AC Troubleshooting Tips

The intense heat of a Texas summer must make you appreciate your air conditioner. Air conditioning is not just about comfort; it can help protect you from dangerous conditions. Unfortunately, people have been hospitalized and even killed by extreme Texas heat. Air conditioning is something that you do not want to have trouble with. In this blog post, Cote’s Mechanical will describe some common air conditioning problems to help you with troubleshooting common AC issues. We’ll go over whether it is a simple repair you might be able to do yourself or something more complex that needs to be done by an HVAC professional.

Caution: Please be aware that working on an HVAC system can be dangerous. If you do not know how to do something, please reach out to a reputable professional.

1. No Cool Air? Check Your Thermostat Settings First

There are several reasons why your air conditioner is not producing cool air. It’s a good idea to start your troubleshooting by inspecting the settings of your thermostat. Ensure it is set to “cold.” If “cold” is selected on the thermostat, check the setting of the thermostat to make sure no one has changed it. If the thermostat is turned off, turn it to “heat”, or select the “constant fan” option (this is sometimes labeled as “on”). Then, turn it back to cooling operation. After the system comes on, wait for a few minutes, then see if you have cold air coming out of the registers. If you’ve got cold air, you’re good to go. If not, you’ll need to check to see if your air filter is dirty.

2. Inadequate Cooling: Clean or Replace Filters

If you’ve found no problems with your thermostat, the problem may lie in a dirty air filter. If that’s the case, the filter must be cleaned or replaced. In some cases, an air conditioner may completely stop working because of a dirty filter.

Also, if your air conditioning is not working as well as it should, it may be because of a dirty air filter. According to Energy.gov, “clogged, dirty filters reduce the amount of airflow and significantly reduce a system’s efficiency.” 

Selecting the Right Filter

Air filters can play a significant role in your home’s air quality. MERV is the industry standard for rating HVAC filters (although it isn’t the only one.) MERV stands for “Minimum Efficiency Reporting Value” and was developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). According to the Environmental Protection Agency, MERVs report a filter’s ability to capture larger particles between 0.3 and 10 microns. The MERV system goes from 1 to 20.  Filters with a higher MERV rating are better at catching certain types of particles.

ASHRAE states, “Our current recommendation is to use a filter with a Minimum Efficiency Reporting Value (MERV) of 13, but a MERV of 14 (or better) is preferred.”

However, ASHRAE also says, “Of course, the ultimate choice needs to take the capabilities of the HVAC systems into consideration. Generally, increasing filter efficiency leads to increased pressure drop which can lead to reduced airflow through the HVAC system, more energy use for the fan to compensate for the increased resistance, or both. If a MERV 13 filter cannot be accommodated in the system, then use the highest MERV rating you can.”

It is best to consult an HVAC professional to determine the right air filter for your HVAC system.

3. Uneven Cooling: Ensure Proper Airflow and Ventilation

Uneven cooling in your home can be a real hassle. It’s not fun having a room in your house that won’t cool while others have plenty of cold air. Not only can it make you uncomfortable, but it can also cause your energy bills to go up.

There are several causes for uneven cooling. In the following section, we will cover some of them. Please note that this list is not conclusive.

Ducts are Leaky or Damaged

Old, faulty, or leaky ducts reduce air circulation, preventing rooms from being effectively cooled and reducing the efficiency of the system. Have an HVAC professional inspect the ducts and get them working as they should.

Incorrect Insulation

If the insulation in your home is insufficient, badly installed, or worn (especially in your attic), it is more difficult to regulate temperatures indoors, causing cooling to be uneven. Working with an insulation professional can get you the correct insulation your home needs.

Filters are Clogged

Filters that are clogged or dirty are the cause of multiple HVAC problems, such as uneven temperatures. Regularly replacing filters can help prevent this. If you don’t know how to do this, please seek out the help of an HVAC professional.

Vents are Closed or Blocked

Dirt and debris can accumulate over time and block vents and air ducts, leading to uneven temperatures in your home. Regular maintenance by an HVAC professional can help keep ducts and vents clear.

Check to see if the vents are closed or if something is blocking them, such as furniture or fixtures. You may need to have your furniture or other fixtures rearranged away from your vents so they can do their job.

The Air Conditioner Unit is Old or Aging

If you are experiencing uneven cooling from an air conditioner that is over 10 years old, it might be a sign to replace your air conditioner. Air conditioner units that are old or aging have a hard time functioning effectively and experience a decline in their ability to cool a home, leading to uneven temperatures. Be sure to have any air conditioner replacement done by a licensed HVAC technician.

Issues with Zoning

If your home has cooling zones and you are experiencing uneven cooling, it may be because of malfunctioning thermostat sensors or trouble with duct dampers. You’ll need an HVAC professional to resolve these issues.

Insufficiently Sized Air Conditioner Units

If an air conditioner unit is too small or too large for a home, it may fail to cool the entire house while straining the system, resulting in frequent repairs.

If you are having trouble with uneven cooling and don’t know why, contact an HVAC professional to see if your air conditioner is the right size and has been installed correctly.

4. Unusual Noises? Inspect and Address AC Components

When you have an air conditioner making loud or unusual noises, that’s a sign of trouble with the unit. On the bright side, the noise the air conditioner is making can give you an indication of what is wrong with the unit. Please be advised that air conditioner maintenance or repair is NOT something you should attempt yourself. It is always best to contact a reputable technician.

In the following section, we’ve compiled a list of common sounds an air conditioner might make when it is having a problem and what the cause might be. Please note this list is by no means conclusive.

The Air Conditioner Makes a Rattling or Banging Noise

If you’ve got an air conditioner noise that sounds like an aggressive banging, it may likely be an issue with the condenser. However, this is not necessarily the case. Below are several possible reasons why your air conditioner is making a rattling or banging noise.

The Condensor has Dirt Particles Stuck in It

A banging or rattling noise from an air conditioner can be as simple as leaves, sticks, or other dirt particles stuck in the condenser. 

The Solution

As the condenser cover will need to be taken off to remove the debris, a professional should handle this.

There are Loose Screws

Rattling noises are often the result of loose screws. The vibration of inside and outside air condition units can lead to screws loosening over time. 

The Solution

The screws will need to be tightened. A professional should handle this.

A Compressor or Fan Motor is Broken

If your air conditioner makes a banging noise when it is starting, this may be because the compressor is broken. If there is a loud noise coming from inside of the unit, the cause of the banging noise may be a motor imbalance or a broken fan motor. 

The Solution

Compressors and motors should only be worked on by HVAC professionals.

Replacing the compressor is a costly endeavor. If your air conditioner unit is over 10 years old, it is better to replace it than repair it.

In the event your HVAC compressor comes with a lifetime warranty, you can look at having it repaired, as you will only need to pay for labor. By working with an HVAC professional, you’ll be able to determine what the problem is and whether the air conditioner unit should be repaired or replaced.

CAUTION: Never inspect a running fan motor, as it can lead to severe injury.

The Air Conditioner makes Squealing or Screeching Noises

An air conditioner making high-pitched squealing or screeching noises can have multiple causes.

Worn Fan Motor Bearings

If you hear a metal-on-metal sound when turning on your air conditioning, it means the fan motor bearings are worn.

The Solution

An HVAC professional will need to clean, lubricate, or replace the fan motor bearings.

Broken or Worn Out Fan Belt

A squealing noise may be the result of a broken or worn-out fan belt. This noise is most common with air conditioners that have ducted or central air. In older models, the motor and fan are connected by a belt—which can wear out. High humidity levels can cause the belt to expand and contract causing a displeasing sound.

The Solution 

Have a licensed HVAC professional repair or replace the belt.

The Compressor Unit has High-Pressure

If your air conditioner has a high-pitched squealing noise, it is because a high amount of pressure has developed inside your compressor. 

The Solution

Shut off the air conditioner immediately—the high-pressure build-up can create an explosion. Contact a licensed HVAC professional ASAP. Don’t use the air conditioner until it is repaired.

The Air Conditioner is Making a Loud and Rhythmic or Pulsating Noise

While there may be nothing wrong with an air conditioner that makes slow pulsating noises, a loud and rhythmic noise is a sign of a problem.

Loose Coil or Blade Fan

The noise may be coming from a coil or blade fan that loosened up over time. 

The Solution

The screws will need to be tightened by an HVAC professional.

Pulsating Plastic Base of the Air Conditioner

If your air conditioning system is on top of a plastic base, the motion created by the compressor may cause the entire unit, including the base, to pulsate.

The Solution

Look into having an HVAC professional replace the plastic base with a wooden base to reduce vibrations.

Refrigerant Lines Making Contact with the Walls of the Air Conditioner

If a refrigerant line is touching an air conditioner wall, it can result in friction and vibrations between the line and wall—creating a pulsating noise. 

The Solution

Have an HVAC professional move the refrigerant line or lines away from the wall slightly and add a foam or rubber material for insulation.

The Air Conditioner Produces a Hissing Noise

Loud hissing noises coming from your air conditioner can be caused by a number of issues.

Refrigerant that is Leaking

The hissing sound may be due to a refrigerant leak. If a refrigerant line becomes damaged or deteriorates, leaking may occur.

The Solution

As with all refrigerant problems, you’ll need to contact an HVAC professional to resolve it.

A  Compressor Valve Leak

A leaking compressor valve can also be behind the hissing noise. The pressurization of the refrigerant is controlled by the compressor valve.

The Solution

You’ll want to contact an HVAC professional ASAP, as this can cause major damage.

High Compressor Pressure

If it sounds like the hissing noise has turned into a shrieking sound, it is a problem with the compressor. High pressure may be built up in the outdoor air conditioner unit.

The Solution

Shut off the air conditioner immediately since the high-pressure build-up can cause an explosion. Contact an HVAC professional ASAP.

The HVAC Unit Makes Clicking Noises

While it is normal to hear a clicking noise when a cooling cycle starts and ends, a clicking noise that doesn’t go away isn’t normal. There can be a number of reasons for this.

Air Conditioner Fans are Obstructed

If the clicking noise is coming from the outdoor unit, there’s a good chance its fans are obstructed. 

The Solution

The obstruction will need to be removed by a professional. As this requires accessing the fans, you’ll need to contact an HVAC professional to do this.

The Capacitor is Losing Charge

The clicking sound may be due to the capacitor losing its charge over a period of time. In the event this occurs, the capacitor won’t be able to power the compressor. The clicking noise is the result of the outdoor unit trying to unsuccessfully turn on.

The Solution

As with all air conditioner electrical issues, you’ll need to enlist the help of an HVAC professional to replace the capacitor.

The Electrical Signals have a Fault

If the electrical signals are faulty, they may turn the switches on and off, creating a rapid clicking noise.

The Solution

Since small sparks may occur, you’ll have to shut off the unit immediately and call an HVAC professional. Sparks can create a dangerous situation. Don’t use the air conditioner until it is repaired.

The Air Conditioner Fan is Loose

If the clicking noise is coming from your outdoor air conditioner unit; it may be because the air conditioner fan has come loose and is hitting the outdoor unit’s case.

The Solution

Contact a reputable HVAC professional, they will be able to determine if the fan is able to be tightened up or if a new one will be needed.

The Thermostat is Malfunctioning

If your thermostat is malfunctioning, you won’t be able to turn the unit on, and there will be a loud clicking noise. Hearing a soft clicking sound is normal when a thermostat is working as it should. When there is an issue with the wiring or the relay is broken, the relay will keep sending power (loud noises will occur) but the unit will not turn on. 

The Solution
You will need to contact an HVAC professional. 

The Air Conditioner is Making a Whistling Noise

A whistling noise coming from your air conditioner may not be as bad as other noises an air conditioner could make. However, it still signifies a problem. There are a few reasons why an air conditioner could be making a whistling noise.

A Leaking Air Conditioner Duct

The leaking central air conditioner duct may sound like a person whistling. Not only does it make a noise, but it also results in increased energy bills and energy loss.

The Solution

You’ll need to get an HVAC professional to make sure the ducts are correctly sealed.

The Air Conditioner Airflow has an Obstruction

If your air conditioner’s air flow is blocked by an obstruction, the lack of airflow will result in the blower motor having high pressure that creates high-pitched whistling sounds. Dirty air filters prevent air from moving through them as they should, which means the blower motor will have to forcefully pull air into the air conditioner unit. Whistling noises occur as the air moves through the cracks.

The Solution

The air conditioner filter will need to be regularly changed or cleaned. If you don’t know how to do this, please contact an HVAC professional.

The Air Conditioner has a Humming Noise

While soft humming sounds from an air conditioner motor are normal, humming noises that start getting loud are an indication of a problem. There are several reasons why your air conditioner makes a humming noise.

The Lubrication Level’s Too Low

If the air conditioner motor is in need of lubrication, it will make a humming noise. If the air conditioner motor continues to run without resolving the issue, it will begin making a loud grinding noise—not something you want to happen!

The Solution

You’ll need to contact an HVAC professional to lubricate the motor.

The Contactor has Failed

If your air conditioner unit experiences a contactor failure, humming noises will occur as the air conditioner receives power but is unable to turn on. If the issue is not fixed, the humming sound may turn into a loud buzzing sound.

The Solution

As with other electrical issues, you’ll want to have a qualified professional repair it. 

Fin Coils are Bent

Bent fin coils may make a humming noise.

The Solution

Have a reputable HVAC professional straighten the coils. This is not something you should do yourself.

The Air Conditioner Makes a Cracking Sound

If you have your air conditioner’s temperature is set too low, the fins have become dirty, or moisture isn’t draining properly, your air conditioner’s evaporator coils may freeze. When ice falls from a frozen coil, it may make a cracking sound, which makes an echo noise that travels through the system.

The Solution

As fixing this is complex, you’ll need to contact a reputable HVAC professional.

The Air Conditioner has a Buzzing Noise

Hearing a buzzing when your air conditioner starts may be a sign of several problems.

A Compressor that is Malfunctioning

If your air conditioner compressor is making noise, there’s a good chance it malfunctioned. If it has stopped working but is still getting power, there will be a buzzing noise.

The Solution

An HVAC professional will need to replace the compressor.

Loose parts 

The buzzing noise from your air conditioner may be the result of vibrations from loose parts.

The Solution

An HVAC professional will need to inspect the parts and tighten any if needed.

Capacitor Malfunction

If a capacitor goes bad, it can stop the fan from turning on and create a buzzing noise because of friction. 

The Solution

It will need to be inspected by an HVAC professional, who will let you know if it needs to be repaired or replaced. 

Defective Motor

A malfunctioning HVAC motor may be the cause of the buzzing sound. Also, a buzzing noise can occur if the copper linesthat connect to your air conditioner rub against each other or have obstructions near them.

The Solution

You’ll need to have an HVAC professional repair or replace the motor. If copper lines are the issue, an HVAC technician can make sure they are insulated properly. An HVAC technician can also help minimize metal-on-metal contact.

The Contactor has Failed

If a contactor wears down or malfunctions, it can prevent power from flowing. An HVAC unit that is trying but unable to start up because of a malfunctioning contactor will produce loud buzzing noises.

The sound begins as a hum, but if the problem is not corrected, it may turn into a loud buzzing noise.

The Solution

You will need to contact an HVAC professional to repair it.

Wires are Loose

A steady buzzing noise from an air conditioner is probably due to exposed wires loosening.

The Solution

Shut off the air conditioner immediately since there is a high probability of a dangerous electric spark. Have the wire or wires fixed by an HVAC professional before the air conditioner system is used again.

Air Conditioner Parts are Freezing

Freezing air conditioner parts may be the cause of an indoor air conditioner unit buzzing. There are several reasons why an air conditioner is freezing, including having the air conditioner’s thermostat set too low, low refrigerant level, etc.

The Solution

An HVAC professional will need to inspect the air conditioner, as there are a number of potential causes for freezing parts.

The Air Conditioner Unit is Making a Grinding Noise

If your air conditioner is making a grinding noise, it may be due to trouble with a motor or compressor. 

Compressor Trouble

If the outside unit has a grinding noise coming from it, it may be due to a compressor issue. 

The Solution 

An HVAC professional should be contacted to work on it. Generally, the HVAC professional should replace the motor instead of repairing it.

A Motor Failure

Grinding sounds from the inside air conditioner unit may be due to a motor failure.

The Solution

The system will need to be worked on by an HVAC professional. By having regular motor maintenance performed by an HVAC professional, you can reduce the likelihood of this occurring.

The Air Conditioner has a Gurgling or Burbling Noise 

Gurgling and burbling noises can easily be mistaken for one another, and they may indicate the same problem. The following are possible reasons for the noises.

Refrigerant Lines have Improper Sealing

These noises often indicate a problem with refrigerant. A gurgling sound occurs when air becomes stuck in refrigerant lines. If there is a refrigerant leak, it could make a burbling noise in addition to a hissing sound.

The Solution

An HVAC professional will have to correctly seal the lines.

Your Air Conditioner has Excessive Moisture

Bubbling sounds may be due to excessive moisture in the air conditioner. Moisture build-up may be caused by blockage in the condensation line. As the water cannot leave the line, it causes gurgling and bubbling noises.

If the condensation pump becomes damaged, the same problem may occur. Excessive moisture in the condensation pump may lead to burbling noises.

The Solution

An HVAC professional will need to inspect and repair the unit.

A Dripping Sound is Coming from Your Air Conditioner

If you hear a dripping sound coming from your air conditioner, it could either be a problem or just due to excessive moisture dropping into the drip pan—which is normal. However, it can be a problem if the dripping sound is due to excessive condensation.

A Large Amount of Condensation 

A large amount of condensation may make the trip pan overflow. 

The Solution

You will need to empty the drain pan. Please take care when doing so. If you don’t know how, be sure to reach out to an HVAC professional. 

Please note a high amount of condensation is most likely a sign of a problem with your air conditioner. You’ll need to get an HVAC professional to inspect it.

Air Conditioner Coils are Freezing

The dripping noise may be caused by ice melting off of frozen coils. There are a number of reasons why the coils can be freezing, such as a malfunctioning thermostat or dirty air filters.

The Solution

Contact an HVAC professional for an inspection.

5. AC Leaking? Examine and Clean the Condensation Drain Line

When an HVAC system cools or heats air, humidity is produced. That causes condensation to be produced. A condensation drain line allows the condensation to drain outside your home—when it is working correctly. Regular maintenance by qualified HVAC professionals can help stop problems before they turn into bigger issues.

In the event a condensation drain line is clogged, water will start to build up. This can lead to leaks and possibly damage your HVAC unit or home.

Signs your Condensation Drain Line is Clogged

There are a number of signs of a clogged drain line to look out for. 

The following are several of the possible signs your drain line is clogged:

• There is a moldy, musty smell by the indoor unit or from the air coming from the vents or registers.
• The indoor unit has standing water near it.
• The areas near the indoor unit have water damage.
• The air conditioning isn’t cooling your house.
• The air conditioning system shuts down or won’t turn on.

If any of this happens to your air conditioning, you need to contact an HVAC professional who can clean a clogged drain line.

Cleaning a Condensation Drain Line

Cleaning a condensation line is best left to the professionals. They have the tools and know-how to do the job right.

The following are the general steps an HVAC professional will take when cleaning out a drain line.

1. The Technician Will Power Off The Air Conditioner Unit

Even if it is not running, the HVAC technician will shut off the power to the air conditioner unit. Doing this is important for the safety of the technician and protects the HVAC system from condensation damage.

2. The Technician Inspects the Drain Pan

The technician will find the drain pan and check if it has standing water. If water is found in the drain pan, the technician can get the water out using a wet vacuum or rags. Once the water has been removed from the drain pan, it is important that the technician cleans it thoroughly to help keep mold from forming.

3. The Technician Unclogs the Condensation Drain Line 

The technician will start by removing any visible blockage from the air conditioning drain or the opening of the pipe drain. A technician will most likely use a shop vac or a wet vac for the harder-to-reach debris. They may also use a tool such as a garden snake or a plumber’s snake. If they are able to retrieve the blockage, they should see a dark mass that was either sucked up into a vacuum or pushed out the other end of the condensation drain line.

The technician may then test to see if the drain line is clear by pouring a little bit of clean water into the drain to see if it is able to flow out.

4. The Technician Cleans the Condensation Drain Line

Once the technician has removed any blockage, they’ll most likely thoroughly clean the condensation drain line with a cleaner that is commercially available and made for use with PVC pipes. 

If you ask your technician to show you how they may teach you how to pour a mild cleaning agent (such as distilled vinegar) into the condensation drain line periodically so you can do some cleaning in between maintenance appointments.

5. Finishing Up

Once the technician cleans and tests the condensation drain line to make sure it is working, they will replace or reinstall any parts they had to remove, turn the power back on for the system, and make sure everything is working correctly.

HVAC Maintenance Tips

Over time, HVAC units can lose efficiency and have parts get worn out. This can lead to higher utility bills, expensive repairs or replacements, and downtime. In the following section are several steps that can be taken to help maintain your HVAC system. If you don’t know how to do something, it is critical that you hire a certified professional.

• Clean out your air conditioner’s outside unit by removing dirt and debris. Don’t try to take off the air conditioner’s cover to clean underneath it. Have an HVAC professional do that.
• Change the air filters every three months or more, depending on your situation.
• Turn off the air conditioner when you don’t need it.
• Open up the air vents throughout your house.
• Have the HVAC unit inspected annually, and be sure to have a professional conduct regular maintenance.
• Be proactive about contacting an HVAC professional in the event of leaks, damaged parts, and strange noises to prevent further damage.

HVAC Service in Sanger, Texas

If you have HVAC problems that are too complex to handle yourself or you want the peace of mind of professional work, the team at Cote’s Mechanical is ready to help. We are your go-to residential and commercial HVAC team for Dallas-Fort Worth. From air conditioner maintenance to air conditioner repair, we get your AC working as it should so you can stay safe and comfortable in the harsh Texas heat. We offer free estimates on new installations and free service calls with all repairs. We also provide 24/7 emergency HVAC repairs and inspections.

We are proud to be your Sanger HVAC company. Contact us for fast and professional service.

FAQs: AC Troubleshooting Tips

Additional Resources:

• Preparing Your Air Conditioner for a Hot Texas Summer
• Why Is my Air Conditioner Being Noisy?
• How Long Can I Expect My Furnace to Last?
• Common Air Conditioning Problems and Solutions
• Do I Need my A/C Unit Repaired or Replaced?