AC Repair & Troubleshooting Guide: Common Issues & Tips

Your air conditioner is essential for keeping your home cool and comfortable, but like any system, it can develop issues over time. Regular maintenance and timely repairs help prevent costly breakdowns, but when problems arise, knowing how to troubleshoot your AC can make all the difference especially if immediate professional help isn’t available.

While most AC repairs require specialized tools and expertise, there are basic steps homeowners can take to identify issues and even restore some functionality in a pinch. Understanding how your system works what powers it on, what shuts it off, and what common failures look like can help you make informed decisions about repairs.

Western Heating, Air & Plumbing has created this comprehensive AC guide. Whether you need quick troubleshooting tips or want to know when to call a professional, this guide will walk you through the essentials for keeping your home cool and comfortable year-round.

Understanding the Basics of Your AC Unit

Every air conditioning unit operates with a few key components—the compressor, condenser, evaporator coil, and refrigerant—all of which play a vital role in the cooling process. This includes our advanced models at Western.

The compressor starts the cooling cycle by pressurizing the refrigerant, which then flows to the condenser coil. Here, heat is released as the refrigerant changes from a high-pressure gas to a liquid. The cooled refrigerant then moves to the evaporator coil, which absorbs heat from your indoor air, lowering the temperature before the system circulates cool air throughout your home.

Other essential components include air filters and fans, which help maintain efficiency. Clogged filters filled with dust and debris restrict airflow, forcing the system to work harder and reducing overall performance. Regular filter maintenance is crucial for keeping your AC running smoothly and efficiently.

How Does The Air Conditioning System Work?

Air conditioning systems help homeowners and businesses maintain a comfortable indoor temperature, especially during hot weather. An AC unit creates a cooler, more livable environment while improving indoor air quality.

All air conditioners operate on the same basic principle, regardless of size or model. They use a refrigerant cycle to absorb heat from inside your home and release it outdoors, leaving behind cooler, drier air. While AC units come in various sizes and designs to fit different spaces, their electrical and mechanical functions remain the same.

Choosing the right AC system ensures efficient cooling and energy savings, making it a wise investment for comfort and cost-effectiveness.

Key Components of an Air Conditioning System

Understanding how your AC unit works can help you spot potential issues early. If you hear unusual noises or experience inconsistent airflow, knowing these components can make it easier to communicate with your technician for a faster, more efficient repair.

Here are the six primary components of every air conditioning system:

• Compressor — The compressor pressurizes the refrigerant, transforming it from a gas to a liquid and back again. This process allows the system to absorb heat from your home and release cool air.
• Condenser Coil — Located in the outdoor unit, the condenser coil releases the absorbed heat outside, allowing the refrigerant to cool down and cycle back into the system.
• Evaporator Coil—The evaporator coil in the indoor unit absorbs heat from the indoor air and cools it before it’s distributed throughout the home.
• Expansion Valve — This component regulates refrigerant flow into the evaporator coil, ensuring the proper amount enters the system to maintain efficient cooling.
• Air Handler/Fan — This part circulates indoor air over the evaporator coil, allowing the cooled air to be distributed throughout your home through your ductwork.
• Thermostat — The thermostat is the control center of your AC system. It allows you to control your desired indoor temperature.

Understanding these components will help you better understand how your AC functions and help diagnose minor issues before they become significant problems.

Types of AC Systems

Choosing the right air conditioning system depends on your home size, layout, and cooling needs. Whether you need whole-home cooling or targeted temperature control, there’s a system that fits your lifestyle. Western installs and services various energy-efficient AC systems to keep your home comfortable year-round.

Central Air Conditioning

A central AC system is the most common choice for large homes. It uses a network of ductwork to distribute cool air evenly throughout multiple rooms. These systems are powerful and efficient and work well in hot, dry climates like Utah.

Heat Pumps

A heat pump provides cooling and heating, making it a versatile and energy-efficient choice for year-round comfort. It works by transferring heat rather than generating it, reducing energy costs. For homes with solar power, heat pumps offer even more significant savings. However, in Utah’s cold winters, heat pumps often need to be paired with a traditional furnace for reliable heating when temperatures drop belw freezing.

Ductless Mini-Split Systems

Ductless mini-splits consist of an outdoor compressor and one or more indoor air handlers mounted in different rooms. These systems are ideal for homes without existing duct work. They allow individual temperature control in each space, making them great for home additions, garages, or multi-zone cooling.

Evaporative Coolers (Swamp Coolers)

Evaporative coolers use water to cool the air. However, they lose efficiency as humidity levels rise indoors and outdoors, making them less reliable for whole-home cooling. These systems also require open windows or vents for airflow, which can introduce dust, allergens, and outdoor pollutants. Western does not service evaporative coolers, but we’re happy to help you explore more effective, energy-efficient cooling options for your home.

If you’re unsure which system is best for your home, our experts at Western can help you find the perfect solution for comfort, efficiency, and long-term savings. Choosing the right air conditioning system depends on your home size, layout, and cooling needs. Whether you need whole-home cooling or targeted temperature control, there’s a system that fits your lifestyle. Western installs and services various energy-efficient AC systems to keep your home comfortable year-round.

Most Common AC Repair Problems

Below are the most commonly serviced AC problems we see at Western:

1. Dirty Air Filters

Dirty air filters are the most common cause of AC problems and can significantly impact your system’s performance. When filters become clogged with dust, pet dander, and debris, they restrict airflow, forcing your AC to work harder to cool your home. This reduces efficiency and can lead to higher energy bills, frozen coils, and even system breakdowns. A clogged filter can also reduce your indoor air quality, circulating allergens and pollutants throughout your home. Replacing your air filter every 1-3 months is one of the easiest and most effective ways to keep your AC running smoothly and avoid costly repairs.

2. Thermostat Problems

Thermostat issues are a common culprit behind AC problems and can often be easily fixed.  In some cases, dust buildup, faulty wiring, or outdated models can cause incorrect temperature readings, making your system cycle on and off more or less than it needs to. If troubleshooting doesn’t resolve the issue, a professional inspection can determine if your thermostat needs recalibration, repairs, or an upgrade to a smart thermostat.

3.  Refrigerant Leak

A refrigerant leak is a serious AC problem that can reduce cooling efficiency, raise energy bills, and even cause system failure. Refrigerant is essential for absorbing heat from your home and releasing it outside, so when levels drop due to a leak, your AC struggles to cool effectively.

Leaks often occur when refrigerant lines deteriorate over time. This deterioration can be caused by corrosion, vibration, or physical damage to the coils and connections. Exposure to moisture, fluctuating temperatures, pests or pets can also contribute to wear and tear, leading to slow leaks that worsen over time. In some cases, improper installation—such as loose fittings or poor soldering—can result in leaks that show up shortly after a new system is installed.

If you notice weak airflow, warm air coming from your vents, or hissing noises near your AC unit, it could indicate a refrigerant leak.  A professional HVAC technician must locate and repair the leak, then recharge the system with the correct amount of refrigerant to restore efficiency and prevent further damage.

4. Electrical Problems

Electrical problems can cause your AC to malfunction, short cycle, or fail to start altogether. Issues like loose wiring, faulty capacitors, tripped breakers, or worn-out contractors can prevent your system from getting the power it needs to run efficiently. Over time, electrical components can deteriorate due to heat, vibration, or power surges, leading to frequent shutdowns or inconsistent cooling.

Adding an Easy Start device is one way to boost efficiency and reduce system strain. This upgrade lowers the power surge needed when your AC starts up, reducing wear and tear on electrical components and making your unit run smoother, quieter, and more efficiently.

We also recommend installing a surge protector for your AC unit and home. Power surges from lightning, grid fluctuations, or electrical storms can damage your HVAC system and other appliances. A surge protector helps prevent costly repairs and extends the lifespan of your AC and other essential home electronics. If your AC struggles to turn on, frequently trips breakers, or has inconsistent cooling a professional inspection can identify and fix underlying electrical issues before they lead to major failures.

5. Frozen Evaporator Coil

A frozen evaporator coil prevents your AC from adequately cooling your home by blocking airflow and reducing heat absorption. When the coil freezes, it restricts the refrigerant cycle, causing your system to struggle, blow warm air, or shut down entirely. Dirty air filters, low refrigerant levels, or airflow obstructions can cause this. If ignored, a frozen coil can lead to compressor damage, resulting in costly repairs or even complete system failure.

6. Clogged Drains

A clogged condensate drain can cause serious AC issues by preventing excess moisture from draining properly. When the drain line gets blocked by dirt, algae, or debris, water can back up into your system, leading to water damage, mold growth, and even system shutdowns. Many modern AC units have a safety switch that turns the system off when a clog is detected to prevent overflow. Regular maintenance, including flushing the drain line, helps prevent clogs and keeps your AC running smoothly.

7. Faulty Capacitors

A faulty capacitor can prevent your AC from starting, cause it to short cycle, or cause it to struggle to maintain consistent cooling. Capacitors store and release electrical energy to power the compressor, fan motors, and blower, so when they weaken or fail, your system may hesitate to turn on, make clicking noises, or shut off unexpectedly. Over time, capacitors can wear out from heat, power surges, or age, leading to reduced efficiency and potential system failure. Regular inspections and timely replacements help keep your AC running reliably.

Signs Your Air Conditioner Needs Repair 

Your air conditioner works hard to keep your home cool, but like any system, it wears down over time. Ignoring minor issues can lead to major, expensive repairs or a complete system failure. The good news is that your AC often gives warning signs before breaking down. Recognizing these red flags early can help you avoid costly repairs and keep your home comfortable. Here are some key signs that your air conditioner may need professional attention.

1. Warm Air

One of the first signs of AC trouble is warm air blowing from your vents. Sometimes, this can be fixed by changing a dirty air filter, which may restrict airflow. If your unit freezes, run the fan-only mode to thaw it. A technician can inspect it only after it has fully defrosted. Call the professionals at Western for a deeper diagnosis if these steps don’t resolve the issue.

2. Unusual Noises

Strange sounds coming from your AC are often a warning sign of mechanical issues. Different noises can indicate specific problems:

• Grinding or scraping – This may signal worn-out motor bearings or a failing blower motor.
• Banging or clanking – Often caused by loose or broken components, such as a disconnected fan blade or a failing compressor.
• Squealing or screeching –  Typically indicates belt or motor issues, such as a worn-out belt or a malfunctioning fan motor.
• Hissing  – This could indicate a refrigerant leak or high internal pressure in the compressor.
• Clicking – A repetitive clicking sound may be an electrical issue, like a failing capacitor or a faulty thermostat.

If you hear any of these noises, turn off your system and call a professional to prevent further damage.

3. Bad Odors

Unpleasant odors coming from your AC can be a sign of underlying issues that need attention. A musty or moldy smell indicates mold or mildew growth in the ductwork or evaporator coils due to excess moisture. A burning smell could mean overheated electrical components, such as a failing motor or wiring issue. If you notice a rotten egg odor, this could signal a natural gas leak, which requires immediate professional attention. Even a chemical or vinegar-like smell may indicate a refrigerant leak. If your AC has bad odors, it’s best to shut it off and have a professional inspect the system to prevent further damage or potential health hazards.

4. High Electric Bill

A sudden spike in your electric bill can indicate that your AC isn’t running efficiently. When your system works harder than usual, it consumes more energy, often due to dirty air filters, low refrigerant levels, failing components, or poor airflow. An aging unit may also struggle to maintain the set temperature, leading to longer run times and increased costs. If your bill is noticeably higher without a change in usage, it’s a good idea to have a professional inspect your AC to identify and fix any problems before they lead to costly repairs or premature system failure.

5. Leaks or Excess Moisture

Leaks or excess moisture around your AC unit can signal a problem that needs attention. A clogged condensate drain is a common culprit, causing water to back up and pool around the system. Excess moisture can lead to mold growth and water damage if left unchecked. In more serious cases, a refrigerant leak could be to blame, affecting your AC’s cooling ability and posing health risks. If you notice water or moisture buildup near your unit, it’s best to schedule an inspection to prevent further damage and keep your system running efficiently.

6. Weak or No Airflow

Weak or no airflow from your AC vents is a clear sign that something isn’t working correctly. A clogged air filter is often the cause, restricting airflow and making it harder for your system to cool your home. Other potential issues include a malfunctioning blower motor, blocked ductwork, or frozen evaporator coils. Poor airflow forces your AC to work harder, leading to higher energy bills and potential system failure. If you notice weak airflow or certain rooms not cooling properly, it’s time to have a professional diagnose the issue before it gets worse.

7. Frequent Cycling

Frequent cycling, or your AC turning on and off more often than usual, can indicate an underlying issue. This problem, known as short cycling, can be caused by an oversized unit, a faulty thermostat, low refrigerant levels, or a clogged air filter. Short cycling reduces efficiency and puts extra strain on your system, leading to higher energy bills and potential component failure. If your AC is cycling too frequently, it’s best to have a professional inspect it to prevent unnecessary wear and costly repairs.

What Are the Benefits of Regular AC Maintenance?

Regular AC maintenance is essential for keeping your system running smoothly and efficiently.  Scheduling professional maintenance offers several key benefits:

Prevents Breakdowns: Catching minor issues early helps avoid costly repairs and unexpected system failures.

Increases Energy Efficiency: A well-maintained AC runs more efficiently, reducing energy consumption and lowering your utility bills.

Improves Air Quality: Cleaning and replacing filters removes dust, allergens, and pollutants, leading to cleaner, healthier indoor air.

Extends the Life of Your AC: Regular tune-ups reduce wear and tear, helping your unit last longer and delaying the need for a replacement.

By keeping up with routine maintenance, you can ensure your AC provides reliable comfort, better air quality, and long-term savings for years to come.

Why You Shouldn’t Try to DIY Serious AC Issues

While changing an air filter or adjusting your thermostat is simple, serious AC issues should never be a DIY job. Air conditioning systems are complex, with electrical components, refrigerant lines, and mechanical parts that require professional knowledge to handle safely. Attempting to repair refrigerant leaks, faulty wiring, or compressor issues on your own can lead to further damage, void warranties, or even pose safety risks like electrical shocks or refrigerant exposure. Professional HVAC technicians have the tools, training, and experience to accurately diagnose and fix problems, ensuring your system runs safely and efficiently. If your AC isn’t working properly, calling a professional is always the safest and smartest choice.

AC Repair FAQs

You’ve got questions, and we’ve got answers. Here are a few commonly asked questions we receive from our AC repair customers in Utah:

How Long Does an AC Repair Take?

The time it takes to repair an AC system depends on the type and severity of the issue. More complex repairs can take a few hours, like fixing a refrigerant leak, replacing a blower motor, or addressing electrical problems. In some cases, if significant components like the compressor or evaporator coil need to be replaced, repairs may take several hours or even a whole day. A professional HVAC technician can diagnose the issue quickly and provide an estimated repair time based on your situation.

Is Air Conditioning Maintenance Necessary?

Yes, AC maintenance is necessary to keep your system running efficiently. Regular maintenance helps prevent major repairs by catching minor issues early, improves energy efficiency, enhances indoor air quality, and extends the lifespan of your unit. Skipping maintenance may not cause immediate failure, but over time, it shortens the life of your system and leads to more frequent repairs. A professional tune-up once a year ensures your AC runs smoothly, keeping your home comfortable all season.

Should I Repair or Replace My Air Conditioner?

It’s best to repair your AC unit if it is less than 10 years old and has been well-maintained. You should replace your unit if it is 10–15 years old, requires frequent repairs, your energy bills have increased significantly, or the repair is very costly. If you’re unsure, a professional HVAC technician at Western can assess your system and provide guidance on the most cost-effective solution for your home.

What should I do if my AC stops working suddenly?

If your AC suddenly stops working,  inspect the circuit breaker to make sure it isn’t tripped. Examine the air filter and replace it if it’s dirty. If you notice ice buildup on your evaporator coils or refrigerant lines, switch the system to “fan only” and let the frozen components thaw before turning it back on. Check the outdoor unit to ensure the condenser isn’t blocked by debris. Inspect the condensate drain line for clogs. If none of these steps restore your AC, it’s time to call a professional technician from Western for a thorough diagnosis and repair.

How Much Does AC Repair Cost?

The AC repair cost varies based on the issue, the type of system, and whether your unit is under warranty. If your system has a manufacturer’s warranty, many parts may be covered, reducing your out-of-pocket cost to labor and service fees. If Western installed your system and it has been properly maintained, your parts and labor may be fully covered under our 10-year warranty. The best way to determine your repair cost is to schedule an inspection so our technicians can diagnose the issue and provide an upfront estimate.