How to Fix a Leaking AC Unit

How to Fix a Leaking AC Unit: Step-By-Step Guide

How to Fix a Leaking AC Unit: A Step-By-Step Guide

In the mid-west, especially in the summer, the last thing you want is a leaking air conditioning unit. But, do not worry yourself too much. There are steps that you can take to help fix the problem, or at least slow it down until a professional can arrive to fix the leak. Here are the three main causes of leaking air conditioning units and the steps to fix them:

1. Cracked Drain Pan

    • Turn off Air Conditioning Unit
    • Use Wet-Dry Vacuum to Clean the Drain Pan
    • Temporarily Seal Crack with Water Sealant
    • Replace Pan (If Cracked or Missing)


2. Clogged Drain Line

    • Locate the PVC Pipe Near Air Handler’s Drain Pan
    • Unscrew the Cap and Pour About 6 Ounces of Vinegar Down the Drain
    • Locate Outdoor Condensate Drain Line
    • Connect Wet-Dry Vacuum and Turn Onproduct pricing3. Clogged Air Filter


Fixing a Leaking AC Unit In-Depth

1) Fixing AC Leaks Caused By A Cracked Drain Pan

If you have noticed that your air condition unit’s drain pan is either cracked or overflowing, there are a few steps to take to solve this problem, without the need of a professional. Just remember, your air conditioning unit’s drain pan is located underneath your indoor air handler, and it catches any condensation from your air conditioning unit.

The indoor air handler is where your evaporator coils are located. After turning off your air conditioning unit, insect your drain pan and piping for leaks. The pipe is usually connected to your drip pan and discharges the condensate outside.

After checking for leaks, use a wet and dry vacuum to clean the overflow pan and inspect the bottom, corners, and edges with a flashlight.

The flashlight will show you where light is getting through, and exposes the crack. Cracks can be temporarily fixed with a water sealant that you will need to spread over the crack.

ac water sealant

product pricing

However, this is not a permanent fix. You will need to go to a home improvement store, or order online, and purchase a new drain pan for your air conditioning unit.

Typically, there are two drain pans, one located just underneath your evaporator coils that is permanently attached, and the other is underneath the unit and is removable. The drain pan located underneath your air conditioning unit is a part that you can replace yourself.

However, if you find a crack in the drain pan that is permanently attached, still follow the steps above, but you will have to call a professional to replace this pan as they are welded to the air conditioning unit.

How to Fix a Leaking AC Unit

2) Fixing AC Leaks Caused By A Clogged Drain Line

If the drain pan was not the cause of your air condition unit leak, then another common culprit is the drain line. If so, this can be a do it yourself project, if you have the needed equipment.

Typically, the drain line gets clogged from fungi, algae or debris buildup. To keep the drain line from getting clogged, you should regularly clear the lines.

When your drain line is clogged, the steps to fix it are simple. First, you will need to locate the PVC (Polyvinyl Chloride) pipe near your air handler’s drain pan. It should have a piece of pipe sticking up at a 90-degree angle, with a little cap on top.

Next, you will need to unscrew this cap and pour about six ounces of vinegar down the drain line. Doing this every few months will kill any algae or fungi that have developed in your drain line.

If your drain line is still clogged, there is one more step you can do before calling in the professionals. If you choose to take it on by yourself, you are going to need a wet and dry vacuum.

To clear the pipes yourself, you will need to locate your outdoor condensate drain line, near your condenser unit. Once you have found it, connect your wet and dry vacuum, and turn it on. Most home improvement stores sell wet and dry vacuum attachments that connect your outdoor drain to your wet and dry vacuum.

The suction from your wet and dry vacuum should pull out any of the remaining debris that is clogging your drain pipe. If after connecting your wet and dry vacuum, the problem continues, you will need to call in the professionals.

3) Fixing AC Leaks Caused By A Clogged Air Filter

A clogged air filter is typically the main cause of an air conditioner unit springing a leak. When an air filter gets dirty, air cannot pass through as easily as it needs to, which causes the evaporator coils to freeze up.

Since the evaporator coils have refrigerant that flows through them and need proper airflow, they form ice and will start to drip water. Frozen evaporator coils can also be caused by dirty coils, blocked vents or registers, a broken blower motor, or a lack of refrigerant.

When your evaporator coils freeze over, this means that your refrigerant can no longer take in the heat on your property, which leads to a lack of cool airflow, or even a lack of airflow altogether.

When this happens, it puts your compressor in a potentially harmful situation. If you notice your evaporator coils have frozen over, turn off your air condition unit immediately and do not power it back up again until all the needed repairs have been done. Otherwise, you may be facing a much larger repair or replacement bill.How to Fix a Leaking AC Unit

This situation can be avoided though; all you need to do is replace your air filter every 30 to 90 days.

When you purchase an air filter, the labeling on the package will tell you when to replace the filter. Every style filter is different, so keep that in mind. Also, filters will need to be replaced more often in the summer, as the air conditioning unit will be running more regularly, as well as for an extended period of time.

As a reminder, use the calendar app on your smartphone or even write it down in a place you view often, to check your air filter at the beginning or end of every month.

Another way you can keep this problem from occurring is by avoiding covering any vents or registers. Doing these steps should fix your frozen evaporator coil/clogged air filter problem.

However, if it does not fix the issue, continue to leave your air conditioning unit off and pick up the phone. Typically, if replacing the filters and unblocking the vents and registers does not work, that means that you probably have a low refrigerant charge. A low refrigerant charge is a problem that only a professional HVAC worker can fix.

Summing it Up

Typically, there are three main reasons that your air conditioning unit will start to leak. Those reasons are a cracked or missing drain pan, a clogged drain line or a clogged air filter.

If you notice that your air conditioning unit has sprung a leak, first thing to do is to turn the unit off completely. Then, you will need to look for where the leak is coming from. Normally, you will need a wet and dry vacuum to fix any of these problems yourself, unless you just need to replace your air filter.

Once you have discovered where the leak is coming from, you will either need to patch and replace the faulty piece of equipment, or you will have to clear the clog with some vinegar and suction from the wet and dry vacuum. If doing either of those did not fix the leak, then you will need to call a heat, venting and air conditioning professional.

If your leak is not coming from any of the items listed above, like from under the floor, inside the walls or in the ceiling, shut off your water and call a hvac professional immediately.

This means you have a busted pipe in an area that you cannot get to. In addition to a heat, venting and air conditioning specialist, you will most likely need to call a construction, drywall, or flooring specialist to repair the damages.

An air conditioning unit is a piece of machinery. And just as a car needs a tune-up, your air condition unit needs regular maintenance to keep issues, like the items listed above, from happening.

If you are not sure about how best to maintain your air condition unit, you can always discuss a plan with a heat, venting and air conditioning specialist or even hire them to conduct regular maintenance on your machine.

We as a society have become very accustomed to our heating, ventilation, and air conditioning lifestyle. When one of them goes out, we tend to stress out and worry. Luckily, there are steps that all homeowners can take to keep their systems running smoothly. Just take a deep breath, break out your work gloves and get cranking.

Matt McWilliams

Hi there! My name is Matt and I write for Expert Home Report. I enjoy writing about everything related to home improvement, home tips and DIY. In my spare time, I'm either spending time with my family, doing a DIY project or learning a new skill.