Air conditioners can leak water for a few reasons. It is possible that the airflow over the indoor evaporator coil is restricted due to either a dirty coil or a dirty air filter. In either case this will cause the evaporator coil to ice up and leak water over the edge of the condensate drain pan.
The most common reason for the air conditioner to leak water is that the condensate drain line becomes clogged, causing the drain pan to overflow. Condensate is simply the water that forms after warm air flows over cold evaporator coils. It’s the same principle that causes beads of water to form on cold glasses of water.
During the warmer months of the year when the air conditioning unit is working hard there is a lot of moisture being pulled out of the air in the home and as this water drips down the evaporator coil and into the drain pan there is algae and other debris that form and run through the drain line.
Eventually, if not maintained, this algae and debris clog the line, forcing the water to overflow the pan or trigger a water detection device (float switch) that is connected to the drain that will shut the air conditioner off before it overflows.
Leaking Air Conditioner Problems & Solutions
There are several reasons why your condensate drain pan or line might be leaking:
1. Frozen Evaporator Coil
Frozen evaporator coils that begin to thaw might leak water on your air filter. Simply open up your AC’s cabinet door to see if you have frozen coils. If you do, make sure the system is off long enough for the coils to completely thaw.
After they are thawed, replace your air filter. A clogged air filter might have been the cause of the frozen evaporator coils in the first place. If you changed the filter and the evaporator coil still continues to freeze, you may have a refrigerant problem or worse. Call your local Phoenix HVAC technician as soon as you can.
2. Cracked Drain Pan
The next thing you want to check is a cracked or damaged drain pan. Simply grab a flashlight and take a look at your drain pan, which is usually located near the floor of your indoor air handling unit. If you know where your evaporator coils are, simply follow a straight line down to where the drain pan is.
With the air conditioner turned off, you can pull out the drain pan and inspect it for debris, cracks, and pinhole leaks. If the crack isn’t clearly visible, clean out the entire pan and wipe it down with some soapy water. If you have a leak, multiple bubbles will begin to form where the leak is.
You can fix small leaks in the drain pan with epoxy glue, but it is recommended that you change the entire drain pan.
Cleaning your drain pan and sealing its leaks will help prevent drain pan overflows and mold spores from developing and spreading. Find out how to replace your drain pan here. If you are having difficulty, your local HVAC technician can do it for you.
3. Clogged Condensate Drain Line
The other cause of a leaking air conditioner is a clogged condensate drain line. Condensate drain lines take the condensate from your evaporator coils and dispose of it outdoors. If you haven’t serviced your air conditioner in a while, or even if you have, your evaporator coils may have become dirty with dust and debris. This is one more reason why you should change your air filter frequently.
As you may be able to guess, if your evaporator coils are dirty and begin to form condensate, the dirt and dust will wash off into the condensate drain pan, which gets transported outside via the drain line. As the dirty, sludgy water makes its way into the drain line, clogs can form, eventually causing an overflowing drain pan.
Some HVAC companies will check and clear your condensate drain line during their annual HVAC inspection, but other times you have to specifically request the service. If you are getting regular HVAC tune-ups, make sure you ask the technician if condensate drain lines are included (Penguin AC maintenance makes this service standard).
If you’d like to clear the drain line yourself, however, there is a way. You just need wet/dry vac and a few other items.
Watch this video to learn how to clear your condensate drain line:
If you don’t own a wet/dry vac then you can buy a Mighty Pump on Amazon for around $80, although we can’t vouch for its effectiveness.
How to prevent clogged condensate drain lines:
A quick way that you can reduce the risk of your condensate drain line from clogging is to locate your drain line and pour a cup of vinegar down the line to kill any mold or mildew that may have started to form in the line.
The best way to make sure you don’t have a leaking air conditioning system or a wet filter is to have your HVAC system maintained on a regular basis. Signing up for a home maintenance plan is probably your best bet. Just make sure that the plan includes regular condensate line inspections and cleanings.
For more information on lowering your air conditioning costs:
- Home Cooling Cheat Sheet
- How to Survive a Phoenix Summer
- Air Conditioning Options for New Home Additions
- Basic Air Conditioning Unit Cleaning Tips
- How to Change An Air Conditioning Filter
- Air Conditioning Repair vs. A/C Replacement: What You Need to Know
- How Replacing Your Air Conditioning Unit Today Can Save Money
At Penguin Air and Plumbing, we want to help make your Phoenix home safe and efficient for years to come