The air conditioner is the common solution for seeking relief in the burning summer. If your AC is not draining water, it must result from certain faults. If you want to know the common causes and fix them, you are at the right place.

If your AC unit is not draining water, check the drain pipe. Inspect if it is clogged. Unclog the drain pipe to fix the issue. Other causes include a frozen evaporator coil, disconnected drain line connection, and condensation pump faults. Inspect these and replace them if needed. 

In this article, you will learn common causes of why your AC drain pipe is not dripping and steps to unclog the clogged drain pipe. So, Keep reading.

What are the signs of a clogged AC drain pipe?

It’s not to deny that a good AC unit can provide relief after a tiring day, especially during summer. 

But the struggle is real when the AC unit poses issues when you need it the most. 

If you have noticed that the drain pipe is not draining water, it may be the cause of the faults in your AC units. 

A clogged drain pipe is the major cause of why the AC unit is not draining water.

Not sure if the clouded drain pipe is the cause of the issue? 

Here we go!

Below listed are the common signs of a clogged AC drain pipe:

• Complete shutdown of the AC unit. 
• Water leakage near the AC unit. 
• No efficient cooling. 
• Bad odor near the AC unit. 
• Your housemates are getting allergies frequently. 
• Reduced airflow in the AC unit. 
• The drain pan is overflowing. 

If you notice any of these signs in your AC units, you can confirm that the drain pipe in your AC unit is clogged.

The potential health hazards caused by a clogged AC drain pipe

A condensate drain pipe of the AC unit runs through the walls and ceilings by being connected to the outdoor installation of the AC unit. 

The cold coils suck the humidity into the house, which is expelled through the drain pipe. 

If the drain pipe is clogged, the excess water will stagnate in the AC unit and reduce airflow. 

Due to the stagnant water, there will be mold and bacterial growth.

In addition, algae start to spread in the long run. 

Due to mold and bacterial growth, serious health problems occur. 

It is well-known that mold usually grows in damp areas.

When the drain pipe is clogged, it becomes a favorable environment for mold growth, and it starts producing the infectious substance which people eventually inhale, causing health hazards like asthma, eye itching, 

And persistent sneezing issues. 

And bacterial growth causes harm to humans by releasing toxins into the air, causing headaches and fatigue. 

People with low immunity can be easily affected by inhaling the infected air. 

Another possible issue occurs due to the invasion of cockroaches and other harmful insects as the environment is favorable for their growth.

It becomes a threat to health when these insects spread allergic particles into the air resulting in health hazards. 

Severe health hazards are common if the clogged drain pipe is not cleaned for a long time.

The impact of clogged drain pipes on energy efficiency

As discussed already, the main role of the drain line is to expel the condensation collected by the evaporator coil.

Because of this, the condition of the AC drain line is important to keep the humidity in your home in control. 

If the drain pipe is clogged, it will reduce energy efficiency. 

It affects the AC unit because the water damage due to the clogged drain pipe will damage its entire functionality. 

You will have to replace the entire unit.

And also, clogged drain pipes will freeze the AC unit.

Water will be retained in the unit, eventually freezing the condenser coil. 

When the condenser coils are frozen, the unit will have low airflow.

It will result in reduced energy efficiency. At times, overheating occurs in the AC unit, and it will shut down. 

If there is moisture in the drain pipe, a clogged drain pipe will freeze the moisture, resulting in the complete shutdown of the AC unit. 

The drain pan in the AC unit will start to overflow and affect the functionality of the AC unit.

Causes of clogged AC drain pipes

There are several causes why drain pipes are clogged.

Here are the common causes mentioned below.

1. Loose drain line connection

If your AC drain line is not draining water, it may be due to the disconnected or loosely connected drain pipe.

The drain line pipe is the medium connected with the interior of the AC unit to the outside of the home to expel excess moisture.

PVC pipes are drain lines that extend up to the outside of your house. 

When you notice your AC is not draining water, check if the drain pipe is loosely connected with the air handler or completely disconnected.

In such a case, tightening the drain pipe with the air handler will solve the issue.

If the drain pipe is tightly secured with the air handler, there will be a smooth flow of water from the AC unit to the end of the pipe.

2. Drain pan corrosion

A drain pan is usually made of metal or plastic, which differs based on brand and model. 

It is located below the evaporator coil to accommodate any excess moisture that results from the condensation process occurring in the process of cooling the house. 

The drain pan may be corroded if you have used the AC unit for the longest time. 

If the drain pan is run, see if you can clean the rust.

Detach the drain pan from the AC unit and clean it thoroughly using sandpaper. 

If you see cracks or damages in the drain pan, you must replace the drain pan. 

Hire a professional to replace the drain pan if you are not familiar with working with the electrical appliance. 

If the drain pan is cracked, the water will start leaking near the AC unit, damaging both the AC unit and the ceilings.

3. Condensate pump issues

The condensate pump is an important part of the AC unit, which pumps the condensed water to prevent it from dripping onto the floor. 

If the condensate pump is faulty, it won’t pump the water to the drain line pipe. 

So, check if the condensate pump is faulty, and replace it to fix the issue. 

4. The evaporator coil became frozen

As already discussed, the evaporator coil is continuously exposed to water.

So, there are more chances of corrosion in the evaporator coil. 

If the evaporator coil is rusty, the condensation water will start leaking, and it will cause damage to the AC unit.

And it also causes damage to the walls and ceilings. 

Frozen evaporator coils became inefficient in bringing the water to the drain pipe. 

The AC unit will not cool the house properly when this issue occurs. 

Due to the excess heat, the people who inhale the air will have more chances of illness. 

Another threatening issue is a short circuit caused when water leakage occurs due to the water leakage. 

It also leads to the complete shutdown of the AC unit.

So, it is important to check the evaporator coil. 

Hire a professional to check and replace it if it is completely damaged. 

5. Dirty evaporator coil

There are more chances of the evaporator coil getting trapped with dirt and debris particles.

If the evaporator coil is dumped with dirt, the water will not flow to the drain pipe.

As the water is stuck stagnant, there will be a leakage in the AC unit.

To fix this issue, you must clean the evaporator coils regularly.

6. Poor maintenance

It is important to clean the evaporator coil and the drain pipe regularly.

If you don’t clean it often, the dirt and debris will accumulate and cause a clog in the drain pipe. 

If the drain pipe is clogged, the AC unit will cause issues.

In the later part, let’s discuss maintaining the AC unit. 

These are the common reasons for the AC unit not draining.

DIY methods for unclogging AC drain pipes (Fix)

Follow the steps to unclog the AC drain pipe in your AC units. 

1. Gather all the tools

Before starting the cleaning, gather all the necessary tools.

When you gather all the tools, it will be easy to do the cleaning without hassle. 

These are the list of tools you need to unclog the AC drains.

• Wet dry vacuum
• Duct tape
• Garden house
• Water
• AC drain line wire
• Vinegar

Gather all these and start the cleaning process to unclog the drain pipe. 

2. Turn off the AC

Begin by disconnecting the power supply to the AC unit by turning off the circuit breaker.

It is important to ensure safety, as unclogging the drain pipe with the power supply connected will cause electric hazards. 

Access the circuit breaker supplying the power to the AC unit and turn it off.

3. Access the front panel

The front panel is the outer cover of the AC unit.

Locate the screws at the top, bottom, and side of the AC unit. 

Using a screwdriver, unthread the screws to detach the front panel. 

The location of the screws in the front panel will differ based on the brand and the model of the AC unit. 

You can access the internal parts of the AC unit by removing the front panel.

4. Check the drain pan

When the clog occurs in the drain pipe, you can see a drain pan filled with water, and overflowing is also common. 

You have to clean all the water using a towel and sponge.

Remove the water completely and check for any dirt and debris accumulation. 

Prepare a vinegar-cleaning solution or soap solution to remove the dirt. 

Pour the cleaning solution into the drain pan and clean the drain pan completely.

Cleaning with vinegar will help keep the drain pan and eliminate mold and algae growth.

5. Clean the drain hole

Near the drain pan, you can find the drain hole.

Inspect if there is dirt and debris accumulated in the space. 

Insert the drain line wire into the hole to remove all the dirt and debris particles. 

If you don’t have the drain wire, wear gloves on your hands and clean it manually.

6. Inspect the drain pipe

You can see a drain pipe near the drain hole.

One side of the drain pipe is attached to the condensate pan, and the other is attached to the exterior wall of the unit. 

Inspect if there are clogs in the drain pipe.

Unclog them if they are blocking the smooth water flow.

7. Remove the clogs in the drain line

Follow the steps below to unclog the drain pipe:

• Use a vacuum and seal it with the help of duct tape. Plug in the vacuum and remove all the dirt and debris from the drain pipe.
• Insert the drain line wire into the drain pipe and turn it around it. Doing this will break the clog. It would be best if you did not push the wire in the direction of the air handler, as it may damage the AC unit.
• Next, you can use a garden hose to water the pipe. Water pressure from the hose will unclog most of the dirt and debris.
• Now, prepare the vinegar solution to clean the drain line. Run the vinegar solution in the drain pipe and let it soak for 30 minutes. It will help to remove the stubborn dirt accumulation. 

8. Clean the drain line with water

After cleaning the drain pipe with vinegar, run the water throughout the drain pipe to remove the vinegar residue. 

You can confirm that the drain pipe is unclogged if the water flows freely.

9. Reassemble your AC unit

After unclogging the drain pipe, reattach the front panel to the AC unit and close the vent with the cap. 

If you can’t unclog the drain pipe, consider hiring a professional to do the job.

How do I maintain an AC unit to prevent clogged drain pipes?

When you maintain the AC unit properly, you can prevent clogs in the drain pipes.

Here are a few tips on maintaining the AC unit to prevent clogs in the drain pipe:

• Clean the air conditioner’s air filters regularly. It accumulates lots of dirt and dirt while doing the filtering process. It would be best if you cleaned it regularly to prevent clogs.
• Run clean water through the drain pipes regularly. Flushing the water often will remove dirt and debris and prevent clogs.
• Consider installing a condensate trap to prevent the accumulation of dirt and debris. 

The difference between a clogged AC drain pipe and a malfunctioning AC unit

A clogged AC drain pipe will cause leakage issues and reduce airflow, resulting in the overheating of the AC unit.

At times, it completely shuts down. In contrast, the malfunctioning AC unit will produce unusual noises, warm air, and high electricity bills.

Final words

If your AC is not draining water, it will completely shut down the system. So, it is important to fix the issue immediately. Check the drain pipe is clogged. Unclog the pipe with the vinegar solution to remove the stubborn dirt and debris accumulation. 

Clean the air filter regularly to prevent dust and debris accumulation. Follow the steps mentioned in the article to unclog the drain pipe. 

Check the interior components of the AC units, like the evaporator coil, pump, and drain pan. If any of these are defective, replace them to resolve the problem.

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Air conditioners are meant to cool down your house and comfort you, mostly during the summers. Generally, your air conditioning unit won’t need anything from you except for the thermostat adjustment. However, it is concerning if it makes loud noise during operation. 

An AC makes loud noises due to loose or broken parts, faulty capacitors, clogging due to outdoor debris, or a refrigerant leak. Tighten the screws, clean the coils, remove debris, and fix the refrigerant tank. Consider soundproofing for the inside and outside units to reduce the noise. 

There are many other reasons behind a noisy AC, and we have outlined them all in this guide. Since there are numerous reasons, you must confirm the real cause and troubleshoot it. If confused, hire a professional to deal with it. 

What types of noise does an air conditioner make?

When something is wrong with your air conditioner, it has symptoms, for example, leakage, not working, insufficient cold air, loud noises, etc. 

In terms of noise, the air conditioner makes different types of alarming and loud noises, for example:

• Humming 
• Buzzing
• Screeching or squealing
• Clicking or tapping
• Rattling or clanking
• Whistling
• Crackling
• Banging
• Hissing
• Whistling

Different noises will mean different types of problems. Sometimes, one noise type could mean different problems. 

So you must identify the noise type and detect the right problem behind a noisy air conditioning unit. 

Why does my air conditioner make loud noises?

There are many reasons behind a noisy air conditioner. Some of them include the following:

• Loose or broken parts
• Failed thermostat or defective control
• Loose fan spades
• Clogging
• Refrigerant leaks

Let’s get to the reasons behind the noise and how to solve it. 

1. Dirt particles are stuck inside the condenser.

Your air conditioner will have a banging or rattling noise due to dirt particles accumulated inside the condenser. 

The condenser will collect sticks, leaves, and other direct particles inside, especially if the outdoor unit is close to the trees and shrubs. 

The small leaves and twigs will get stuck inside the condenser, and you will probably forget to remove them.

The dirt and debris block the condenser from releasing the hot air out of your house. 

Handling the outdoor unit is easier than the indoor one. 

Remove the condenser cover to throw away the stuck materials.

Ensure your outdoor unit is at least 2 to 3 feet away from the trees and shrubs. 

2. Loose wires

Your air conditioner will make a loud buzzing noise if there are any loose or exposed wires in your unit.

You must turn off your unit to avoid electric sparks and call for the experts to fix the wires. 

3. Loose screws and components

A rattling sound indicates a problem – loose screws in your air conditioner. 

Both indoor and outdoor units can have loose screws and make loud rattling noises whenever you turn them on the unit. 

Sometimes, you will also hear buzzing noises if any parts inside the air conditioner are loose. 

Over time, the vibration will increase along with the noise. 

Check your units carefully and tighten the screws and other parts with a screwdriver. 

4. Broken fan motor or compressor

If your air conditioner makes a loud banging noise, it could be due to the broken motors or compressors or an imbalance fan. 

You can bend the fan blades of an imbalance fan and bring them to an even position. Make sure to be gentle about it.

Replacing a compressor or a motor can be very costly. 

So, if your air conditioner is quite old, give up the unit instead of replacing the compressor. 

5. Faulty fan motor and bearings

When you turn on the air conditioner, you will hear a screeching or squealing noise, like metal-on-metal. 

It is probably due to faulty fan motor bearings. 

Replace the motor bearings to avoid noise. 

A faulty motor causes a loud buzzing noise, especially when the copper lines connected to the AC face obstruction or the lines are rubbing against each other. 

You must keep the lines well-insulated and reduce the metal-on-metal contact.

6. A worn-out or broken belt

An old or broken fan belt will also create a squealing noise from your air conditioner, especially in ducted or central units. 

In the older models, a belt connects the motor to the fan. 

This belt can wear out over time and create annoying noises. 

High humidity levels are also considered the culprit behind the constant contraction and expansion of the belt in summer, creating an unpleasant noise. 

You must contact the HVAC expert team to replace or repair the belt.

7. High pressure in the compressor unit

Another reason behind a hissing noise transferring to a high-pitched squealing noise is excessive pressure in the compressor unit. 

Please turn off the air conditioner whenever you hear the noise because it can cause an explosion. 

Please call an HVAC professional team to help you here. 

8. Loose fan blade or coil

Fan blades or coils become loose over time. 

As a result, your air conditioner will release a loud pulsating noise.  

To solve the problem, tighten the screws of the blades and the coils. 

Soon your unit will be back to normal. 

9. Air conditioner plastic base 

If your air conditioner has a plastic base, the compressor’s motion will cause the whole unit to create a pulsating noise. 

To prevent the problem, you need to replace the plastic base or pad with a wooden one. 

It will reduce the vibrations and the noise. 

You can do it yourself by clamping the unit down on the pad and then supporting it over small rubber blocks. 

10. Refrigerant coming in contact with the air conditioner walls

When the refrigerant line touches the walls of the air conditioner, there will be a loud pulsating noise. 

When this happens, check for the contact, move the lines slightly away from the wall, and add insulation with the help of rubber or foam material. 

11. Leaking refrigerant 

Your air conditioner will make a loud hissing noise when it leaks the refrigerant liquid. 

Over time, the tubes get rusted, cracked, or eroded, for which the fluid will start leaking. 

The fluid leakage can cause damage to the refrigerant tank. 

The leakage won’t let your room stay cool.

You must call an HVAC expert to repair, seal, or replace the tank and refill the fluid again. 

If the refrigerant lines are improperly sealed, you will hear a loud bubbling or gurgling noise from your unit. 

These sounds indicate the very problem. 

So you don’t have to waste time guessing it. 

The air gets trapped inside the lines, therefore making a gurgling sound. 

12. Compressor valve leak

The compressor valve leak will make your air conditioner release a hissing sound. 

The valve controls the pressure of the refrigerant. 

So, you must hire an HVAC professional to fix the problem. 

Otherwise, it can lead to severe damage. 

13. An obstacle in the air conditioner fans

Your air conditioner’s outdoor unit will make a clicking sound when there is an obstacle in the fans. 

You need to remove the obstacle from the fan. 

Remove the unit’s cover and wipe out the fans properly.

Maintaining regular maintenance of the unit can prevent the problem. 

14. The capacitor loses the charge.

If the capacitor loses its charge, you will hear a loud clicking sound from your air conditioner. 

When the capacitor loses its charge, it cannot power the compressor anymore. As a result, your air conditioner will release a clicking noise. 

The noise occurs because the outdoor unit is constantly trying to turn on. 

You must hire an expert for a checkup. 

15. Capacitor breakdown

You will hear a loud buzzing noise if the capacitor has gone bad, which is later transferred to a loud grinding noise. 

It is the pistons of the compressor that makes the noise.

A good capacitor will store the energy until the unit needs it. 

Slowly, it releases the energy to power the outside AC unit.

A bad capacitor will prevent the fan from turning on despite the current flow, causing a buzzing sound. 

A trained HVAC technician will help you repair or replace the capacitor after a thorough inspection. 

16. Fault in the electrical signals

Faulty electrical signals make the switches turn on and off constantly, producing clicking noises from the unit. 

If you find small sparks accompanying the clicking noises, shut down your air conditioner and call the local HVAC team for a lookout. 

Sparks can be dangerous. 

17. Loose air conditioner fan

Sometimes the air conditioner’s fan will become loose and hit the outdoor unit. 

As a result, you will often hear a loud clicking noise from the unit. 

You need to call an HVAC expert to look at the AC fan. 

The team will look into the condition and may tighten the fan with a screwdriver, or they will replace the fan. 

18. Malfunctioning thermostat

A malfunctioned thermostat will make your air conditioner make a loud clicking noise. 

Besides, it won’t let your unit work properly. 

When a thermostat works normally, the clicking sound will be very mild and soft. 

The sound is of the relay switch when it sends power to the air conditioner. 

If the relay switch is broken or has wire issues, the switch will send power, but you will hear a loud clicking noise. 

However, it won’t let your unit turn on. 

You need to contact a professional as you cannot fix it yourself. 

19. Leaking AC duct

The leak in your air conditioner’s duct will make loud whistling noises. 

The solution is to seal the leakage in the ductwork. 

Besides the whistling noises, your energy bills will also increase. 

20. Obstruction in the airflow

If the AC’s airflow gets obstructed for some reason, the high pressure in the blower fan motor will have high-pitched whistling noise due to the lack of air. 

The dirty air filters are the main reason behind obstructed airflow. 

The dirt and debris create a thick layer and make the blower motor pull the air into the unit forcefully. 

The air that passes through the cracks forcefully will make noises. 

You must replace or wash the air filters every 3-4 months. 

21. Low lubricant level

When a motor releases a loud humming sound, it indicates that the lubricant level is low. 

If the air conditioner runs without a lubricated motor, the humming sound will change into a loud grinding noise. 

You can do it yourself if you have done it before. Otherwise, call professionals to lubricate the motor.

Lubricating the motors every summer and winter will prevent the noise

22. Contactor failure

The contactor controls the electricity flow to the air conditioning unit.

It is like a bridge that connects the unit to the power supply.

When you turn off the air conditioner, the contactor will open to disable the power. 

When you turn it on, the reverse occurs, and the power supply returns. 

If the contactor fails, the air conditioner will make a humming noise because the unit will receive the power but fail to turn on. 

If the problem persists, the humming noise will progress to a loud buzz.

You can correct the problem with a slight tapping if the contactor is stuck. 

Otherwise, you will need a professional’s help.

23. Bent fin coils

The air conditioner will make a humming noise if the fin coils have bent. 

You can fix the fin coils using a metal comb to straighten the bent coils. 

Maintaining the unit from time to time can prevent the fin coils from bending and keep them in the best shape. 

24. Frozen evaporator

When you set the temperature very low, the moisture fails to drain properly. 

Additionally, the evaporator’s coils will freeze due to dirty fins. 

When you find ice falling from the air conditioner’s coils, it will make a cracking sound.

You need to disassemble the air conditioner to access the fins. 

Wash them with soap water thoroughly and let them dry. 

You should only do it yourself if you have done it before. 

Otherwise, call for a professional’s help.

25. Malfunctioned compressor

If you hear loud buzzing noises from the air conditioner, it is probably due to the malfunctioned compressor. 

If the air conditioner still gets power after the compressor has malfunctioned, you will hear a buzzing noise. 

You need to replace the compressor with the help of a professional. Compressors can be very expensive. 

Before replacing, see if your AC will work well after this. 

If the unit has been very old, you can replace the whole unit and get a new one instead of only buying the compressor. 

26. Frozen AC parts

A loud buzzing sound is heard from the air conditioner if the AC parts are freezing. 

It mostly happens in indoor units due to low refrigerant or low thermostat settings. 

It would be best to hire an HVAC to find out which of these reasons causes the freezing. 

27. Excessive moisture in the unit

Blockage in the condensate lines creates moisture buildup, causing a bubbling sound. 

The line helps remove the moisture collected by the air conditioner. 

If the water cannot release from the line, it will make bubbling or gurgling noises. ‘

The same happens when the condensate pump gets damaged. 

The pump pumps the water from the drain pan to the condensate line to exit your house. 

Excessive moisture buildup in the pump will make bubbling sounds. 

Disassemble your air conditioner to check the drainage line. 

However, you cannot do anything here. Get an expert’s help to fix the problem. 

How to make the air conditioner quiet?

Sometimes, solving the above problems is the only way to reduce noise from your air conditioner. 

But if you consult the HVAC experts and they do not find anything wrong with your air conditioner, you will need to find ways to reduce the noise. 

Soundproofing the unit is one of the best ways to make your air conditioner quiet or less noisy. 

Reducing noise in the outdoor unit

To reduce noise in the outdoor unit, you can do the following three things:

1. Sound blanket

You can install a sound blanket inside the unit. 

A sound blanket does not mean you will be cozying the unit with something fluffy. 

The sound blanket will be installed inside the unit on top of the compressor to stifle the sound. 

2. Sound wall

Create a barrier between the outdoor unit and your house with the help of a fence that can muffle the sound of the air conditioning unit. 

The wall will dampen the unit’s sound and keep dirt and debris from entering. Besides, it also gives your house an appealing look. 

3. Landscaping

You can plant shrubbery surrounding your outdoor AC unit to reduce the noise. 

Ensure the landscape upkeep plant is in place to prevent the leaves, sticks, and twigs from entering the unit. 

Reducing noise in the indoor unit

Follow the following tips to reduce noise from the indoor unit:

1. Unit Placement 

Choosing the right position for your unit can help prevent noise. 

Install it away from living rooms, bedrooms, or patio areas. 

Also, ensure that the room does not reflect the noise of your AC, for example, brick walls. 

Areas with reflective surfaces increase the noise greatly. 

2. Insulation 

Add a mat to absorb the vibrations and noises of your unit. 

You can also cover the air ducts with sound-absorbing foam to decrease the noise and prevent it from getting carried inside the house. 

When should I replace the noisy air conditioner?

You need to call an expert for a thorough checkup when your unit makes loud and alarming noises. 

If your unit has become quite old and frequently makes weird noises, you can replace the whole unit instead of just the parts. 

Excessive noise from older units is a sign of deterioration. 

Buying a new air conditioner will be less noisy and energy-efficient. 

To prevent noises, allow regular maintenance. 

The HVAC team can inform you about what is wrong with your unit and what and how quickly you should fix things.

Also Check:

• 12 Reasons Your Air Conditioner Smells Bad (+Fix)
• 11 Reasons Your Air Conditioner Is Leaking Water (+Fix)
• 15 Reasons Your Air Conditioner Is Not Cooling (+Fix)
• 18 Reasons Your Air Conditioner Won’t Turn On (+Fix)
• 12 Reasons Your Air Conditioner Won’t Turn Off (+Fix)
• 17 Reasons Your Air Conditioner Is Not Working (+Fix)

Final thoughts

An air conditioner can make loud noises, like cracking, clicking, gurgling, hissing, grinding, etc. 

There are various reasons behind a noisy air conditioner. 

You can understand the cause of the noise type.

Though the article can help you identify the right cause of the noise type, it is better to hire an HVAC expert to confirm and fix the problem. 

Calling professionals will help fix the problem faster, preventing serious problems and high expenses. 

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When summer approaches, we all want to get to a room with an air conditioning unit. But, here is the thing about these units. They do not always work properly, especially when you need them to work at their best. 

The air conditioner doesn’t work due to dead thermostat batteries, a blown-up fuse, dirty coils and filters, a faulty compressor, improper fan settings, low refrigerant, and condenser problems. To fix it, replace or repair the faulty parts and correct the settings in the thermostat and fans.

Since there are multiple reasons, you need to find the right one for your air conditioning unit. In this guide, we have shortlisted some major reasons behind an air conditioner not working and their solutions. Though you can solve some yourself, consulting HVAC experts is highly recommended while troubleshooting. 

Why is my air conditioner not working properly? 

When we say that the air conditioner is not working properly, it could mean several things. 

For example, the unit is not cooling properly, not starting when it needs to work, not ending the cycle, etc.

There could be numerous reasons behind the problem, and you must diagnose the right one and confirm it before fixing it. 

Here is a list of the expected problems behind an air conditioner not working:

1. The thermostat batteries are dead

Sometimes, we panic so much that we forget to look at the simple things. 

A thermostat with a dead battery can make your air conditioner not work properly. 

The simple solution here is to change and replace the thermostat batteries. 

While buying the batteries, make sure that the batteries match the thermostat’s make and model. 

Otherwise, it won’t work, and the problem will stay unsolved. 

Also read: 12 Reasons Your Thermostat Is Blank+Fix

2. The indoor disconnect switch is off

The indoor disconnect box is the central nervous system of your air conditioning unit. 

The switch is located in the attic or the garage.

The air conditioner won’t work properly if the switch gets bumped accidentally and turned off. 

Before troubleshooting, you must confirm that the disconnect switch is turned to the ON position. 

3. The outdoor disconnect switch is off

This switch is installed next to the air conditioning unit. 

You or someone might have turned it off during lawn maintenance or other causes, for which the air conditioner may not work properly. 

You need to check the switch to confirm the problem and turn the switch back. 

4. A tripped circuit breaker or air conditioner

If the breaker connected to the air conditioner tripped, your unit would not start. 

To confirm it, check whether the breaker connected to the HVAC system has tripped. You only need to reset the breaker. 

Turn the breaker to the off position, wait for a few seconds, and then turn it on again. 

Breakers often trip due to overloading. 

If the breaker trips again after resetting, do not reset it again. 

Instead, call for an HVAC expert to look into the matter. 

Can I reset my air conditioner?

Most times, the professionally installed air conditioners do not have reset buttons. 

Sudden power outages or surges are one of the common reasons behind an air conditioner not working properly. 

However, the problem resolves if the power remains again for a very long time.

However, checking the system after a power outage and breaker box is good. 

The power outage could sometimes be due to a tripped breaker. 

One obvious indicator is a blank thermostat.

Turn the air conditioner off at the thermostat and reset your circuit breaker. 

Please wait for 30 minutes before turning it back on. 

If you still face difficulties making your air conditioner work, call a professional before the problem worsens. 

5. Blown-up fuse

A blown-up fuse between the thermostat and the air conditioner means a bad battery. 

The unit cannot work properly to give you the desired temperature if you have a blown-up fuse in your air conditioner. 

First, you need to confirm the problem. 

Turn off the air conditioner at the breaker and pull out the fuse for a continuity test with a multimeter. 

If there is no voltage, the fuse has probably blown up. 

You need to replace the fuse with a new one with the help of an expert. 

While buying the fuse, consider buying the model that suits your unit. 

6. Blown-up transformer

The deal is the same as the blown-up fuse. 

Your air conditioner will not work unless you replace the transformer. 

Sometimes a bad contactor will also result in the same problems. 

It is generally the contactor that leads to a blown-up transformer. 

The contactor’s contacts get stuck with each other. 

So, you will have to fix the contactor too. 

Sometimes, a slight tapping helps to release the contacts. 

At other times, you need an HVAC expert’s help. 

7. Starting parts on a fritz

The air conditioners depend on two capacitors inside the outdoor unit. 

One capacitor is the start capacitor, and another is the run capacitor. 

The capacitors look like giant batteries. 

The capacitors hold the power of the air conditioner to turn it on and keep it running. 

But if the capacitors are dead or have ended their lifespan, the air conditioner will not work properly. 

Since they eventually fail, you need to hire an HVAC expert to replace the capacitors. 

8. Dirty indoor and outdoor coils 

An air conditioner will have two coils – one for the outdoor unit and another for the indoor unit. 

These coils will get dirty over time if you do not maintain the unit regularly. 

In that case, the air from the air conditioner will not be cold despite setting the thermostat to ‘cool.’ 

Due to the accumulation of dirt and debris, the system cannot remove the heat from your house, which means the unit won’t work well.

So, you must ensure regular cleaning of the coils to avoid the problem.

9. Dirty air filters

The air conditioner not working could be due to the dirty air filters inside the unit. 

Over time, the filter accumulates dirt, debris, and other air particles from the environment. 

As a result, the air cannot flow through the filter due to the blockage, affecting the unit’s cooling potential. 

Based on the filter condition, you can either change it or replace it. 

Pull out the cover plate, remove the filter, and replace it with a new one. 

Sometimes, the filters are washable and reusable. 

You can wash the filter, dry it, and put it back in place.

10. High atmospheric temperatures

Every air conditioner has a specific operating temperature for which the unit works efficiently. 

Suppose the surrounding temperature is so high that it crosses the limit of the optimum temperature. 

In that case, the efficiency of the air conditioner will reduce.

During the summers, sometimes the temperature reaches so high that it becomes very difficult for the air conditioner to reach the desired temperature and cool down your room. 

During such a condition, you might feel like the unit is not working properly. 

But that is not always the case. 

The unit works hard to reach the goal, but the surrounding temperature becomes excessive to handle.

11. Faulty compressor

A compressor is a motor that compresses the coolant to circulate it through the evaporator coil. 

If the air conditioner is not cooling, the compressor is defective, and the AC cycle gets broken.

The problem requires immediate fixation because the compressor can be expensive and an important part of your unit.

You may not be able to fix it yourself. Consider hiring a professional to deal with it.

12. The fan setting is wrong

Some users are unaware of the air conditioner’s fan settings. 

There is more than one setting. 

The AC fans have three fan settings – low, medium, and high- like the ceiling and table fans. 

If the fan speed is optimized incorrectly, the unit will not work properly. Therefore, it will create an uncomfortable environment. 

If the fan speed is high, the unit will become overactive, and the energy bills will increase. 

On the contrary, low fan speed will not absorb the humidity and give you enough cool air. 

So, the best is medium.

13. Failed condensate pump

Checking for the condensate pump is easy. 

The pump has a low lifespan because it runs both the air conditioners and the furnaces. 

The pump has a test button. 

To check the condensate pump’s condition, ensure the basin has some water, and then press the test button to see if the pump is pumping the water out.

The condensate pump can sometimes trip the unit, for which the unit will not run, and create a pool where your unit is installed.

You will see a float on the top of the pump that will be stuck and shut off the pump. 

If the float got stuck, a gentle tap should correct the problem. 

But, if it is cracked, you need an HVAC expert to replace it and make your unit work again.

14. Incorrect air conditioner size

An incorrect AC size can be the reason behind the unit not working properly. 

Different square footage will need different sizes of air conditioners, and selecting the right one is difficult. 

Getting an incorrect air conditioner size will not let your unit work properly. 

If you get a very small unit, it will work harder to give you the desired temperature but won’t be able to give you. 

It will make you think that your unit is not working properly. 

Since the unit will struggle to give you the needed temperature without stopping the cycle, it will increase the energy bills. 

If the unit is too big for your house, it will require power and struggle to stay on. 

A big air conditioner won’t allow the machine to work efficiently. 

It will constantly turn on and off and create hot spots in your room.

15. Low refrigerant 

Sometimes, you think your air conditioner is not working because it cannot give your room enough cool air. 

It is probably because of the low refrigerant. 

The refrigerant fluid eliminates the heat and spreads cool air throughout your house. 

The AC unit will not meet your expectations if the level is low. 

It could be because the fluid is leaking due to rust, erosion, or cracks. 

You need to call a professional to replace the refrigerant tank and fill up the fluid.

16. Careless outdoor landscaping

If plants and shrubs are outside near your air conditioner’s condenser unit, they obstruct the airflow and cover the unit with dirt and leaves. 

It can overburden the condenser unit and make the system fail, resulting in insufficient cooling. 

As a result, the house owner thinks the unit is not working properly.

Make sure to have a 2 to 3 feet distance between the condenser unit and the trees and shrubs. 

17. Someone damaged the HVAC components.

Sometimes, you can accidentally bust the components of the HVAC system. 

So, something happened with your unit. For example:

• The landscaper accidentally busted the refrigerant line. 
• You pulled a wire by mistake while working on some unrelated project.
• Kids threw a heavy ball or something to the outdoor unit and damaged something. 

Anything can make your air conditioner not work properly.

If you suspect any of these but cannot come to one point, call your local HVAC expert to help you.

Final thoughts

So, these are some of the common and major reasons behind an air conditioner not working properly. 

Since so many reasons exist, you must hire a professional before fixing anything. 

They can help you diagnose the main problem and fix it. 

You can prevent this by having routine maintenance of your unit. 

Consider checking it up whenever your air conditioner slows down or something you feel is incorrect. 

The best solution to all these problems is to call your local HVAC team for regular maintenance. 

The team will check your unit, detect if there is any problem or if any part requires replacement or clean up, and do as required. 

In that way, you can prevent maximum unit issues.

Everyone’s best friend is a good and efficient air conditioner during the summer. But if the unit keeps running constantly, that could be a matter of concern. Constant running of the air conditioner can increase your energy bills. 

An AC constantly runs because of a faulty thermostat, stuck compressor contactor, incorrect unit size, or wrong blower fan setting. Correct the thermostat setting and check the compressor and blower fan settings to fix it. Buy the right AC size depending on your house size. 

The list continues. This article discusses why an air conditioner is not turning off and how you can troubleshoot a few problems yourself. Even if you can fix some issues, only an expert HVAC technician will best guide you. 

Why is my air conditioner not turning off?

It is quite abnormal for an air conditioner to keep running.

Sometimes, it will keep running the whole day but fail to give the desired heat. 

And sometimes, it will run even though you have turned it off. 

It can increase the energy bills for your house without any benefit. 

Here are some of the obvious reasons behind an AC not turning off and their solutions:

1. The thermostat is set to the ‘ON’ position.

The thermostat will have an ON and AUTO setting to operate your fan. 

If your thermostat is set to the ON position, it signals your air conditioner to run constantly without stopping. 

So, your air conditioner will keep running whether you turn the unit off.

Check the thermostat setting if your air conditioning unit is not turning off. It would be best to change it to AUTO. 

When you keep the setting to AUTO, the unit will signal the fan that you can turn it on or off in sync with the air conditioner turning on or off. 

But, if the setting is already in the AUTO option, there is some other problem that you still need to find.

2. Faulty thermostat 

If the thermostat is at fault, your air conditioner will get affected and won’t stop running. 

You can check the problems by cutting the power to the air handler. 

If the condenser stops running when the power is off, the problem is with your thermostat. 

To cut the power, unplug the yellow wire connected to the Y terminal in the thermostat. 

Heat outside to check if the condenser is running or not. 

If the condenser has stopped running, but the AC is still on, you need to purchase a new thermostat and install it. 

But if the condenser keeps running, the problem is with the wiring. 

3. Damaged thermostat wiring

Over time, your thermostat’s wires will wear out and get damaged due to old age. 

The sheath of the insulation around the wires will degrade and expose the wires. 

If the exposed wires touch each other frequently, your condenser will constantly run, so your AC won’t stop running. 

Several conditions can make the wire exposed except for old age, for example:

• You have accidentally nailed a wire in the wall. 
• Rodents in the wall chewed up the wire.
• The outside wall got hit by a weed whacker. 
• The wire is at fault directly from the manufacturer. 

You can check for the damaged wire easily by taking out the thermostat cover and having a visual inspection. 

The outdoor wiring will have conduit protection. 

If there is any damage to the housing, the wires might get affected. 

If you find any damaged or loose wires, you must hire an electrician or HVAC technician to fix the problem.

4. Stuck compressor contactor

The contactor controls the electricity to the compressor. 

If the contactor is open, the electricity cannot flow to the motor. 

The electricity will flow when the contactor is closed.

When the thermostat setting is turned for cooling, the voltage is sent to the compressor contactor. 

As a result, the contactor closes and powers down everything. 

The problem occurs when the contactor contacts stick together due to excessive heating when the electricity arc passes through them. 

When the contactor remains stuck and fails to disconnect, it shuts off the power, preventing the condenser and air conditioner from stopping. 

Based on the damage level of the contactor, you can fix the problem or replace it. 

To fix it yourself, try tapping on the contactor to check if the tapping force can break the contacts apart. 

Take a small wire brush to clean them off. 

If it does not work, the contactor might have been damaged. 

You need to hire a professional HVAC to fix it.

5. Clogged ice in the evaporator coil

Clogged ice in the evaporator coil is quite common. 

Ice getting inside the air conditioner is common, but ice getting clumped up will not make your air conditioner turn off. 

When the evaporator coil accumulates too much ice, it gets frozen. 

As a result, the air conditioner cannot reach the desired temperature goal. 

It will make the unit keep running due to an incomplete cooling cycle. 

Too much ice will also cause a refrigerant leak, which means your unit will fail to cool down your room. 

You cannot fix the problem yourself. 

You need an HVAC technician to replace the evaporator coil. 

Please do not turn on the unit until it defrosts completely. 

6. Improper AC size

The air conditioner works by absorbing the warm air from your house, separating the moisture from humidity, and cooling it. 

The unit will keep doing it until the temperature reaches the desired one, i.e., the number you have set on the thermostat. 

When it reaches the desired temperature, the air conditioner will shut off. 

That is called the AC cycle. 

The cycle typically lasts between 20 to 30 minutes. 

Once the indoor temperature rises, the unit will begin another cycle. 

But, if you buy an air conditioner that is smaller than your house needs, the cycle will not end, and your air conditioner will continue to run. 

It will work very hard to reach the desired temperature to no avail. 

As a result, the energy bills will rise. 

You need to replace the unit with the right one. 

How to buy the right size of air conditioner for the house?

To get rid of all the heat inside your house, you must select an AC that suits your house. 

You need to know the BTU capacity of the unit and how much is suitable for your house.

For each ton of heat removed from the house, an air conditioner should need 12,000 BTUs. 

For larger houses, the BTU will increase. 

To select the right AC size, you must consider a few things:

• The construction materials
• Insulation type of your house
• Ceiling height
• People living in your house
• Amount of sunlight coming inside your house

You can ask for help from an expert to get the right unit size. 

7. Old air conditioning unit

Old air conditioning units will have old parts, which cause malfunctions in your unit, for which it won’t stop running. 

Some units last only for 15 years, especially in hot areas like Florida. 

Sometimes, even the most promising unit will give up due to old parts. 

In that case, you must replace your cooling unit with a new one. 

Besides, the new one will be more energy efficient than the old one, which means you can save energy bills. 

8. Dirty air filters

The air conditioner starts one cycle to reach the desired temperature. 

After that, it stops and starts again when needed. 

The dirty air filters block the airflow and prevent the AC from giving your room the desired temperature. 

As a result, the unit will work hard and keep running to give you the required chill. 

If the filters become dirty, you must replace them with new ones. 

You can also wash the filter, dry it, and return it to your air conditioner if it is reusable. 

9. Faulty fan switch limit

Even if your fan has the correct settings, the fan motor will continue running when the air conditioner is not cycling. 

As a result, the AC will keep running and won’t shut off. 

It happens when the fan limit switch is stuck in the override position. 

You can fix it by resetting the limit switch near the blower fan to stop the fan and the air conditioner from running constantly. 

10. Low fan speed

If the blower fan speed is lower than normal, the system cannot move enough cool air throughout your house. 

If this happens, your air conditioner will work harder to give you the right temperature and won’t stop its cycle.

Dirt and debris over the fan blades will make the work difficult. 

So, make sure that the fan is clean. 

To clean the blower fan yourself, follow the following steps:

• Turn off the power to the indoor unit. 
• Remove the access panel at the blower compartment. 
• Unscrew the screws holding the circuit board. Let the wires remain connected, and remove the circuit board from the way. 
• Remove the screws holding the fan assembly and carefully slide them out of the cabinet. 
• Use a soft brush and slowly clean the dust and debris over the fan blades and cabinet. 
• Keep back the blower assembly in the cabinet and secure it with the screws. 
• Repeat the same with the circuit board and secure it. 
• Screw back the access panel and turn on the power. 

11. Faulty electronic control board (PCB Assembly) or short circuit

The control board is an integral part of your air conditioning unit. 

It transfers signals and information from one part to another. 

For example, suppose the temperature is high. 

In that case, the temperature sensor will transfer this information to the electronic board to get transmitted to the cooling system. 

The control board cannot send the signal if it is broken or at fault. 

Even if you shut off the unit, the unit will keep running, waiting for the signal. 

The same occurs when there is a short circuit.

In this case, you need a specialist to confirm and fix the problem. 

Depending on the damage extent, you may need to replace the board or the entire AC unit.

12. Extreme high temperatures

Sometimes, your air conditioner will face difficulty turning off the cycle when the summer temperature is at its peak. 

The unit will keep struggling to reach the desired temperature and keep cycling and running to give you the required cold air. 

Set your thermostat temperature higher by 5-10 degrees to confirm the problem and shut off the unit. 

If the unit shuts off completely, it is a sign that your unit has been overworking.

You might need a bigger one. 

Contact your HVAC specialist to help you out here. 

Since there are multiple reasons behind an air conditioner not turning off, the specialist can help you diagnose the correct reasons and resolve them quickly. 

How to prevent the air conditioner from such problems?

You can stop your air conditioner from struggling due to the above reasons by regular unit maintenance. 

Else, you will keep facing problems besides AC not shutting off, like, not turning on, water leakage, weird noises, etc. 

Here are some preventive measures.

• Get a routine checkup for your air conditioner.
• Clean the extra dust, ice, and air particles from the unit.
• Buy a commercial-grade contactor to avoid compressor contactor problems. It might be expensive, but it’s worth it because it can stop the contactor from getting stuck. 
• Take defensive measures for your thermostat and ensure no outside force damages it. 
• Keep updated on your air conditioner’s parts. Even the slightest malfunctioning can raise problems. 

These preventive measures do not guarantee the full safety of your air conditioner. 

The measures cannot stop your unit from getting any problems, but they can delay the problem or reduce the damage level.

Final thoughts

There are many causes behind an air conditioner not turning off. 

You must find out the real cause before troubleshooting the problems. 

Otherwise, you can end up with the wrong cause and increase damage levels.

The reason could be an easier one, like a thermostat set to ON, or a difficult one, like a faulty control board, old AC unit, faulty fan switch, etc. 

Sometimes, it is just the weather or small AC, for which the unit works hard to give you the required temperature.

Since there are many reasons, you might face difficulty in diagnosing the real problem. 

In that case, you can contact your HVAC team to help you out. 

They will help you find the right cause and solve the problem faster without extra time, effort, and charges. 

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People find it difficult to stay without an air conditioning unit when the days get warmer. But, if the unit refuses to turn on, it can cause stress to you and your family. This article will explain why an AC does not turn on.

Common reasons behind AC not starting are tripped breaker, blown fuses, a faulty thermostat or blower motor, clogged condensate, dirty coils, refrigerant leak, or wire issues. To fix it, check the breaker and thermostat settings, clean the condensate and coils, and replace the refrigerant tank.

There are more problems responsible for the AC not turning on. This guide will explain the reasons and what to do with the problem. You can solve some yourself, but most issues will need expert guidance. 

Why does an air conditioning unit not turn on?

A working air conditioner is an important part of life nowadays. 

You will find it everywhere, in a shop, in a working office, or at home. 

An AC not working in the house can be dealt with. 

But if the unit does not work well in a working space or a large-scale shop, the staff and customers will suffer misery. 

The problem behind AC not working cannot be easily diagnosed, especially if there is a major one. 

Some expected reasons behind an AC not starting could be:

• Power problems
• Faulty indoor blower motor
• Thermostat problem
• Malfunctioned safety devices
• Energy saving program
• Low refrigerant
• Clogged condensate 
• Clogged air filters and drain pans
• Dead AC capacitor
• Dormancy 
• Faulty power cord or outlet
• Incorrect AC size
• Frozen evaporator coil

Since there are so many reasons, you must find the real one and treat it. If you end up treating the problem wrong, you will have to spend more time, effort, and money on solving the problem.

Let’s explore these reasons in detail.

1. Tripped circuit breaker

A common problem behind an AC not starting is a tripped circuit breaker.

Sometimes, when a breaker powers too many appliances simultaneously, it trips off because of overloading. Heavy rains and thunder are also responsible for tripping.

However, tripping keeps your unit safe from serious issues. 

If the breaker is tripped, the AC won’t start. 

Find your electrical panel and check the switch for AC. 

If it is tripped off, turn it to the on position. 

But, if the tripping is frequent, do not reset it again. The circuit is getting overloaded for some unknown reason. 

Switching the breaker on can start a fire. So, call a professional to deal with it. 

2. Condenser unit unplugged

Sometimes, we need to pay attention to simple problems. 

You may not have plugged the cord from the air conditioner into an outlet. It sometimes happens during a window AC. 

You will see a small brown cord coming out of the air conditioner to be connected to the panel on the side of your house. 

These wires may remain unplugged or get chewed, stopping the current from flowing to your AC. 

Make sure the wire is plugged in. 

If it gets damaged, you must change it by calling an expert.

3. Blown fuse

Your house will have a fuse box outside, near the condenser unit. 

If the fuse blows, your AC won’t start. 

If you suspect a blown-up fuse, you must be careful. 

Before you check, turn off the air conditioner and power supply to avoid electrocution. 

Pull out the fuses and consider a continuity test with a multimeter. 

If the fuses do not work, buy one from the hardware store. 

While buying, make sure you buy the model that suits your unit. 

Take a picture of the old make and model. 

4. Clogged air filter

A blocked air filter is another reason behind an air conditioner not starting. 

Generally, you must change the air filter every 2-3 months. 

If you have a reusable one, you can wash it, dry it, and install it back. 

Over time, the air filters can accumulate dust, debris, and other air particles and block the filter. 

This blocking will stop the airflow and freeze the coil. 

As a result, your air conditioner will stop cooling down your house. 

If the layers of ice are thick, it won’t let the unit turn on again. 

Turn off the air conditioner, and open the front panel. 

Slowly remove the filter and see if you can see through it. 

If not, you must change it. 

You can wash it and put it back if the product is reusable.

Sometimes, the filter gets broken. 

In that case, you must replace the filter. 

After you have changed, wait for the ice to defrost. 

Otherwise, you will damage the unit. 

You can use a blow dryer to speed up the process. 

5. Clogged AC drain pan

Lack of maintenance will make your air conditioner drain pan clogged by dirt, debris, and moisture, especially in areas with high humidity. 

The pan is located under the evaporator coil. 

After that, the water flows through the drain line, directed outside the house.

The drain pan has a secondary pan to prevent the pans from clogging. 

But if both are clogged, it will trigger the float switch, turning off the AC. 

The safety switch is a protection mechanism to prevent excessive leakage and damage. 

Use a wet or dry vacuum to suction out the blockage. 

Since it can be messy, you can hire a professional to do the job.

Unless you clear the pan, the AC won’t start again. 

You need to perform this task regularly. 

6. Thermostat problem

When your AC stops working, wait for some time and think about the thermostat. 

The thermostat malfunctioning will affect the air conditioning unit. 

If the thermostat is off, it won’t signal the AC to turn it on. 

Therefore, the unit will not start.

Check the thermostat batteries as well. Without a battery, the thermostat won’t work, and without the thermostat, the AC will not turn on. 

If everything is fine, check the thermostat’s functioning. 

Please set it to 5 degrees lower than the indoor temperature and check the AC after a few minutes. 

Place your hand in front of the AC vane to see if it is passing cold air. 

Check the AC components for dust buildup, blown fuses, and loose connections if the unit remains off. 

Call a professional if you cannot figure it out. 

7. Faulty control board

Most air conditioning units have a control board or printed circuit board (PCB). 

The circuit board controls the electricity and passes it to all the small parts of your unit. 

Due to this function, the problem is tricky to diagnose. 

Check whether the compressor or the fan circuits are working. 

If they are turning on, the control board is the culprit behind an AC not starting. 

Check the manual carefully if you want to solve the problem yourself. Otherwise, call for an expert’s help. 

8. Low refrigerant

The refrigerant is a cooling fluid that sends cold air throughout your house. 

The fluid is mainly responsible for providing enough cold air throughout the house. 

Low refrigerant is not because the unit uses it up. 

But, it can also be due to refrigerant leakage due to cracks or rust. 

The cracks can happen over time due to old age and corrosion. 

You need to replace the refrigerant tank and refill it. 

Please turn off the unit at the breaker box and drain the refrigerant by siphoning it with a plastic hose. 

Find signs of leakage, crack, or erosion. 

Contact your manufacturer to get the right refrigerant tank and fluid. 

You need an expert’s help to do this job. 

Once everything is done, please turn on the unit to check whether it is working.

9. Dead AC capacitor

The air conditioner’s capacitor is sensitive to heat. 

There are two types of capacitors:

• The start capacitor delivers voltage to start the motor. 
• The run capacitor supplies energy to keep the motor running.

Overheating will make your AC work harder to make the room cold and get the desired temperature. 

The unit may get very hot if it is installed on the roof. 

During extreme temperatures, you must avoid setting the temperature to the highest or lowest on the thermostat. 

It will make the unit work harder, causing an overheated or dead capacitor. 

Power outages and frequent fluctuations can also damage the capacitor. 

You can install a power surge protector to prevent the capacitor from getting affected due to power outages and fluctuations. 

Old age can cause the capacitor to die and reduce its energy. 

In that case, you have to replace it. 

You can understand old age through regular maintenance.

Replace the capacitor if it is dead. 

Do not try to replace it yourself as there are electrical charges stored. Hire an expert to do the job. 

If you suspect and confirm that the capacitor is dead, do not forcibly run the AC, as that can burn the motor. 

Replacing the motor further will be expensive.

10. Malfunctioned safety switches

There is a float switch inside the air conditioner. 

Most systems have a float or wet switch for safety, and both work to prevent excessive overflow. 

The switch activates to shut off the AC when the drain pan is filled with excessive water. 

Check your unit and find if water is pooling at its base. 

If the switch is at fault, it won’t let the AC turn on. 

You need to call a professional to confirm the problem and fix it. 

11. Dirty condenser

The outside unit of your air conditioner is called the condenser. 

It releases the heat to the environment collected by the internal unit. 

The condenser will become dirty if your AC does not receive regular maintenance. 

As a result, it will work harder to dissipate the heat because the accumulated dirt will act as an insulator. 

When the condenser draws too much current, it trips the breaker and stops the AC from turning on further. 

Only cleaning the condenser will not solve the problem. 

Besides, if a dirty condenser leads you to this place, you are late for cleaning. 

You will need a professional clean-up. 

Improper cleaning will damage the compressor coil fins, which is more destructive than an uncleaned condenser. 

You can prevent this by regular maintenance of the unit. 

Clean the condenser from time to time to prevent this problem. 

12. Damaged motor

When you hear a grinding noise from your air conditioner, it indicates malfunctioned motor blades. 

The motors remain sealed to prevent contact with any outside air, water, or dirt. 

But due to old age, the sealing will come off, and the oil sealed within the motor will come out. 

Without the oil, the motor will wear out and stop working. 

The outside air fails to evaporate the heat if the motor is damaged. 

You need to replace the motor blades if they cause problems. 

Call an HVAC team to replace the motor if the motor is at fault. 

13. Faulty power cord or outlet

Sometimes, the issue is a simple one. For example, the power cord might have been frayed and worn out. 

It happens if you have stored the unit for a long time without using it or due to frequent power outages. 

Check the cord for signs of damage. You will have to replace it. 

Sometimes, the outlet does not let the unit turn on. 

Check the outlet by plugging the cord of any other appliance. 

If the appliance does not start, then the outlet is the culprit. 

You need to call the electrician to fix the outlet and the cord.

You cannot repair the cord or the power outlet yourself. 

You could risk getting electrocuted in the process if you are not careful. 

14. Dormancy

Sometimes, AC not turning on is a dormancy problem. 

Suppose the cooling system lies idle during the winter, and you have turned it on again when summer arrives. 

In that case, the fans inside the unit find it hard to start rotating again due to the dirt buildup. 

You can call an HVAC expert to start the fans manually. 

You can solve the problem once the fan comes out of dormancy and starts on again. 

15. Improper unit size

If your AC is not turning on, it could be due to the unit’s wrong size. 

A small unit must work harder to give your room the desired temperature. 

On the contrary, a large unit will take up too much power and struggle to remain in the ‘on’ position. 

So, if the unit size is incorrect, it will not turn on after some time. 

In that case, you must replace it and buy a new one. 

You cannot, of course, do it yourself. 

Please consult an expert team before deciding and ask for the right aircon size. 

16. Your AC has run its course

If your AC has been your companion for a long time, and now it is not starting, it is simply because its lifespan has ended. 

But how do you confirm it? Here are some ways:

• The airflow will decrease slowly even after regular maintenance. 
• Your AC will need repair now and then despite the regular maintenance. 
• The bills will increase. When the lifespan ends, the AC will overwork to reach the desired temperature. For this, there will be a surge in your electricity bills.
• The AC is leaking inside too much. 
• AC will make weird noises like grinding, screeching, rattling, etc. 
• Your AC will smell bad despite regular care and cleaning. 

If your AC experiences any of the above signs and the unit is quite old, you must replace it with a new one. 

However, do not make the decision yourself. Before buying, consider consulting an expert for confirmation.

17. Energy saving program 

You can enroll to receive a discount on your energy bills if you have energy programs. 

For example, Maryland has a BGE Smart Energy Savers Program. 

Participating in this program will make the HVAC system of your house turn off during peak electrical times. 

So, if your air conditioning unit is not turning on, the reason is the energy-saving program. 

If you suspect this, wait for your AC to get turned on the next day. 

Otherwise, there is another issue. 

18. Locked aircon control

Most air conditioners are mounted on the wall and use a remote control. 

You may have accidentally turned on the locked feature in the remote. 

As a result, the unit won’t start even if you try to turn it on by powering it up. 

The remote has locked the unit to stay in such a condition. 

You can understand the problem by looking at the digital screen of the remote when you turn the button to ‘on.’

Different units have different settings. 

Usually, holding the ‘+’ and ‘-‘ signs or the higher and lower degree buttons together can disengage the lock button. 

You can check your manual before doing anything. 

Final thoughts

There are many reasons behind an AC not turning on. 

Sometimes it is for silly reasons, like a switch not turned on, a breaker tripped off, thermostat issues, cord or outlet not working, dormancy, or a lock switch engaged. 

Other times, there could be serious reasons, for example, dirty condenser, air filters, blown-up fuse, dead capacitor, clogged condensate, low refrigerant, faulty control board, etc. 

Before you troubleshoot any problem, consider finding the right one. 

You cannot do it yourself. Call an HVAC expert to help you out. 

Do not let the problem stay for a very long time. 

Otherwise, that can give rise to some other issues. 

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It is frustrating and stressful if an air conditioner does not cool down your house during the scorching summers. An air conditioner not working in the summer is the least you want. So, you must quickly identify the problem faster for a comfortable environment. 

Your air conditioner might not be cooling due to various factors, including dirty air filters, blocked condensers, dirty or frozen coils, and low refrigerant. You must regularly clean the filters and ensure no refrigerant leakage. Regular maintenance of the unit can prevent these issues.

The list continues. There are many more reasons behind an air conditioner not cooling. This article will explore all the possible reasons behind it and how to troubleshoot them. 

Air conditioner running but not cooling – What should I know?

An air conditioner is meant to eliminate the hot air and humidity from your house and spread cool air to comfort you and your house members. 

But, it can be quite frustrating if it cannot do the only duty it is supposed to. 

When your air conditioner is not cooling your house, you should ask yourself two questions:

• How long has the air conditioner been like this?
• What is the outside temperature of your region?

Some people must understand that an air conditioner can cool your room to a certain level. 

For example, if you live in areas like Orange County (California) and Seminole County (Florida), the temperature surpasses 93°F. 

So, your air conditioner will operate normally only if the temperature is below this range. 

Once the outside temperature exceeds 93 degrees, the air conditioner cannot cool down your room.

So, before you suspect any problem and try troubleshooting the problem, make sure that the problem is real. 

If the temperature is not extreme, but the air conditioner still cannot cool your house, check out the situations we shared below. 

1. Check the thermostat

Your air conditioner is running efficiently but does not cool your house properly. You need to check the thermostat once. 

Someone or you may have changed your thermostat’s temperature or fan setting. 

You only need to set the thermostat to COOL instead of FAN or HEAT. 

Sometimes, the setting is set to AUTO. When the setting is AUTO, the fan will only turn on during the AC cycles. 

Once the cycle is complete, your fan will turn off, and the unit will no longer cool your room.

If the settings are corrected, check whether the air conditioner gives enough cool air. 

If the problem remains, there is some other problem. 

Your air conditioner is not cooling could also be due to dead thermostat batteries. 

If the thermostat is blank, consider checking the batteries and changing them. 

2. Dirty air filters

Generally, you must change the air filters every 3-4 months. 

If you don’t, it will accumulate all the dirt, debris, and air particles, creating an obstacle to airflow. 

The dust accumulation will be so thick that it won’t flow the air properly, therefore not allowing the unit to cool your house. 

It will also cause the coils to freeze. 

To confirm the problem, open the cover plate of your unit, take out the filter, and see if you can see anything through it. 

You must replace it with a new one. Or, you can wash it if the product is reusable and washable. 

Wash it, dry it, and put it back. 

While installing, ensure the arrows are in the airflow direction. 

You should replace a standard 1-inch air filter once a month. 

3. Clogged coils

An air conditioner has an indoor air handler and an outdoor condenser. Both have coils that are pivotal to cooling your home to the best. 

The outdoor condenser coil will release the heat from the unit. 

But if the coil gets clogged, it cannot release the heat, keeping your house warm despite running the unit. 

You can check the coil easily by going outside and watching the condenser. 

Check for plants and shrubs as they create dirt and debris and block the airflow the most. 

Make sure there has to be a 2 to 3 feet distance between the trees and shrubs and the condenser. 

If you find dirt and debris, wash the unit from the outside using a hose. 

The indoor air handler has evaporator coils to remove the heat from your house. It will become clogged and dirty over time. 

Changing the air filters can prevent this. 

It is better to let the HVAC expert team clean the indoor coils. 

They are more delicate than outdoor ones and need special maintenance. 

4. Frozen evaporator coils

The indoor air conditioning unit will have an evaporator coil. 

If the indoor unit is a furnace, the evaporator coil will be in its cabinet outside the unit. 

If the indoor unit is a fan coil, like a part of the heat pump, the evaporator coil will be inside the fan coil cabinet. 

Warm indoor air passes through this coil, where the heat and humidity are removed from the air. 

After that, cool air is distributed throughout your house. 

The air conditioner cannot pass this cool, comfortable air to your house if the evaporator is frozen. 

Some common signs of a frozen evaporator are frost on the refrigerant tank, high bills, excessive condensate drainage, etc. 

The freezing mostly happens due to clogged air filters and drain lines.

Since accessing the evaporator coil is difficult, you need an HVAC team to fix the problem. 

5. Leaking refrigerant

The refrigerant fluid inside the copper coils helps absorb the heat from the air in the evaporator coil. 

The refrigerant tank in the air conditioner should have a specific amount of refrigerant fluid to work properly. 

If the refrigerant is low, the reason is leaking due to cracks, rust, or erosion. 

Leaking of the refrigerant fluid will badly affect your air conditioner and won’t let your room have enough cool air. 

When there is a leakage, it is very important to fix it. 

You can understand by a hissing sound coming out of the unit, and the energy bills will be very high.

You cannot fix it yourself. 

Consult a trained HVAC technician to replace or repair the refrigerant tank and refill the fluid. 

6. A bad or failing compressor

The role of the air conditioner’s compressor is to compress the refrigerant, raise its temperature and transport it to the outdoor coil. 

The procedure gathers heat from your house and releases it outside. 

The heat will not release outside if the compressor is at fault. 

Therefore, the air conditioner cannot cool down your room. 

Many people misdiagnose compressor failure. 

Some symptoms resemble compressor failure, and many other situations can cause the compressor to fail, making it difficult to identify. 

If you cannot confirm the problem but have a suspect, get a second opinion from the HVAC technician. 

Besides, the expert can fix the problem better.

7. Repair leaking ductwork

If the ductwork is very old, there could be a chance of leakage. 

A leaky duct will make the cool air escape, for which the air conditioner cannot cool down your house despite running. 

The ductwork must be sealed properly so that the cool air does not escape through the attic space. 

If your ductwork leaks, you need an air duct assessment to fix the problem. 

The team can inspect the ducts properly and replace the torn ducts. 

8. Undersized air conditioner

A small air conditioner will not make your house cool enough. 

The size of your room determines the size of the air conditioner. 

If you use an air conditioner smaller than your room, the unit will constantly struggle to make your room cool, but in vain. 

If the room is bigger, the cool air from the air conditioner won’t reach every corner of the room. 

It will keep struggling without ending the cycles, increasing your house’s energy bills. 

So, before you buy the unit, consider the house size. 

If you are naive, measure the room’s square footage and inform the HVAC company staff to help you. 

9. Bad or failing air conditioner capacitor

The outdoor fan will run, but the compressor may not. 

The reason is a bad or failing capacitor. 

The capacitors are like batteries. 

There are two of them – a start capacitor and a run capacitor. 

The capacitors power the motor in the compressor and the blower fan. 

If the capacitor is at fault, the compressor will not work well. 

As a result, your air conditioner won’t provide enough cool air in your room.

When the capacitor fails, the motor will make a humming noise.

You can identify the problem by hearing a clicking sound from your air conditioner. 

Replacing the capacitor is not your work. 

Call an HVAC team for help. 

10. Broken fan motor

Fan motors can wear and tear over time, especially if your air conditioner does not undergo regular maintenance.

Your air conditioner cannot provide enough cool air with a broken fan motor. 

You can identify the problem by hearing a buzzing sound from your air conditioner. 

Try to reset your unit by pressing the reset or overload button. 

Also, spin the fan blades clockwise. 

If it does not work well, the problem is with the fan motor. 

You need to replace the motor with the help of an HVAC team guide. 

11. Excessive ventilation in the room

The air conditioner works by dehumidifying the room where they are installed. 

The existing humid air is run through the evaporator to be chemically cooled and circulated. 

The process repeats until the room is properly cooled down and reaches the desired temperature you have set on the thermostat. 

If the rooms are not properly sealed, the cool air will escape from the open areas and won’t cool your room properly. 

So, while your air conditioner is operating, ensure that your room does not have excessive ventilation. 

12. Insufficient insulation

Some rooms of the house can be hotter than the rooms. 

In that case, the air conditioner may not cool the room properly. 

Have a look at the ductwork for insulation. 

Sometimes the insulated ducts also need exterior insulation. 

If the ducts are not properly insulated, they can heat the air too much after leaving the blower. 

If the ducts are uninsulated and your air conditioner is not cooling the room enough, consult an HVAC professional to make the insulation amendments. 

While checking for the vent insulation, hold your hands close to the joints to check for air leaks. 

13. Too many incandescent lights

Lights can heat your room to a great extent. 

If your room has too many lights, the room will be very hot. 

As a result, the air conditioner may not cool down your room properly. 

You must get rid of some lights and keep only the required number. 

You can also replace the incandescent lights with LED lights. 

They are more efficient, emit less heat, and save energy bills.

Sometimes, the rooms have windows exposed to excessive direct sunlight will also make the room hotter. 

Close the windows when your unit functions. 

14. The air conditioner is still not cooling.

When your air conditioner does not cool your room despite running profusely, try finding out what is wrong with the above-discussed points. 

You may not be able to fix them, but you can confirm it. 

If you cross-check with the above problems and have done everything you can, we recommend you contact the HVAC expert to help you out. 

If you want your air conditioner to run efficiently, you must maintain regular unit maintenance. 

Regular maintenance by the HVAC team will let you know what is wrong with your air conditioner and whether any part of the unit requires repair or replacement. 

This way, you can avoid problems. 

15. Damaged heat pump

Sometimes, the outdoor unit of your house could be a heat pump. 

The heat pump resembles an air conditioner unit but has different parts that help cool and heat your room. 

The system works like an air conditioner’s condenser unit during cooling operations. 

So, it can have the same issues, like dirty air filters and coils, refrigerant leaks, etc. 

Check the thermostat settings, air filters, and condenser unit if the heat pump does not cool your room. 

Call the local HVAC dealer to fix the problem.

Also read:

• 10 Ways To Fix Temperature Differences Between Rooms
• 12 Reasons Your Air Conditioner Smells Bad (+Fix)
• 11 Reasons Your Air Conditioner Is Leaking Water (+Fix)
• Does A Humidifier Cool A Room? (+Why You Need One)

Final thoughts

An air conditioner is needed to cool down your room. 

But if the unit fails in the one thing it is supposed to do, something is very wrong. 

Some common reasons are clogged air filters and coils, frozen evaporator coils, failed capacitors and compressors, leaking refrigerant, small units, too much light, and ventilation, etc. 

Since there are so many reasons, you need an HVAC expert to identify the real cause. 

You can confirm and fix some problems yourself, like the clogged air filters and outdoor condensers. 

Others will need professional guidance. 

Regular maintenance and servicing can prevent problems to some extent and keep your air conditioner efficient. 

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