Why Isn’t My AC Working? 10 Common Reasons & Easy Troubleshooting Solutions

Nothing’s worse than a broken AC during a heat wave. If your AC is not working, Central Oregon Heating, Cooling, Plumbing & Electrical can help. 

In most cases, a malfunctioning AC is caused by one of the following 10 issues. While some of these problems require professional help, some of them can be fixed by the homeowner. Read on to learn which AC troubleshooting tips can be used for your current issues.

Quick Troubleshooting Checklist 

Our heating, ventilation, and air conditioning (HVAC) technicians have experienced all types of AC issues over the years. Before reaching out for our top-rated AC services, you can use the following checklist to troubleshoot the problem. If the following tips don’t work, give our team a call for professional support.

Step-by-Step Checklist

• Check power systems, such as your breakers and switches, to make sure they are flipped on and fully functional. 
• Ensure the thermostat is set correctly. It should be turned on to the cooling mode and set to the correct temperature. 
• Inspect your filter and vents. Clean or replace your filters if they are dirty. You should also clean and open the vents.
• Look at the outdoor unit for obstructions. From time to time, you should clean the condenser coils.
• Listen for unusual sounds that may indicate the source of the problem.

10 Common AC Problems & How To Troubleshoot Them 

Even with the best care, an air conditioning unit can eventually break down. When that happens, you can use the following 10 AC troubleshooting tips to fix the problem.

1. No Power / AC Won’t Turn On

When an AC doesn’t turn on, the underlying problem may be connected to a tripped breaker, switched-off disconnect, or blown fuse. Start troubleshooting by making sure the disconnect switch is in the on position. Then, check your breaker or fuse panel. As needed, you should reset tripped breakers and replace blown fuses.

For your safety and the safety of your home, don’t repeatedly reset tripped breakers or fix blown fuses. If these problems keep happening, it’s because of an ongoing electrical malfunction that should be professionally repaired.

2. Thermostat Issues

When you have an AC that won’t work, check out your thermostat. Often, the thermostat is set to the wrong mode. Try changing it to the “cool” mode. Adjust the target temperature to see if the AC switches on.

If these tips don’t work, try replacing the batteries in your thermostat. You may also need to have the thermostat recalibrated or replaced.

3. Dirty or Clogged Filters

Dirty, clogged filters can restrict airflow and overload your HVAC system. You should always make sure to replace your filters every one to three months. If you have pets or a lot of dust, you should clean or replace them more frequently.

4. Frozen Evaporator Coils

Frozen evaporator coils can occur if you have low refrigerant levels or poor airflow. When these issues happen, the evaporator coils end up freezing up. To deal with this problem, you first need to let all of the ice thaw completely. Then, try replacing your air filter. 

As long as the clean filter solves the problem, you can continue using your AC like normal. If it doesn’t, you need to call an HVAC technician for help.

5. Low Refrigerant or Refrigerant Leaks

If you’re struggling with an AC not working, the issue may be related to your refrigerant levels. When the refrigerant levels are low, your AC transfers less heat. Low refrigerant levels happen due to leaks, which are often caused by corroded lines or bad fittings. 

Anytime you’re dealing with refrigerant, it isn’t a DIY problem. You need to call a certified technician to locate and repair the leaks. Once this is done, the technician can recharge your AC.

6. Dirty Evaporator or Condenser Coils

Over time, debris and grime can get onto your evaporator and condenser coils. In turn, this can reduce the heat exchange efficiency of your system. To repair the problem, you should carefully clean your coils or schedule a professional HVAC cleaning appointment.

7. Blocked or Obstructed Condenser Unit

If plants, tarps, or debris are blocking airflow to your condenser unit, it can reduce your AC’s efficiency and performance. This problem is easily remedied by cleaning around your unit. Then, make sure it is powered off before you rinse it gently with a hose from the inside out.

8. Faulty Capacitor or Blower Motor

A worn-out capacitor will struggle to start your compressor. In a similar fashion, a blower motor failure can prevent air from flowing through your AC. For both of these issues, you can’t troubleshoot on your own. You need to schedule a professional AC repair appointment to get the worn parts replaced.

9. Strange Noises or Smells

If you hear a rattling noise, it may be due to loose parts that need to be tightened. While buzzing noises are electrical in nature, musty smells are typically due to mold and drainage issues. Mold remediation and cleaning the condensate drain line can remedy musty odors. For buzzing noises, you need a professional to handle the electrical repairs.

10. Leaking Water / Condensate Issues

If your AC is leaking water, it may be due to a clogged condensate drain line. Additionally, poorly insulated ducts can also cause condensation to happen. 

To fix this issue, start by cleaning the drain line with a vinegar flush. Then, make sure your ducts are insulated. If everything is draining properly and you still have a leak, schedule an HVAC inspection.

When To Stop DIY & Call Central Oregon Heating, Cooling, Plumbing & Electrical

While AC troubleshooting tips can help with simple problems, you should call a professional in the following circumstances. When it comes to safety and long-term AC replacement costs, scheduling an early intervention is key.

• Refrigerant leaks
• Electrical or capacitor issues
• Compressor failure
• Frozen coils that don’t thaw
• Persistent strange noises, musty smells, or weird odors

FAQs 

Over the years, we’ve found that residents in Bend, Madras, and Redmond tend to have a few common questions on what to do when an AC unit is not working. 

My AC won’t turn on, should I reset the breaker?

If there is a sudden power surge or a tripped breaker, it can cut the power to your air conditioner. One way to check for this issue is by resetting the breaker right away. 

However, you need to call one of our HVAC technicians for AC repairs right away if it trips again. A frequently tripped breaker indicates an underlying electrical problem that needs to be resolved by a professional. ACs can trip the breaker if a clogged air filter or dirty coils cause the AC to overheat. Similarly, loose wiring, capacitor problems, and dirty condenser coils can also lead to a tripped breaker.

Most central air conditioners use a double-pole breaker in the electrical panel. In some cases, the indoor air handler may also have a separate breaker. If only one breaker trips, the AC may still run but only blow warm air. When resetting the breaker, you should remember to reset both breakers.

How often should I replace my air filter?

You should ideally replace your air filter every one to three months. When the air filter becomes clogged or dirty, the AC has to work harder to pull air through the filter. Because of this, you may experience higher energy bills than normal. Dirty filters can also result in costly repairs and the eventual breakdown of your air conditioning unit.

Some homes should consider replacing their air filters more frequently. Consider more frequent replacements if: 

• There has been significant wildfire smoke in the area.
• You have pets in your home.
• Someone in your household smokes.
• You have high dust levels.
• The AC manufacturer specifically stated that the filter should be replaced more frequently.
• You’re using your AC more frequently than normal.
• Someone in your home suffers from allergies or asthma.

Why does my AC freeze up?

An AC that is not working and freezing up all the time stems from two main problems. The HVAC system’s airflow may be restricted, or your AC has low refrigerant. However, multiple problems can cause these situations. 

Refrigerant lines are part of a closed system, so you can only develop low refrigerant if there is a leak. With the help of our HVAC experts, you can get your refrigerant lines tested, repaired, and recharged.

Airflow issues can be due to a clogged air filter, dirty evaporator coils, a broken blower fan, blocked vents, or ductwork-related issues. Because of this, it’s a good idea to reach out for a professional diagnosis. 

When your AC freezes, you should first let it thaw completely. In severe cases, this can take up to a day. Then, clean or replace your air filter. If that doesn’t work, call a professional for help.

Can I clean the condenser coils myself?

If you’re experiencing decreased cooling performance, longer cycles, or more expensive energy bills, it may be time to clean your condenser coils. You can carry out this maintenance task on your own. If you need deep cleaning or fin straightening, you should always call a professional.

To clean your condenser coils, start by powering off the AC unit. Then, you can remove the outer cover and vacuum any debris out of the inside of the unit. You can use a mild detergent and a soft brush to clean off debris, but you should be cautious about damaging the fins. They are sharp, so exercise caution to avoid cutting yourself.

Then, you can use a low-pressure hose to rinse the unit from the inside out. Make sure all of the soap and debris are removed. Once you are done, you can reassemble the AC and turn it back on.

What does a hissing noise mean?

A hissing noise is an indication that you should reach out for a professional inspection and AC maintenance right away. This type of noise typically occurs because of high pressure or a refrigerant leak. You can also hear hissing if there is a leak in your ductwork.

When it comes to AC troubleshooting tips, none of these problems are things that you can handle on your own. Under federal law, there are strict requirements about who can recharge refrigerants because of the health, safety, and environmental concerns involved. Similarly, diagnosing pressure issues and duct leaks requires high-tech tools and professional expertise.  

What’s the first thing to check when an AC stops working? 

If an AC is not working, the first thing you should do is check your thermostat. Sometimes, a household member will turn the AC off and not mention it to anyone else. Besides checking the temperature, you should make sure your AC is set to the cooling mode. 

To troubleshoot other common problems, you should also check the breaker and air filter. You can reset the breaker if it was tripped. Similarly, you should clean or replace dirty air filters. 

If none of these steps work, you should call one of our HVAC technicians for help. Pay attention to all of the symptoms your AC is experiencing because this will give us a better idea about the problem.

How do you reset an AC unit?

While there are many differences between various air conditioning units, the manual process for resetting the AC is generally the same. To reset your unit, turn your thermostat to the off position. Then, you should switch the AC’s breaker to the off position as well. Many central air conditioners have two breakers, so remember to turn off all of the AC’s breakers.

Afterward, you should wait about five minutes. This gives the internal pressure time to equalize and lets the AC’s control board reset. After five minutes, you can switch the breakers on and turn on the AC. 

Get Professional AC Repairs Today

Need reliable AC repair fast? Contact Central Oregon Heating, Cooling, Plumbing & Electrical today for same-day service, expert diagnostics, and efficient repairs. Whether it’s low refrigerant, electrical issues, or routine maintenance, we’ve got your comfort covered. If basic AC troubleshooting tips won’t help, you need to bring in the HVAC experts.

Schedule online now for professional AC repair services or call us to restore your cool quickly!