay connections, and assess for any signs of damage.
  • Turn the thermostat’s breaker off your home circuit breaker box, and wait for a minute or two before turning it back on. It might be faulty if it doesn’t start up at all or properly.
  • Evaluate any new sounds. If the thermostat is clicking louder than usual and all other systems are functioning normally without unusual noises, the thermostat is likely malfunctioning.

It’s advisable to have a technician address any thermostat-related issues. 

AC Won’t Turn On, But Fan Does

Your AC might fail to turn on, but the fan does due to the following reasons:

Insufficient Power Supply

When only the fan can operate, your AC is probably not receiving enough power to turn the compressor on. 

There might be a problem with the wiring or connection, or the circuit breaker might have been the culprit. 

It’s also best to check your thermostat as it might send the wrong signal to the unit itself, making the compressor fail to turn on. 

Damaged Compressor

One of the telltale signs of a damaged compressor is your AC blowing warm air or only capable of being in fan mode. Unfortunately, these are symptoms of an old AC; the best solution is to purchase a new unit.

While you can replace the compressor, most HVAC professionals are usually against it since the repair cost is just as or more expensive than buying a new AC unit.

Broken Capacitor

When dealing with a broken capacitor, your compressor might fail to start up, resulting in hot air being blown out. This is because the compressor needs a specific amount of power to operate, and a broken capacitor will fail to deliver that. 

Dirty Coil and Filters

Dust and dirt buildup can clog your AC’s airflow. When this happens, the compressor will work unnecessarily hard without achieving the desired results, ultimately causing it to shut down when pushed too far.

The compressor might shut down before it gets permanently damaged; therefore, you might get the chance to clean your condenser coils and filters.

Split AC Not Turning On

If your split AC is not turning on, you should check and do the following:

  • First, check if there’s a power supply to your split AC. If there is, ensure that the thermostat is set to the ‘cool’ mode.
  • Next, confirm if all the external wiring is intact because mice and rats could nibble up wires and disconnect the circuits.
  • Check if the electrical wiring of your home is okay. Resetting the power should help you deal with issues related to tripping or blown fuses.

If the above options fail, your split air conditioner might have internal issues related to motors or wiring. In such a situation, it’s best to look for an HVAC technician to help sort the issues. 

Outside AC Won’t Turn On

Your outside AC might not be working due to a couple of reasons. Here are some of the reasons and possible solutions:

Thermostat Is Off or Not Set to Cool

If your outside AC won’t turn on or is not cooling, the first step should be to examine the thermostat and see what temperature it has been set to.

Someone in the household might have raised the temperature or turned off the thermostat entirely. If it’s off, turn it back on, ensure it’s set to cool, and change the temperature to five degrees lower than what the ambient temperature of the room feels like. If the room eventually starts cooling down, there most likely isn’t an issue with the outside AC unit.

If the AC still doesn’t seem to work and the thermostat is battery-powered, you can try replacing the batteries with fresh ones. It’s also advisable to contact an HVAC professional to examine whether pets have chewed through the wires inside the wall or if the wiring has crossed. 

The Shut-Off or Emergency Switch Might Be Flipped

The sources of power that your outside AC use could have been accidentally turned off if it’s not working. Your outside AC has a different power source than the indoor one; therefore, go outside where the unit is located. You should find a place that houses an emergency or shut-off switch next to the unit. 

Someone might have left the switch in the ‘off’ position accidentally. Ensure that everything is plugged in and the switch is in the ‘on’ position before going inside to see if the problem has been fixed. 

There might also be a reset button on the outside AC unit that you can push. You can use the indoor system to reset both units if you find none. Please turn off the thermostat or the breaker and wait for at least a minute before turning it back on. After resetting, confirm if the outside unit powers back and the room is cooling down. 

Check the Capacitor

If the capacitor fails, you might hear a buzzing noise from your outside AC unit. The noise is present because the AC condenser fan is trying to spin without power from the capacitor. 

Capacitors age and wear over time, causing them to fail. However, extreme heat, overwork, or power surges can speed up the aging and wearing process. 

You can test if the capacitor fails by attempting to spin the condenser fan using a thin piece of wood to avoid pinching fingers. If you have a dual-run capacitor and the AC fan starts spinning, there might be dust or debris in the AC fan motor, or the AC fan motor may be damaged. 

You can tell if your capacitor has failed if the AC fan doesn’t spin. 

A Blown Fuse

A blown a fuse to the circuit breaker might have caused the outside AC unit to stop working correctly. A blown fuse is often caused by an overloaded circuit breaker, which happens if the wires are loose or aging or if the unit is overworked. 

Head to your home’s circuit panel and confirm if any breakers have tripped. Next, turn them off and then back on again. You might be dealing with an electrical problem if the breaker immediately trips once it’s turned back on. If this s the case, you’ll need an electrician to access the situation.

It’s best not to turn the circuit breaker back on again because it could cause damage to the AC and other household appliances. If your home has a fuse box, replace any fuses that appear to have blown. Your home’s AC unit might also have its shut-off box. If the fuse is blown there, you might have to contract an HVAC professional to replace it. 

Your AC Might Be Low on Freon

Freon is a chemical refrigerant that cools hot or warm air from outside before entering your house. It runs through a closed loop within the home; therefore, if your unit is low on Freon, there’s most likely a leak within the system.

Signs of a leak often include warm air from the vents, ice buildup on the outside AC, and a hissing noise near the AC. 

The Condensate Drain Line Might Have a Problem

An AC condensate line eliminates the water built up when the AC’s evaporator converts refrigerant from liquid to gas. However, algae and grime can build up in the drain line if it’s not cleaned frequently. 

The line can also get clogged due to high humidity. Once it’s clogged, the line trips a safety switch, which turns the AC off. If you want to unclog the condensate drain line, turn off the HVAC unit and use a dry or wet vacuum to clear what’s clogging the drain. 

If the problem persists, seek help from an HVAC professional to minimize damage. 

Check the Air Filter

If your outside AC doesn’t turn on, check your air filter. It blocks airflow into your HVAC system when it becomes clogged with dust, hair, and other particles. This problem can cause the equipment to overheat and shut off. 

Several reasons might cause your AC not to turn on or stop working correctly. While you can resolve some of the issues, be sure to consult an HVAC professional to assess the situation and help you restore your system to normalcy.