Your AC unit turning on and off repeatedly is one of the most common AC problems homeowners face. It can be caused by dirty, damaged, failing components or electrical and mechanical factors.
If your AC unit keeps turning on and off repeatedly, then it’s probably experiencing short cycling. Short cycling generally refers to a condition where the AC system’s cooling cycle stops prematurely and turns on again after a short while, like every 5-10 minutes depending on the system’s condition.
Short cycling is a typical air conditioning problem that can be costly, especially when not detected early. Fortunately, short cycling is easy to fix: below are some of the reasons why your AC unit turns and off repeatedly and their solutions.
The reason why your AC unit is experiencing short cycling can be as a result of problems with the thermostat. Although a thermostat may seem like a small part of your AC system, it’s essential to your AC system as it controls the temperature. When the thermostat fails to detect the temperature correctly and relays the wrong information, the AC system gets the false signal and starts turning on and off repeatedly. Additionally, if the screen on the thermostat is blank, it could be that the thermostat has low battery power, which can make your AC unit turn on and off continuously.
What to do: You can try changing the batteries of the thermostat and restart it after that. If this doesn’t solve the problem, you’ll need an HVAC expert to examine the thermostat.
Wrong Thermostat Location
A thermostat controls the room temperature and signals to the AC system when to turn on and off. A wrong location of the thermostat can cause inaccurate thermostat readings. Some of the wrong places for a thermostat include: close to a window under direct sunlight, beneath or close to the supply air vents, and close to the hottest room in the house, like the kitchen. These locations can make the thermostat receive inaccurate temperatures and cause it to go on and off repeatedly.
What to do: This is incredibly simple to rectify: simply move the thermostat to a better-centralized location.
Clogged AC Unit Air Filter
When your AC systems air filters are clogged and dirty, it can cause a variety of problems for the system. Clogged air filters can restrict the free flow of air to the AC system, which can lead to short cycling.
What to do: Check if the Air filters are dirty and replace them. It’s essential to change your air filters regularly to avoid more AC problems. If the problem persists after replacing the air filter, you may need to have an HVAC expert check out the other AC components.
Dirty Condenser Coils
Condenser coils are responsible for releasing heat from your home to the outdoor environment. If you haven’t done AC maintenance in years, the condenser would be dirty. Dirty condenser coils prevent hear from escaping, which could make your system overheat and experience short cycling.
What to do: You’ll need to service the AC and have an HVAC professional clean the condenser coils.
Oversized AC Unit
If you just installed a new AC and it’s been short cycling since the day you installed it, the chances are that the AC is too large for your space. When your AC is too large for your home, there would be a rapid and uneven refrigerant cycle, which causes several problems, including short cycling. Cooling rapidly may sound like a benefit, but the uneven cooling can make your AC turn again sooner than it ought to. Oversized AC can cause short-cycling, leading to other problems such as high power bills, frequent repairs, and a shorter lifespan.
What to do: Have a professional HVAC company use an AC sizing calculator to perform a heat load calculation to ensure your AC is sized correctly. Some HVAC companies can perform whole house evaluations and assessments on airflow and poor installations.
AC Unit Refrigerant Leaks
Refrigerants are coolants that circulate airflow to and from your room. Refrigerant leaks can make your AC system low on refrigerant. There’s a popular misconception that low refrigerant levels occur due to the AC cooling process; however, it actually occurs due to small holes that allow the refrigerant to leak. A low refrigerant level can make the compressor malfunction and go off due to low pressure. When the pressure rises again, the compressor turns back on; this process of turning on and off can make your AC wear and tear faster and cause a system breakdown.
What to do: Refrigerant leaks can cause potential hazards to humans. You should consult a reputable HVAC company to fix the leak.
Faulty compressors usually malfunction and cause overheating: when overheating occurs, it can cause your AC unit to turn off and on frequently. Defective compressors can cause more problems for your AC system and cause the other components to wear and tear faster.
What to do: Contact a local HVAC professional to fix the problem or replace the compressor.
Frozen Evaporator Coil
Some AC problems, such as restricted airflow and refrigerant leaks, can make the evaporator coils freeze. When the evaporator coils are frozen, the AC unit turns off and turns back on when the ice thaws.
What to do: Check if your outdoor unit has ice buildup on it. If it’s frozen, you should get an HVAC professional to diagnose if the air filter or refrigerant leak is causing it and fix it.
Clogged Drain Line
Many AC systems usually come with a “float switch” feature that turns off the AC system when the water in the drain line fails to drain correctly. When you switch your thermostat to “Auto,” and the air still doesn’t circulate, then the drain line could be clogged.
What to do: Contact a local HVAC expert to help you unclog the drain line if you don’t know how to.
Short cycling can also be caused by electrical problems. Sometimes the capacitor or electric supply cable may have faults, or the AC may have electrical faults such can come from the circuits board or even the thermostat; any of these problems can cause the AC unit to turn on and off repeatedly.
What to do: Electrical faults can be difficult to diagnose, and it’s dangerous to diagnose them yourself if you’re not a skilled electrician. You should get a professional electrician to diagnose and fix the problem.