Air Conditioner Turns On [Guide, Problems & Solutions]

Turning an air conditioner on is one of the easiest tasks, and turning it on reduces the temperature in your home. But if the air conditioner turns on or off too often, there may be an internal problem.

air conditioner turns on

Air Conditioner Turns On and Off Right Away – Fixed

If your air conditioner is short cycling, it may indicate an issue with the power supply. The supply may be erratic, which means the air conditioner is in danger of irreparable damage. So, check the power connection to the air conditioner, starting with the circuit breaker and disconnect. Also, check the thermostat and power cord if available. Ensure the thermostat is in good working condition, connected to power, and set to the correct temperature setting. 

The temperature must be about 5 degrees lower than the room temperature, the operating mode must be Cool, and the fan speed must fit the operating mode. Irregular settings can affect how the air conditioner runs and may cause it to turn on and off too often. Reset the breaker and see if the power supply stabilizes. Otherwise, check the power cord where it applies to see if it is damaged. Replace the cord if damaged.

However, if the power supply is not the source of the short cycling problem, and in most cases, it is not, check the following:

1. Condensing Unit

The condenser houses the compressor, condenser coil, and fan. It also holds the capacitor and a few other components. The coil transfers heat from the air conditioning system after the refrigerant absorbs it from the room air. That way, the unit can efficiently run and produce cold air without the problem of overheating. However, if the condenser is significantly dirty, it cannot dissipate heat from the system. 

This affects other parts, including the compressor, and may cause the air conditioner to have issues with functionality. You should clean the condenser once or twice a year to prevent dirt from insulating the coil and building heat. You can use the service of a professional technician to clean it, but you can also use a coil cleaning brush or blower to remove dirt from the outdoor unit.

2. Air Filter

The filter plays a significant role in how the air conditioner functions. It purifies the air and ensures there are no pollutants or contaminants. But when the filter becomes dirty, which happens over a few weeks of constant usage, it creates other problems in the air conditioner. It restricts the airflow in the unit, compromising the cooling and operating capacity. The air conditioner may turn on and off too often as it tries to protect itself from damage resulting from overheating. 

Typically, you should clean the filter every two weeks unless you do not use the unit too often or live in an area with clean air. But if you use it constantly, replace the filter every three months. Ensure you use the correct type for your air conditioner model and check the MERV rating for better air purification. Otherwise, the dirt from the filter can affect the evaporator and blower, which, in turn, reduces the condenser’s functionality and may eventually shut the unit down permanently.

3. Air Conditioner Size

If you have an oversized air conditioner in your home, it will quickly reach the set temperature on the thermostat. And when it does that, it shuts off until the room temperature rises before turning on to run a brief cycle. 

Each air conditioner has British Thermal Units (BTU) rating that allows a user to determine its size and know what fits the size of a room. It is crucial to buy an air conditioning system following the room’s measurement where it will fit before deciding the size. Otherwise, you may have a short cycling problem.

4. Gas Leak

Another possible problem is a refrigerant leak. Low refrigerant levels can cause the air conditioner to have operating issues as there will not be enough to keep it working optimally. You may find the evaporator coil freezing because of a drop in heat absorption, which usually helps to keep it from freezing. 

And the unit will turn on and off as it tries to continue normal operations without much success. A trained HVAC technician should always handle a refrigerant leak. So, if you suspect this issue with your air conditioner, turn it off and call for professional assistance.

Air Conditioner Turns On By Itself – Solved

Several faults can cause an air conditioner to turn on by itself, and one of them is an unstable electrical circuit. But before checking any complex component or area, check to see if the sleep or energy saver mode is active. One or both of these modes can cause the air conditioner to turn itself on at different times, depending on the setting. 

Check the user manual for the air conditioner to determine if this is the case, or check the remote control or thermostat in case you accidentally turn on the setting. A faulty circuit can turn the unit on even when it is not necessary. Faulty wirings can affect the circuit and trigger it to power the unit when it should be off. You must regularly service the air conditioner to prevent such a fault.

While it is rare to see the electrical circuit fail or cause this problem, it happens, especially when there are power supply issues. It may also affect the control board, affecting other components such as the condenser fan, compressor, or internal parts.

Another possible fault is a dirty compressor or condensing unit. As the compressor runs, it builds heat that needs to be dissipated to prevent a buildup. But the location of the compressor in the outdoor unit usually means it eventually gets dirty. 

Dirt insulates it and prevents the efficient dissipation of heat, and over time, the temperature rises to a point where the pressure also rises. Consequently, it interferes with the electrical circuit and shuts down the air conditioner. After a little while, the compressor’s temperature and pressure drop, causing it to turn on the air conditioner. This cycle keeps repeating itself until you clean the condensing unit. 

You may want to hire a technician to check and clean this unit to avoid damaging the condenser fins or getting a high electrical jolt from the wires or capacitor. While the unit is easy to clean, it may be the best step to allow a trained hand to do the job in case something else is causing the problem apart from dirt and heat.

It is also crucial to clean or replace the air filter if it is dirty. Typically, it should be cleaned every two weeks and replaced every two to three months. However, most homeowners do not carry out this service, affecting how the air conditioner functions over time. Dirt from the filter can cause the evaporator coil to freeze due to an airflow restriction. And if the coil freezes, the air conditioner stops functioning as it should. It will turn itself on frequently as it tries to produce cool air unsuccessfully.

There may be a defective safety switch tripping the system. Loose wiring in the switch can cause it to turn off the air conditioner, but the compressor turns it on soon after to resume cooling. So, you may find the unit turning on, off, and on again within seconds. Regular servicing should eliminate this problem, but if it is already there, have a technician troubleshoot further and fix it.

Air Conditioner Turns On and Off By Itself – How to Fix

Sometimes, your air conditioner may turn on, run for a while, and turn off by itself. It may not turn off soon after you turn it on, but if the unit suddenly turns itself off, there is a problem.

1. Thermostat

The first place to check is the thermostat. The thermostat controls the system’s functions and ensures it runs according to the set temperature. If there is a functional issue with the system, it may mean the thermostat is malfunctioning. However, before deciding on the working order of the component, check its location.

Positioning the thermostat too close to the supply vents may cause it to wrongly detect the room temperature and turn the unit on and off by itself. Also, putting it in the path of direct sunlight may cause it to read the room as being too hot. As a result, it triggers the air conditioner to turn on when it is not necessary. 

If any of these applies, or you have the thermostat in another area where the temperature triggers it, you may have to relocate it. But if the location is not the problem, there may be a power issue. If the thermostat uses batteries, replace them and see if it fixes the problem. Otherwise, get a professional to test the thermostat.

2. Condenser

The condenser tends to get dirty if there is no regular maintenance over years of usage. And if the condenser gets dirty, it traps the heat in the system and leads to the unit turning off and on too often. It is crucial to service the air conditioner at least twice a year and ensure the condenser is clean. Do the same for the compressor and other parts in the system.

3. Filter

The filter allows air into the air conditioner after purifying them. The filtration process means that the filter eventually gets significantly dirty, especially if you regularly use the air conditioner. The dirt keeps the air from circulating and leads to short cycling. Clean the filter or replace it if it has been in use too long. Some filters are the disposable type, while others are reusable. However, if the filter gets dirty quickly, you must replace it every three months or less.

4. Drain Line

When the drain line gets clogged, the water stands in the drain pan, and some may go back into the air conditioner. If this happens, there is a float switch that turns off the air conditioner as a way to protect it from damage. Clearing the drain line should cause the water to drain and keep the air conditioner running. You can hire a professional to clean the drain line and keep the air conditioner from short cycling.

5. Evaporator Coil

A frozen evaporator coil can restrict the flow of air. The refrigerant flows into the coil and absorbs the heat in the room air from there. Then, the air flows out into the room. But if the coil is frozen, the air is restricted, heat builds, and the air conditioner starts turning on and off by itself. Dirty filters and low refrigerant levels can lead to a frozen coil, and while you should turn off the unit to allow the coil to thaw, it is only a temporary solution. You should have a technician check the unit to determine whether it is a refrigerant leak or dirty filters.

Note: If the air conditioner is leaking refrigerant, turn it off and call for professional assistance. You should not try to fix the issue yourself as it may be dangerous to your health. Moreover, you may not have the training to detect the leak areas and fix them, so it is best left to an HVAC technician.

6. Compressor

An air conditioner compressor may malfunction, although it rarely happens. Compressors are designed to last up to 15 years, but a few factors can lead to premature damage. And if the compressor malfunctions, it may work extra hard and overheat, causing the air conditioner to turn on and off. 

Since it is the heart of the system, fixing or replacing the compressor is crucial. You must check the cost-effectiveness of replacing a compressor or the entire air conditioning system before deciding on the best step. Let a technician test the compressor and recommend what to do.

There may be electrical issues, such as a defective capacitor or a faulty electrical circuit board. The power supply cable may also be overloaded or damaged. It is dangerous to try to troubleshoot electrical faults yourself; let a professional do the job.

Note: Troubleshoot your RV air conditioner that turns on and off repeatedly by following the steps in this section. If you have additional issues with the unit, turn it off and call for professional assistance.

Air Conditioner Turns On and Off in Car – What to Do

The following are possible reasons your car air conditioner keeps turning on and off:

  • Defective relay
  • Broken fan belt
  • Blown fuse
  • Dirty condensing unit
  • Obstructed intake vent
  • Faulty cooling fan
  • Damaged blower motor
  • Refrigerant issues

1. Relay

A defective relay can cause the air conditioner to turn on and off. The relay is the component that controls the motor functions within the air conditioning system. Moisture or an overload can affect how well the relay works. Take the car to an auto mechanic to check the relay and replace it if necessary.

2. Fan Belt

The belt may be broken, and the air conditioner fan can stop running if it is. Since the fan prevents overheating, the condenser can overheat and cause the unit to short cycle. Therefore, check the fan belt and replace it if broken. Let a technician fix this fault is best unless you have the training to fix it yourself.

There is also the possibility that some air conditioner hoses are damaged. These hoses may tear if the pressure in the system is too high. Too much pressure happens if the refrigerant is too low, and your car needs immediate servicing if the refrigerant is leaking.

3. Fuse

The air conditioner in your car uses fuses to function; if there is a damaged fuse, the system may not function. It is a common reason the air conditioner may turn on and off as you try to use it. Your auto mechanic should be in the best position to check the car and determine whether or not the fuse is damaged and replace it if it is.

4. Condensing Unit

The condenser comprises the fan, condenser coil, compressor, and other components. Typically, it runs while the indoor unit operates to help reduce heat in the system. Without this outdoor unit, the entire air conditioning system does not work. So, if the condensing unit is dirty or faulty, the air conditioner begins to short cycle. Troubleshoot the condenser parts to see if there is a faulty one, especially the compressor and fan. Replace the parts that do not function well.

5. Air Intake Vent

The intake vent allows cool air to flow over the system and lowers the risk of heat buildup. For this reason, it should always be open, and if you close it, whether fully or partially, the system may overheat and short cycle. Ensure the car’s intake vent is fully open, especially when the weather is noticeably hot. However, dirt and debris can block the vent, which requires cleaning, which you can do yourself. Otherwise, have a professional do the job.

6. Cooling Fan

Your car’s air conditioning system has two cooling fans that keep it cool. If one or both fans stop working, the system will overheat and turn on and off. The fan motors may have electrical issues, or dirt may clog them. There is also the possibility that moisture has damaged the motors. Whatever the case, the fans need to be serviced to keep the air conditioner in good working condition.

7. Blower Motor

The blower is the fan inside the indoor unit and circulates the cold air produced by the refrigerant and evaporator coil. It runs when the air conditioner is on, and the fan speed is set. So, if the fan stops working, the air conditioner cannot produce cool air. That means the system overheats and begins to malfunction. The likeliest cause of a failed blower is a defective motor. Therefore, replace the motor and see if the fan starts working.

8. Refrigerant

Two issues can occur with the refrigerant in your car’s air conditioner. One is the more common problem of a refrigerant leak. While it is not always an issue to tackle with an air conditioner, it is easier to understand because more people have to deal with it. However, there is the possibility of having an issue with too much refrigerant in the system. 

Since it runs through a closed system, the refrigerant cannot dissipate unless you manually fix it. This problem usually occurs when you recharge the system and add too much refrigerant. Whether there is a leak or too much refrigerant in the system, let a technician inspect the system and fix any refrigerant issue.

How Long to Allow an Air Conditioner to Sit Before Turning It On?

If the air conditioner is a new installation, you must allow it to sit for about thirty minutes before turning it on for the first time. You may damage certain parts if you turn it on too soon. Some models may require several hours to settle before working properly. Therefore, it is best to consult the user manual for instructions on operating your specific model. 

The primary reason you have to wait before turning it on is that moving it from one place to another usually causes fluids to flow out of their places. So, the air conditioner needs to sit without disturbance for the fluids to flow back to their respective compartments before the unit can work. One tip is leaving the air conditioner and arranging your house before calling an installation team. That gives it enough time to settle.

If you recently moved to a new place and need to install the air conditioner from your old house, you must allow it to sit for about 24 hours to settle. The time is directly dependent on the distance and how rough the journey was. There is also the unit placement during transportation; placing it face down may cause irreparable damages, even if you allow it to sit undisturbed for the recommended period.

Furthermore, consider the age of the air conditioner. Older units need more careful handling than newer ones because of fragility caused by age. If you are moving the unit a long distance, you may want to wrap it with thick clothes for protection. Also, ensure you place it upright so that the oil in the compressor does not flow into the cooling lines and damage the entire system. There are moving instructions for the air conditioner in the manual that you should follow.

How to Turn On Outside Air Conditioner

There is usually a disconnect next to the outdoor condensing unit. The disconnect controls the power flow to the condenser and compressor. It looks like a breaker but specifically for the condenser. If the disconnect is off, the unit will not run. Check the box and see if it is off; turn it on and wait for the condenser to run.

If that does not solve the problem, consider resetting the outdoor unit. Some units have dedicated reset switches visible on the condenser. You may consult the user manual to determine whether or not your specific air conditioner model has such a switch. If it does, press the switch as detailed in the manual to reset the condenser. But if there is no switch, disconnect the unit from electric power for one minute and reconnect it to electric power. Wait to see if the outdoor unit comes on while the indoor unit cools the room.

The circuit breaker must also be working to power the outside unit. If you have trouble turning it on even when you use a switch or the indoor unit is running, there may a wiring problem. The wires may be aging and loose, or there is a blown fuse. Check the fuse box and replace any blown fuses. Otherwise, reset the breaker and see if the unit runs. If it trips shortly after, get an electrician to examine the connections and fix all issues.

Air Conditioner Turns On When Thermostat Is Off – Quick Fix

The most probable reason your air conditioner keeps turning on after you turn off the thermostat is that the thermostat is faulty. Check for shorts in the wiring or disconnections. There may be a corrosion problem, or the thermostat is simply old. It may also stem from the settings, which turn on the unit whether or not the thermostat is running. So, try adjusting the settings and removing timers or any modes to see if the issue continues. If it does, you may have to replace the thermostat or have the old one serviced.

But if the thermostat is in good working condition, check the limit control switch. The thermostat may not be in automatic mode but manual, which means it does not control how the air conditioner functions. Consequently, the unit can turn on and off without the thermostat. Therefore, ensure the limit control switch is on automatic so that the settings on the thermostat can control the air conditioner. It is a straightforward solution, but you may want to use professional assistance if you are unsure what to do.

There is also the possibility that the outside weather is too hot. The air conditioner may cool the room to the setting on the thermostat and shut off. But the extreme heat may trigger it to turn on again without waiting for the thermostat, especially if the room’s temperature warms faster than usual. Leaving the blinds open or having a crack through which warm air enters the room aids this process. You may want to adjust the temperature setting on the thermostat to a slightly lower point to accommodate the hot weather.

Note: If you want to turn on your air conditioner without a remote, use the thermostat. It works as a control panel for the unit, and you can control various functions from there, including powering the unit on or off.

What to Do Before Turning On an Air Conditioner After Winter

Before turning on the air conditioner after winter, the first thing to do is to bring it out of storage. If you had to remove and store it, remove it from storage and check whether or not it is intact. This step does not apply if you did not have to unmount the unit or carry it into storage. The second step is to have an HVAC technician perform a service check on it. Servicing it should catch minor issues and errors and improves the system’s efficiency.

Next, remember to remove any covering on the outdoor condensing unit. It is easy to forget to do so, and running the air conditioner while it is covered may be extremely dangerous. The compressor and condenser may overheat to the point of combustion, but that is only if the covering stays on for too long. 

A service technician should also clean the outdoor unit after uncovering it because it may have gathered some dust in storage. Knowing how to clean it yourself saves you money, but you must tread carefully to avoid damaging the condenser fins or fan blade. Clear out debris in and around the unit, and weed the area if applicable. Check the air filter in the indoor unit and replace it if it is not new. You may have to replace it because it has been sitting idle for months.

Ensure all the air conditioner vents are fully open. If you use a central unit, check the vents around the house to ensure they are open. Closed vents lead to restricted airflow and eventual overheating, which is detrimental to the air conditioner in the long run.

Air Conditioner Smells Bad When Turned On in Car – Solved

A smelly car air conditioner may result from long-term mildew or mold growth. This article on a car air conditioner smelling when turned on explains that humidity can encourage mold growth and that using the coldest temperature always helps condensation to build in the unit. Follow the instructions in the article to fix the smell coming from the air conditioner and take careful steps to prevent a future occurrence.

Why Won’t Air Conditioner Turn On?

The power switch may be faulty, or the thermostat may have failed. These two factors are the primary reason for an air conditioner not turning on, even if you manually activate it. Other possible causes are a faulty outdoor condensing unit, clogged air filter, capacitor failure, a lack of regular usage, low refrigerant levels, and age. Follow the instructions in this guide to fix the problem and get the air conditioning working again.

Leave a Comment