Air Conditioner Not Turning Off [Proven Solutions]

It is one thing to have an air conditioner not turning on, but it is entirely different if you have an air conditioner not turning off. What do you do? This article helps you fix the problem.

air conditioner not turning off

Air Conditioner Not Turning Off – How to Fix

Several issues can cause an air conditioner to run all the time. If you notice your system does not turn off, even when it should automatically cycle off, you may have issues with the following parts:

1. Thermostat

Setting the thermostat wrong can keep the air conditioner running constantly. Check to see if you accidentally set it to Fan mode; that may explain why it is always running. It means the fan operates all the time instead of only when the cooling mode is active. You may want to adjust the setting to cool the room by setting it to Cool mode of operation or turn off the air conditioner from the power outlet. Also, ensure the thermostat is set to Auto, not On, as this setting may keep the system running.

Another possibility is that the temperature setting is lower than usual. As a result, the air conditioner constantly runs to reach the set temperature and never seems to go off. This may happen in a place where more than one person has access to the thermostat and constantly adjusts the set temperature. You may want to keep it at a steady temperature, a few degrees lower than the room temperature. That way, the air conditioner can run and cycle off when appropriate.

But if the temperature or mode setting is not the problem, the thermostat may be faulty. This is typically true when the thermostat is older than ten years. In such a case, you may have to replace the component but change the batteries and see if there is an improvement in how it functions. If none, replace the thermostat or have a technician calibrate it.

Note: This solution applies if you have trouble with an air conditioner not turning off from the thermostat.

2. Air Filter

You may wonder what the filter has to do with whether or not an air conditioner turns off. The air filter plays a significant role in how well an air conditioner functions because it purifies the air before it enters the system. Over time, dirt and other air contaminants clog the filter and slow its operation. Not only does it become unable to filter the air, but it also may add pollutants to the air. Additionally, the dirty filter restricts the airflow, which causes the air conditioner to run all the time as it tries to maintain a cool temperature in the house.

Therefore, check the air filter, especially if the thermostat is in good working condition. Remove and clean it if the filter is still usable. However, it is always best to replace it every two months to keep the air conditioner in good working condition. Ensure you use the correct filter type for your air conditioner brand and type, and check the MERV rating; the higher the MERV, the better it purifies the air.

3. Condenser

The condenser comprises the coil, fan, and other electrical connections. You will also find the compressor in the outdoor condensing unit. Typically, the condenser coil removes heat from the system and condenses the refrigerant during the cooling cycle. But if the coil becomes clogged with debris due to its location outside the house, it cannot remove the heat. 

Consequently, it builds heat within the system and restricts airflow, which affects how the air conditioner works. The air conditioner will work harder than usual to keep the air cold if the condenser is significantly dirty. The reason is that dirt acts as insulation that traps heat in the system. 

So, clean the condenser fins and fan, ensuring no dirt is trapped in it. The fan must also be in good working order to help release the heat into the atmosphere and keep the system from overheating. You may need a professional technician for the cleaning job because the condenser fins are fragile, and it may be difficult to clean them well.

4. Evaporator Coil

Another part ot check is the evaporator coil. The coil is usually in the indoor unit, where it holds the refrigerant as it absorbs the heat in the air. If the air conditioner seems to run constantly without producing much cool air, check the coil for signs of freezing. It should be cold but not to the point of freezing. 

And if it is frozen, it means there is a buildup of dirt, a clogged condensate drain and pan, or poor airflow, all of which may point to a dirty air filter. There is also the possibility that the system has a low refrigerant level. Therefore, clean or replace the filter. Also, clean the coil yourself with a no-rinse coil cleaner or have an HVAC technician do it for a more professional finish. 

Remove the drain pan, clean it, and clear the drain pipe using a wet/dry vacuum, which you can rent if you do not have one. Alternatively, use a water and bleach solution to clean and sanitize the pipe. Regular maintenance should keep the evaporator coil from freezing. It is crucial to care for the coil because it may eventually damage the air conditioning system if it keeps clogging due to dirt or poor airflow.

5. Fan Switch

The fan switch controls how the fan’s motor runs. When you set the fan to the correct setting, the switch ensures it runs according to the cooling cycles. However, if the fan constantly runs, even when the air conditioner does not cycle, it may mean that the switch is stuck in override. You may find the switch next to the blower’s motor; reset it following the instructions in the user manual. It should correct the error and get the fan to work according to the thermostat’s setting. Otherwise, your air conditioner may require servicing.

6. Electrical Connections

The relay switch or capacitor may be defective, affecting how the air conditioner works. The compressor’s contactor may also malfunction, fusing into a closed position. Additionally, there may be loose or damaged wires in the system. Unfortunately, you may not be able to check and fix these issues; only a certified HVAC technician should do it due to the presence of electricity.  They should also run an entire system check to ensure no other electric part malfunctions.

7. Air Conditioner Size

An undersized air conditioning system will have a harder time cooling a house than a system of the correct size. If the system is too small, it explains why it constantly runs. It needs more hours to produce cool air for the house, and it will always cycle on if its sensor detects pockets of warm air in the space. Air conditioners work by size and capacity based on the size of the room, so you may have to exchange the unit for an appropriately-sized one or buy an entirely new system.

8. Refrigerant

The last possibility is that the sealed system is compromised, and the refrigerant leaks. It is not an uncommon problem to see an air conditioner leaking refrigerant, especially in these days of harsh cleaning agents and corrosive rainwater. However, it is not so common that it should be the first thing you check. 

Therefore, if nothing else seems to cause the problem of an air conditioner constantly running, it may indicate the loss of refrigerant. As a result, the system cannot produce enough cold air and has to work harder to maintain a cold temperature. Ice on the evaporator coil is a tell-tale sign that the system has low refrigerant levels, especially if the filter is clean. 

So, turn off the air conditioner from the breaker, contact the air conditioner’s manufacturing brand to report the issue, and request service. Alternatively, hire an independent HVAC technician for further assistance. Always professional help to fix a refrigerant leak and create proper ventilation to avoid refrigerant poisoning, which may happen if you inhale large amounts.

Important Notes

The same troubleshooting and repair steps apply if you have a problem with your RV air conditioner not turning off. Also, note that the air conditioner may not turn off if the weather is hot. You may find it constantly running as it tries to combat the extreme outside weather. Consequently, it will cycle on too often or stay running without cycling off. Lowering the set temperature a few degrees may help, but ensure you adjust it to appropriate settings when the weather eases to keep the air conditioner functioning optimally.

Also, the compressor may be nearing the end of its lifespan. If the air conditioner is old, the problem may be due to the compressor being too old and worn out. One of the signs of an old and tired compressor is noise and constant operation. Other times, it may not work at all. If you are unsure, get a technician to test the compressor and check if the problem is from the motor. And if it is, you may have to replace the compressor, depending on the cost of buying a new air conditioner.

Air Conditioning Not Turning Off in Car – Solved

Check the following if the air conditioner in your car does not turn off:

1. Automatic Climate Control

Newer model cars have a feature that checks and controls their interior temperature. The feature ensures the car is not too hot or too cold. But if the car’s air conditioner is on, the climate control must be off. Otherwise, it interferes with the interior temperature and causes the compressor to run constantly due to temperature fluctuations.

Simply put, the automatic climate control switch must be off if the air conditioner must turn off. The sensor may read the car’s interior temperature as too hot and keep the air conditioner running longer than normal. You may want a technician to check and ensure the climate control works well.

2. Air Filter

As explained, the filter is vital to how an air conditioner functions. A significantly dirty filter restricts airflow and forces the air conditioner to run constantly to keep the produce enough cool air. This issue may also affect other parts of the cooling system and may eventually stop the air conditioner from working. Checking and replacing the filter is crucial for the system’s function. Therefore, clean the filter or replace it yourself. Alternatively, take the car to an auto technician to change the filter and check for other faults.

3. Condenser

The condenser in any air conditioning system is vital to its functionality. The condenser comprises the compressor, condenser fan, and fins that condense the refrigerant and release the excess heat from the system into the atmosphere. Proper air circulation in the condenser is crucial to prevent overheating, which may keep the air conditioner running longer than usual.

So, if your car’s system runs more than it should, check the condenser for dirt. A significant amount of dirt on the condenser fins traps the heat in the system and eventually leads to overheating. This part of the air conditioning system must be cleaned once or twice every year for optimum performance. Therefore, take your car to your auto mechanic and have them clean the coil. Doing that should help the air conditioner turn off and regulate how it functions.

4. Evaporator

Another vital part of the cooling system in an air conditioner is the evaporator coil. Its most important job is to hold the refrigerant as it absorbs the heat from the room air. It functions in a way that any obstruction may cause it to freeze. 

Over time, dirt from a leaking duct or dirty air filter may clog the coil and cause it to freeze. Also, low refrigerant levels can reduce the pressure and cause the evaporator coil to freeze. And if it freezes, the air conditioner will not have enough air, which causes it to run constantly. 

Therefore, have a service technician check the evaporator for possible frosting and thaw it if applicable you must also replace the filter if not already done and check the pipes for possible leakage.

5. Refrigerant

If all else fails, you may have a leaking closed system. Typically, an air conditioner, whether in a car or house, should not deplete because it runs through a closed loop. But if there is a sudden drop in the refrigerant level, the system has developed a leak, probably through a tiny puncture. Only a qualified technician should test and fix a refrigerant leak because of the danger. These leaks do not always happen, but if your car is leaking gas, you must not use the air conditioner until you fix it.

Air Conditioner Fan Not Turning Off – What to Do

If the fan in your air conditioner constantly runs, there may be a problem with the unit’s size. Air conditioners installed in houses or spaces too big for them run all the time to maintain a cool temperature. That means the fan and compressor may run simultaneously so that the condenser does not overheat. 

Another possible problem is the temperature and mode settings. Incorrect settings determine how the system functions. Also, the fan may be incorrectly set; it should be on Auto instead of On. Otherwise, it will constantly run. In addition, check the thermostat and relay switch; one or both components may be defective. This article on an air conditioner fan always running explains steps to troubleshoot and fix the fan problem.

Air Conditioner Outside Unit Not Turning Off – Fixed

A few faults can keep the outdoor unit of your air conditioning system running, even when you shut it off. The first thing to check is the thermostat since it controls the settings and power functions of the system. A faulty thermostat may be sending the wrong signals to the outdoor unit to keep running when it is not necessary.

So, turn off the outdoor unit from the disconnect next to it and see if the thermostat can control the indoor unit alone. If it cannot, you have your answer; a technician can test the wiring or recommend another solution. You may want to replace the batteries or get a new thermostat in such a case. But if it works, the problem may stem from the wire connection to the outdoor unit.

The thermostat cable may be corroded or worn. Also, rodents may have eaten it over the years, affecting how well the thermostat controls the condensing unit. Disconnect the thermostat cable from the outdoor unit and the thermostat, and run a continuity check on it using a multimeter. There should be no continuity since there is no connection, and if that is the case, inspect the cable for damage. Hire an appliance technician for repairs if the cable requires attention.

You may also want to check the compressor’s contactor. Years of constant use can wear the contactor out and cause it to fuse shut. As a result, the outdoor condensing unit cannot turn off since the compressor will continue to run. Inspect the contactor and replace it if stuck; do this every few years since the contactor tends to fuse shut quickly. This is part of maintaining an air conditioner, so it may be best to employ the services of an HVAC technician to check and replace the contactor and check for other possible faults.

Air Conditioner Compressor Does Not Turn Off – Quick Fix

An air conditioner compressor that does not turn off is a serious problem with the potential to damage the entire system. If you discover that the compressor does not turn off, ensure the air filter is clean or replace it if you have used it for longer than two months. Also, check the thermostat’s temperature setting; low temperatures keep the compressor from shutting off.

The condenser coil may be significantly dirty, which builds heat and compromises the cooling system. Additionally, the compressor’s contact may have welded shut from overuse, or there is insufficient refrigerant. Check out this article on an air conditioner compressor not shutting off for helpful troubleshooting and repair resources.

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