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  • Writer's pictureVirginia Air

Why Is My Air Conditioner Leaking Water?

Air conditioning leaks can be frustrating, messy and potentially cause significant water damage to your system or home which could be costly if not taken care of. We receive calls from customers asking why they have leaking water so we hope that this blog can shed some light on these causes.

HVAC System Water Leak Causes Usually Fall Into 3 Categories:

Clogged Drain Line/ Condensate Pump Failure

A clogged condensate drain pipe can back up into your AC system’s condensate drain pan and overflow water in through your furnace or air handler and onto the floor or ceiling below. This is probably the most frequent cause of water leakage from a central AC system and service calls to HVAC professionals as summer temperatures and humidity rise. Condensate drain lines can become clogged with airborne pollutants, rust, algae and other debris. A malfunctioning or dirty condensate pump can also cause water leakage from your AC system, flooding your attic or basement. Due to the continual presence of water, mold and mildew can grow inside the unit causing it to clog. Not to mention what the water does to your HVAC system’s metal parts including your condensate pan.

HVAC System Icing or Freezing Up

Did you know that your AC cools your home by removing the heat? When your system “freezes up”, it is a reaction to a restriction like reduced or blocked air flow, a part failure or refrigerant problem. Where the ac freezing occurs is usually your indoor coil that is not visible since your indoor coil is encased for proper airflow through and around it. The ice can form larger than the coil and as it starts to melt, the ice can block the condensate pan from draining or misses the pan all together and leaks water through your system. When we do see ice, it has usually formed at the source of a refrigerant leak or on an uninsulated refrigerant line or when the coil is a block of ice and now icing down the refrigerant lines. When your AC is not keeping temperature, lack of air blowing from registers or water on the floor is usually an indication of an iced up system.

A Breach or Break In Your Condensation System

This third cause would be a breach or break of your condensation pan or drain. Contrary to belief, your condensate pan is not made to hold water. Rather it is better described as a gutter or tray designed to catch the falling water off your indoor coil and pitched to a drain line to drain away. A breach or a break is not something that we run into but maybe a few times a season. We find that a plastic condensate pan has been subjected to higher than normal temperatures becoming brittle or a metal pan is holding or held water previously and has rusted through.

Once in a while, we find that an inexperienced person has attempted to clear a stoppage and broken the drain line even causing the fragile condensate pan to crack. This can be a very costly lesson as obtaining a condensate pan and attempting to install it at the perfect pitch outside of the factory is not a good scenario. Some manufacturers will not sell just the condensate pan and it becomes the cost of replacing the indoor coil or air handler in some cases. So Please Do Not Attempt To Clear Your Condensate Drain If You Have Not Been Shown How!!

What Is The Number One Cause We Find All Three Of These Water Leak Issues Share?

Yes, you guessed it! Dirty Air Filters and/or Dirty HVAC System(s)! Why is an air filter so important you ask? Your system needs to bring in air from your home to heat or cool it. That means any debris in the air like oils, cooked food, smoke, burning candles or wood fireplaces, lint, dust and everyday pollution from just going in and out of your home will potentially cycle through your HVAC. The filter is there to catch as much debris and dust to prevent build up on things like your coils, burners, heat exchanger, electric heaters and blower motors. That same air flow also cools down your system’s motors and parts. Obviously, filters cannot block all debris or it would block air flow so maintenance and flushing your condensate drain is still needed to prevent build up.

A dirty filter restricts air flow which raises the system’s interior temperatures resulting in burnt out/shorted motors and cracked pans, prevents your refrigerant from cycling properly causing the system to freeze up/build pressure causing refrigerant leaks, clogged condensate drains, condensing ductwork, mold/mildew growth and water damage. Not to mention that your system will get air from wherever it can, in some cases, bypassing your air filter so you are then cycling that same debris and dust right through your system you were trying to prevent in the first place! If that isn’t enough to show you the repair dollar signs adding up, how about the loss of efficiency from your system, your system’s inability to keep consistent temperature and the rising cost of your utility bills to boot? So who is in for changing their air filter monthly and having their system checked and cleaned every fall and spring??

Ways to Avoid HVAC Water Leakages

There are several things that can be done to help prevent water leaks:

  • Change your 1” thick air filter(s) or clean your electronic air cleaner’s pre- filters MONTHLY.

  • Schedule spring and fall system maintenance to maximize performance and minimize furnace and AC repairs especially if your system has been subjected to water or refrigerant leak(s).

  • Install a water alarm wired to shut your HVAC system off when water is present.

  • Make sure your ductwork is properly insulated.

  • Invest in a clear condensate trap with wired-in float to shut system off when clogged.

Once you notice what appears to be water leaking from your AC system, shut your HVAC system off and phone your HVAC technician immediately to avoid any further damage.


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