How to Diagnose and Fix Common AC Problems

Published on May 22, 2025 by: alhhvac

Identify Common AC Problems and Learn How ALH Helps Atlanta Homeowners Fix Them

Few things are more frustrating for homeowners than a broken AC unit. When temperatures soar, you need a system that keeps your home cool and energy-efficient. If your unit isn’t working properly, you may find yourself wondering what’s wrong and how to fix it.

This guide covers 11 common AC problems, what causes them, and how to diagnose and resolve each one. We’ll also explain how ALH’s tune up services can help keep your system running at peak performance.

11 Common AC Problems (Broken Down Into Categories)

AC problems come in many forms, but ALH’s expert technicians can handle them all. Here are 11 of the most common AC problems we see—and how we fix them.

Leaks — Including Water and Refrigerants

Even the most reliable AC systems can spring a leak—whether it’s water dripping where it shouldn’t be or refrigerant slowly escaping. Both types of leaks can lead to bigger issues like water damage, mold, and poor cooling performance. Here’s how to spot them and what ALH can do to fix them fast:

• Indoor Water Leaks: Indoor water leaks are one of the most common AC unit problems we encounter. They’re typically caused by a clogged drain line or a disconnected drain pan, which prevents water from properly exiting the system. As a result, water backs up and leaks into your home. ALH staff can fix this issue by clearing the drain line, reconnecting any loose parts, and then inspecting the unit area for mold or water damage.
• Outdoor Water Leaks: Outdoor water leaks—especially around the condenser unit—are a common sign that something’s wrong with your AC system. These leaks often result from a cracked or clogged drain line, low refrigerant levels, or a frozen evaporator coil. Our expert technicians fix the issue by clearing any blockages, resolving drainage problems, and addressing any underlying refrigerant concerns.
• Refrigerant Issues: Refrigerant issues can make it difficult for your system to properly cool and circulate air throughout your home. Leaks in the coils or refrigerant lines often lead to low refrigerant levels, putting extra strain on the compressor. Our trained technicians safely locate and repair the source of the leak, then recharge the system to the correct refrigerant level without exposing you to any harmful chemicals.

Attacks on the Senses: Smelly or Loud Units

Your AC system shouldn’t smell bad or make strange noises. If it does, it’s trying to tell you something’s wrong. From foul odors to sudden screeching or rattling, these sensory red flags often point to mold buildup or mechanical failure. Here’s how we get to the bottom of what your nose or ears are picking up:

• Foul Smells or Odors: Foul odors in your home aren’t just unpleasant—they’re often signs of AC problems. Mold, mildew, and bacteria can build up inside your AC system over time, especially when excess moisture collects in the ducts, drip pan, or evaporator coils. We can identify the cause of any foul odors and then remove the buildup that’s causing them.
• Unusual Noises from the AC Unit: Unusual noises coming from your AC—like banging, rattling, or screeching—are often early signs of air conditioning problems. These sounds can point to loose parts, a worn-out fan motor, or a failing compressor. Don’t deal with these annoying noises without help! Instead, give ALH a call, and our technicians will identify what’s causing these noises and fix them as soon as possible.

Failures of Specific Parts in Your AC Unit

Sometimes, it’s not the whole system that fails—it’s a specific component that starts causing trouble. Whether it’s a dirty coil, a faulty sensor, or a compressor on its last leg, pinpointing these problems early can save you from a costly repair down the line. Here are some of the most common part failures we fix:

• Dirty Coils or Filters: Dirty coils or clogged filters are some of the most common AC problems. When airflow gets restricted, your unit has to work harder, which can lead to higher energy bills and even system failure. We can easily replace dirty filters and coils to improve your system’s efficiency.
• Thermostat Sensor Malfunctions: Faulty thermostat sensors can cause your AC system to cycle too frequently or not at all. This common issue usually happens when the sensor shifts out of place or stops reading the temperature correctly. Our team can reposition or replace malfunctioning sensors to restore full control over your system.
• Damaged or Failing Compressor: Few AC problems are as serious as a damaged or failing compressor, as the compressor is what makes the entire cooling process possible. Electrical issues, low refrigerant, and long-term wear are common causes of compressor issues. In any case, we usually end up replacing damaged compressors to restore cooling and to prevent any further damage.

Full HVAC System Failures

When your entire system stops working, it’s not just uncomfortable—it’s urgent. From a unit that won’t turn on to one that won’t shut off, full system failures usually require fast, expert intervention. Here’s how ALH handles the big issues that bring your AC system to a standstill:

• AC Won’t Turn On: It’s hard to imagine a worse problem than an AC unit that won’t turn on during the middle of a hot summer day. This frustrating problem can stem from a tripped breaker, a faulty thermostat, or even a blown fuse. Whatever the cause, ALH technicians have the electrical training needed to properly diagnose and correct these issues to get your system working again as soon as possible.
• AC Won’t Turn Off: Among common AC problems, a unit that won’t turn off is often overlooked—until it happens to you. This usually points to an issue with the thermostat, relay switch, or control board. By pinpointing the exact cause, our team can make the necessary repairs so you can turn your system on and off as needed.
• Weak or Inconsistent Airflow: Weak or inconsistent airflow usually points to AC fan problems or blockages in the ductwork. A failing fan motor, dirty blower, or clogged air filter can all prevent your system from circulating enough cool air. Our approach to solving this type of issue often means clearing obstructions, cleaning or replacing filters, and making sure the fan assembly is working as it should.

Why AC Tune Ups Are Important

Troubleshooting AC problems can be difficult if you don’t have the right help. However, regular tune ups can keep your system running efficiently and help catch small issues before they turn into expensive repairs. ALH’s expert maintenance services are designed to prevent breakdowns, improve performance, and make diagnosing air conditioning problems easier when something does go wrong.

Without regular AC tune ups, dust buildup, bad parts, or other issues can go unnoticed until your system stops working altogether. A professional AC tune up gives technicians the chance to spot these problems early and before they cause more serious problems. As a result, you avoid experiencing mid-season unit breakdowns and surprise repair bills. Frequent tune ups also extend your unit’s lifespan, helping you avoid having to install a new unit.

How ALH Fixes AC Problems Through Expert Tune Ups

ALH has the experience and technical expertise needed for troubleshooting AC problems. Our team knows how to diagnose air conditioning problems quickly and accurately, whether it’s a faulty thermostat, a failing compressor, or something as simple as a clogged filter. We work with you to understand your system, identify issues quickly, and act decisively.

To make regular maintenance more accessible, we offer a wide array of heating & cooling deals. For instance, we offer a $174/year seasonal maintenance plan that includes two full tune ups annually. New customers can also take advantage of our $49 first-time tune up deal, while our standard $69 rate still delivers comprehensive service. We also offer 10% discounts for seniors and veterans, plus up to $2,000 in rebates for qualifying HVAC system upgrades.

Fix Your AC Problems with Atlanta’s Local Experts

AC problems don’t fix themselves—and waiting too long can turn a small issue into a major repair. At ALH, we help Atlanta homeowners stay ahead of system failures with fast, affordable AC services and expert diagnostics. Whether your AC is leaking, blowing warm air, or not turning on at all, we’ll find the problem and fix it fast.

From affordable new customer tune ups to seasonal maintenance plans and system upgrade rebates, we make it easy to keep your system running strong all year long. Contact us today to schedule your next service or get a free quote from Atlanta’s trusted HVAC professionals.