Why Is My AC Not Turning On?

thermostat wiring

The thermostat is completely blank

When you try to turn on your air conditioner during the warmer weather months and it doesn’t function normally, you know you need a solution ASAP. And if you’re reading this right now, there’s a good chance you’re already feeling the heat. When you discover your AC not turning on, it’s time to get to the bottom of the issue.

Some of the most common air conditioner problems can be solved with ease. However, for you to have a cool and comfortable summer, you may need an HVAC professional on your side. Today, let’s look at the air conditioning system issues you’re most likely to face when your indoor unit or the outdoor unit fails to turn on.

Tripped Circuit Breaker

One of the most common air conditioner problems is your circuit breaker switching off. If your home has a lot of appliances running at the same time, a circuit breaker may trip and cause your AC unit to stay off. This can also happen after a power surge caused by a storm and even damage your central air system.

Locate your home’s electrical panel and find the circuit breaker that powers your AC unit. If it’s been switched off, switch it back on.

If your circuit breaker continues to trip, it may be overloading. You don’t want to cause an electrical fire, so reach out to an electrician or HVAC specialist on the double.

hvac blown fuse

Blown Fuse

Most air conditioning systems have a fuse box outside the home near the outdoor unit. Before you investigate this issue further, we recommend you turn off your air conditioner and its power supply. After all, the last thing you want is to suffer warm air while being electrocuted.

When you find the fuse box, you can use a simple multimeter to test whether each fuse is in working order. If not, you can usually find a replacement fuse from a hardware store or online. Keep in mind, though, that during the warmer weather months, you may need your cool air conditioning working a lot sooner.

circuit breaker

Dirty Evaporator Coils and Condensers

If your indoor air quality is prone to collecting dirt, dust, dander, or other airborne debris, it can build up on your air conditioner evaporator coil over time. Dirty evaporator coils can make your air conditioner unit less efficient and suffer from catastrophic breakdown if the issue goes unchecked.

Central air systems may not turn on for other reasons, including condenser units being unplugged – especially if you have an indoor unit. Check the air conditioner cord and make sure it’s fully plugged into a power panel inside or outside your home. It could also have been chewed through by an animal or become broken somehow, so keep it safe and secure at all times.

Your best bet is to contact a professional HVAC repair and maintenance team to handle your evaporator coil or condensate line issue.

blown contactor

Wiring Issues

If this isn’t the first time you’ve noticed a problem with your air conditioner system or another appliance in your home, you very likely have wiring issues.

The power supply to your home cannot properly perform its job if the wires carrying electricity to and for are improperly installed. This can lead to power surges, electrical issues, and total power failure if you don’t address the problem quickly.

connected wires on a residential condenser

Clogged Air Filter

When was the last time you changed your air conditioning system’s air filter? Most people understand that their homes may have dirty air filters and know to change them, but everyone is human – in other words, they forget! If you do, you won’t have cold air for much longer!

If your air conditioner’s air filter is dirty, clogged, or damaged, you need to change it as quickly as possible. Many air conditioners may try and fight through a clogged air filter but can overheat themselves and damage your HVAC system in the process – don’t let this happen if you want your AC unit to work year-round.

Faulty Motors

A lot of homeowners have much older AC unit systems powering their central air system. If your air conditioner is older than 15 years old, it could very well suffer from a faulty capacitor. This can lead to a host of issues with most central air systems.

Also, think back a few weeks. Has your air conditioner made any weird noises lately? If so, you may have a faulty motor.

The best way to check for this is a capacitor test, but odds are good you don’t have the equipment lying around to handle this. If this is the case, your best bet is to reach out to an EPA-certified technician who can perform a thorough inspection of your AC problems.

Faulty blower motor in residential split furnace

Refrigerant Leak

Home air conditioners are unfortunately prone to coolant leaks. Your central air system doesn’t need regular coolant changes like your car needs oil changes, but if you have a refrigerant leak, it’ll fail to do its job. In other words, it’ll just blow warm air.

Since refrigerant is responsible for pulling heat out of the air, your air conditioning system may still turn on but won’t be blowing cool air or whatever your desired temperature.

If you have a refrigerant leak or have experienced refrigerant shortages in the past, it may be time for your HVAC system to have a coolant refill. Freon can only be handled by EPA-certified professionals, so find a local expert!

Incorrect Temperature Readings

Your thermostat is possibly the most important element of your HVAC system – without it, you won’t be able to control your air central air system at all. Check it regularly and make sure the screen is working properly. If it’s ever blank, losing battery power, outdated, or broken, you may experience your AC not turning on.

If you’re having issues with faulty thermostats in your HVAC system, you may need a professional HVAC specialist to check and see if you have a faulty thermostat. There’s a good chance it needs to be replaced!

Temperature reader receiving temperature from vent

AC Not Turning On? Call In the Pros

Have you had a problem with your HVAC system not turning on? Whether it’s your evaporator coil, condensate drain line, dirty air filter, safety switch, air supply, circuit breaker panel, or your AC system is no longer pumping compressed refrigerant, you need an air conditioning fix as soon as possible.

To keep your air conditioner working properly year-round, you have to keep it well-maintained. That’s why we recommend having at least two AC unit tune-ups each year handled by professional HVAC specialists. Fortunately, the team at Blue Water Climate Control is ready to help – contact us today to schedule an emergency air conditioner system repair!

Written by Jeremy James

Jeremy is the founder and CEO of Blue Water Climate Control. He is a Navy veteran with 24 years of naval service in the Navy's Nuclear Propulsion Program. He has broad engineering experience having worked on submarines and aircraft carriers. LinkedIn

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