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Top 4 Reasons Your Air Conditioner Isn’t Working

Oh, fantastic. You’re sweltering on a hot day and no matter how low you set the thermostat, your air conditioning system just can’t seem to cool the house. Or maybe you feel warm-ish air coming out of the vents instead of nice cold air. What could be going on?

There are many possible reasons why your air conditioner isn’t working, but here are the four most likely ones.

1. Refrigerant leak

When most people think about their air conditioner, they think that cool air is being created. In actuality, the job of the air conditioning system is to collect heat from inside the home, move it outdoors and release it.

Have you ever driven past a construction site and seen a line of dump trucks carrying dirt away as they clear the land? One by one the trucks are loaded, filled and then driven away to be dumped at another location.

In the same way that a dump truck is used to haul dirt from one place to another, refrigerant is used in the air conditioning system as the container to move heat. Each pound of refrigerant is designed to carry a certain amount of heat outside and release it. A system that doesn’t have enough refrigerant will not be able to cool the house properly or at all.

Symptoms of low refrigerant are:

  • Blowing warm air
  • Poor performance (“I have my stat set at 70 and I can’t get the house below 75!”)
  • Icing on the refrigerant line

If you previously had enough refrigerant and now the level has dropped, there is a leak that must be addressed.

2. Failed capacitor

Your air conditioning unit requires more energy to start up than is available through your home’s wiring. A capacitor is added to the circuit to give the unit an electrical jumpstart. Your system contains several capacitors that help start the compressor, outdoor fan motor, and blower motor inside. The most common capacitor to fail is the compressor motor run capacitor.

Capacitor failure is very common but inexpensive and quick to repair. Since it is a very common repair, service technicians stock these on their trucks. Most capacitors fail simply due to age. The life expectancy can vary, but the typical rating is about 5-7 years.

3. Failed contactor

A contactor is a small device that controls the flow of electricity to your air conditioner’s components. Think of a contactor like a drawbridge. When the drawbridge is down, cars can drive freely over the bridge to the other side. When the bridge is up, cars have to wait until it is lowered again.

Contactors work in the same way but instead of controlling traffic, they control the flow of electricity. When your air conditioner is not in a cooling cycle, the contactors are in the “up” position blocking the flow of electricity. When the thermostat wants to start a cooling cycle, a small voltage is sent to the contactors that tells them to lower into the “down” position. Contactors will stay in the down position until the thermostat is satisfied.

Contactors typically fail due to age and normal wear and tear. Like the capacitors, failure on this component is very common but can be repaired quickly.

4. Lack of maintenance

Probably the most common reason for air conditioner failure is lack of maintenance. Like any piece of machinery, your furnace and air conditioning system requires maintenance.

Here are some common consequences of poor maintenance that can leave you without cold air or with a higher-than-normal cooling bill:

Plugged filters

As air from your home blows across the evaporator coil, heat is absorbed by refrigerant and delivered outside. If the filter is plugged and air flow is restricted, it will cause the coil to freeze and leave you without air conditioning.

dirty air filter

Plugged condensate drain lines

In addition to cooling, your air conditioner removes humidity from the air. This water is removed through a small drain pipe and deposited in a floor drain or outside. Left unmaintained, over time this drain can form a clog. The clogged drain can cause the excess water to backup and cause damage to your furnace or property.

Plugged condenser coils

Heat removed from the house is taken outside and released. If the outdoor coils are not maintained and kept clean, your system will be very inefficient. The unit’s inability to release heat will cause the system to run much longer and do a poor job of cooling the home.

Let the pros at Althoff take care of your AC system before there’s a problem.

If it’s been awhile since you’ve had your AC system checked out or maintained, do yourself a favor: Get it done before you’re left without cold air on a hot day. Our licensed Chicago HVAC technicians can take care of your AC tuneup or get you set up on a regular maintenance plan for peace of mind. If you’re experiencing a problem now, give us a call and we’re on it! Contact us at 800-225-2443 to schedule.

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