outside ac not turning onDuring summer, a broken air conditioner is more than an inconvenience. It’s an emergency. Homeowners rely on outside air conditioners to remain comfortable in extreme heat. When they malfunction, it’s important to resolve the issue as soon as possible. For anyone struggling with their cooling system, here are the most common reasons why your outside AC is not turning on.

Tripped Circuit Breaker

Circuit breakers control the flow of electricity through your home. When voltage spikes, they trip, cutting power before the wiring shorts out or overloads and catches fire. They’re a safety device designed to protect your property and your family from disaster. Often, when an outside air conditioner won’t turn on, it’s because the unit was drawing too much power and tripped the breaker.

In these cases, all you need to do is flip the breaker back on and the AC will start up again. However, if the breaker trips a second time, you’re likely suffering from a more serious problem. Before calling an HVAC technician, try resetting your air conditioner. Some outside AC units have a reset switch located on the exterior casing, normally along the edge, close to the ground. They’re big, red, and hard to miss.

On the other hand, if yours doesn’t have one, you can achieve the same effect by shutting off the breaker and waiting 60 seconds before restoring power. Sometimes a simple reset is all the unit needs to start working again.

If not, check the air filter and condenser coils. Dirt buildup can cause the unit to overheat and break the circuit. Replacing the filter or dusting the coils should solve the problem. Otherwise, you’ll need to contact an HVAC repairman. The coil fan might be damaged, the compressor may be worn out, or the wiring may have come loose.

Shut Off Switch

Most outdoor air conditioners are equipped with an emergency shut off switch, located in a metal box near the unit. HVAC technicians use it to cut power while they’re working on your AC system. Most of the time they switch it back on before they leave, but occasionally they forget. Check to make sure it’s on. If it isn’t, then you’ve solved the problem.

Faulty Thermostat

The thermostat is the brain of your cooling system, responsible for activating the air conditioner whenever temperatures climb above your programmed setting. When the thermostat breaks, it leaves your outside AC completely inert. Some thermostats are battery-powered, in which case, changing the batteries will get it working once more.

If the thermostat is fully powered, you can test it by asking someone to stand outside by your air conditioner while you switch the thermostat from “OFF” to “COOL.” Both units should make a noise. The one that doesn’t has a problem. If it’s the thermostat, you’ll need to hire an HVAC technician to take a look and possibly replace it.

Broken Capacitors

Capacitors hold the energy your air conditioner needs to power on and continue running. Every outdoor AC unit has two. One activates the motor while the other supplies the energy necessary to keep it going. All capacitors wear out over time, especially if they’re exposed to extreme heat or power surges. If your capacitors have reached the end of their lifespan, the cooling system won’t be able to switch on or run for more than a few minutes.

Homeowners can test their capacitors by inserting a long, thin wooden stick into the top of the unit and pushing the fan blades. (Don’t use a metal one or you might get shocked.) If the blades start spinning, the motor’s not receiving enough power to kick-start the fan, which means the capacitor needs to be replaced.

On the other hand, if the fan blades slow down and stop, the fan motor may have shorted out. If the blades won’t budge, the gears might have gotten jammed or there may be debris wrapped around the axle. Regardless, you’ll have to call an HVAC technician to repair the faulty parts.

Blocked Condensate Line

All air conditioners generate condensation. The condensate line is supposed to drain it away, to keep the AC free of moisture. However, when the condensate line gets blocked, it triggers a safety switch that shuts off the unit before the drain pan can overflow and damage your cooling system.

Blockages generally form for three reasons, all of which can be fixed without professional assistance. First, a piece of debris may have gotten stuck inside, which you can suck out with a dry/wet shop-vac. Second, if the water inside the drain becomes stagnant, algae can develop. However, pouring a cup of bleach or vinegar down the drain should clear it away.

Finally, the water inside the line could have frozen. This normally occurs when the filter becomes too dirty and restricts airflow over the evaporator coils. Evaporator coils get incredibly cold and they rely on a constant flow of warm air to remain balanced.

Without it, their temperatures plummet, freezing the moisture inside the unit. To thaw it out, shut down your AC, replace the filter, and wait for the ice to melt. Once the unit has dried out, it should run like normal. However, if the coils freeze again, you’re experiencing a deeper mechanical problem requiring professional help.

Low Refrigerant

The refrigerant is a working fluid that absorbs heat. It circulates through your air conditioner, transferring heat from the inside of your house to the outside. Running an outdoor AC with low refrigerant damages the compressor, which is why air conditioners are designed to shut down whenever refrigerant levels dip below the recommended pressure.

Refrigerant circulates in a closed loop, so the only way for it to run low is a leak somewhere in the system. Signs refrigerant is the reason your outside AC is not turning on include:

  • Ice around evaporator coils
  • Warm air blowing out your vents
  • Persistent hissing sound from your air conditioning unit

By law, refrigerant can only be handled by a qualified HVAC technician, so if you suspect you’ve developed a refrigerant leak, call an HVAC contractor right away.

Protecting Your Home Cooling System

Repairing a broken air conditioner can cost hundreds or even thousands of dollars. Agway customers, however, don’t have to worry about these types of out-of-pocket expenses because they’re automatically enrolled in our EnergyGuardTM program. It covers them in the event their heating, cooling, or electrical systems break down.

We schedule the repair through our network of local contractors and pay for all covered parts. There are no service fees or deductibles. Your coverage is included as part of your monthly rate. Sign up today to protect your home and finances.