Common AC Problems and How to Fix Them Yourself

Published On: February 22, 2025

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Summer is almost here, and the one thing that saves us from the scorching heat is our AC. However, every year, many of us encounter common issues with our air conditioners, such as gas leakage, water dripping indoors, ducting smells, and more.

If you’re facing any of these problems, you’ve landed on the right page. This guide covers the most common AC issues experienced by homeowners in India, along with step-by-step Do-It-Yourself (DIY) solutions. We’ve also included seasonal maintenance tips to keep your AC running smoothly in every weather. Let’s dive right in.

Common Issues in Air Conditioners

Not Cooling the Room

A prevalent complaint among homeowners is that their air conditioner fails to cool the room effectively. This issue can arise from dirty air filters, blocked vents, or low refrigerant levels. When air filters become clogged, airflow is restricted, resulting in diminished cooling performance.

Unusual Noises

Unusual sounds such as grinding, squealing, or banging can indicate mechanical problems within the unit. A grinding noise may suggest worn bearings, while squealing could indicate a failing fan belt. Identifying these noises early is crucial to prevent further damage.

Water Dripping Indoors

Water pooling inside the home is often caused by a clogged condensate drain line or a malfunctioning pump. This issue can lead to water damage if not addressed promptly. Regular maintenance of the drainage system is essential to prevent this problem.

Water Dripping Outdoors

While some condensation outside is normal, excessive dripping may indicate low refrigerant levels or blockages in the drainage system. This issue requires immediate attention to avoid complications.

AC Not Turning On

If the air conditioner fails to start, check the thermostat settings and ensure it is set to “cool.” Additionally, inspect the circuit breaker for any tripped switches. A faulty capacitor or power supply issue may also be responsible for this problem.

Gas Leak

A gas leak from the refrigerant lines can significantly impact cooling performance and pose safety risks. Signs include hissing sounds or a noticeable drop in cooling efficiency. Professional assistance is essential for handling refrigerant leaks safely.

Ducting Smell Problems

Musty or mouldy smells emanating from air ducts often indicate mould and mildew growth within the AC system. Accumulated moisture from condensation creates an ideal environment for these fungi to thrive, leading to unpleasant odours circulating through your home. Clogged drain pans and dirty air filters can exacerbate this issue.

Step-by-Step Troubleshooting Guides

Cleaning Filters

Turn off the AC and unplug it.
Open the front panel to access the air filter.
Remove the filter and clean it with water or a vacuum. Let it dry completely before reinserting.

Fixing Power Supply Issues

Check the main power switch and circuit breakers.
Inspect the thermostat batteries and replace them if needed.
Ensure all wires and connections are secure.

Fixing Ducting Smell Problem

Turn off the AC and inspect the ductwork for visible mould or debris.
Clean the ducts using a vacuum or a specialised duct cleaning brush.
Replace or clean air filters to eliminate odours.
Pour a solution of water and bleach into the drain pan to kill bacteria and prevent mould growth.

How to Check Gas Levels

Evaluate Cooling Performance

Turn on your AC and set it to the lowest temperature.
Observe the cooling output. If the room takes too long to cool or doesn’t cool evenly, it could be a sign of low gas levels

Inspect for Visible Signs

Check the Outdoor Unit: Look for frost buildup on copper pipes or the evaporator coil.
Listen for Unusual Noises: A hissing sound might indicate a refrigerant leak.
Notice Ice Formation: Ice inside or near the unit is another common sign of low refrigerant.

Gather the Tools

Purchase or borrow a refrigerant pressure gauge. Ensure it matches the type of refrigerant your AC uses. Most ACs nowadays come with R-32, which is environmentally friendly.
Get a thermometer to measure air temperatures for further testing.

Access the Refrigerant Line

Switch Off the AC: For safety, turn off the AC and disconnect it from the power source.
Locate the Service Valve: Find the valve on the outdoor unit labelled “Low Pressure” or “Suction Line.”
Attach the Pressure Gauge: Secure the gauge to the valve tightly to get an accurate reading.

Check the Pressure Reading

Turn the AC on and wait for 10–15 minutes to let it stabilise.
Note the pressure reading on the gauge. Compare it to the recommended pressure range mentioned in your AC manual. The range depends on your refrigerant type and ambient temperature.

Call a Professional (If Necessary)

If the pressure is low or you notice a leak, it’s time to call a certified technician.
Handling refrigerants requires specialised equipment and should comply with environmental regulations.

Important Tips:

Do Not DIY Refrigerant Refilling: It’s a technical task best left to professionals.
Regular Maintenance: Prevent gas issues with seasonal servicing and proper cleaning.
Professional Assistance: If you lack the tools or expertise, leave the inspection to experts.

Seasonal Maintenance Tips and Checklists

Pre-Summer Maintenance Tips

Clean or replace air filters, dirty filters can reduce cooling efficiency.
Inspect ductwork for leaks; leaky ducts can cause cool air to escape.
Schedule professional servicing if necessary and ensure the unit is ready for heavy usage.

Post-Summer Maintenance Tips

Turn off the AC’s power supply if not in use.
Clean the outdoor unit and remove debris.
Check for wear and tear to prevent issues next season

FAQs

What is the most common part of failure on an AC unit?

The compressor is the most common part that fails due to wear and tear.

Why would the AC be running but not cooling?

This usually happens due to clogged filters, low refrigerant levels, or dirty coils.

How do you check the AC filter?

Access the front panel, remove the filter, and inspect it for dust and debris.

How do I clean my AC air filter?

Remove the filter, rinse it with water, and let it air dry before reinserting.

Is it OK to clean the AC filter with water?

Yes, but ensure the filter is completely dry before placing it back in the unit.

How to clean an AC compressor?

Turn off the power, remove debris around the compressor, and clean it with a damp cloth.

Is it necessary to get AC serviced every year?

It is not set in stone. However, it is recommended that you get the service done annually as it improves performance and prevents breakdowns.

How do I know if my AC is out of gas?

In India, it’s common for people to blame external factors like air pollution or extreme weather when their AC stops cooling effectively. However, one of the main reasons for poor cooling is low refrigerant (gas) levels.

Since you can’t physically check the gas levels yourself, you’ll have to rely on a service executive’s assessment. Some signs that your AC might be running low on gas include:

Reduced cooling efficiency – The AC takes longer to cool the room or fails to reach the desired temperature.
Hissing or bubbling sounds – This could indicate a refrigerant leak.
Frozen coils – Ice formation on the evaporator coils suggests low gas levels.
Higher electricity bills – The AC has to work harder to maintain cooling, leading to increased energy consumption.

Fortunately, some modern smart ACs now come with built-in gas monitoring, alerting you when refrigerant levels are low. This allows you to schedule a refill before the summer heat becomes unbearable. If your AC isn’t cooling as expected, it’s best to get it checked by a professional.