Learn How to Clear Your Air Conditioning Condensate Drain Clogs

air coil

The evaporator coil is located within the indoor air handler or indoor AC unit components that work with your heat pump or air conditioning system. This HVAC part pulls heating from the air in order to cool your home. During the cooling process, the indoor air receives some dehumidification and water vapor converts into condensate. The air conditioner is outfitted with a drain pan and AC condensate drain line to drain water out of the HVAC system and away from the house, as long as there are no condensate drain clogs.

A clogged AC drain line could cause damage to your home as well as your HVAC equipment. A clog within the condensate drain line may result in water damage to the indoor areas of the house located near the air handler or furnace sit, as well as the unit itself. Standing water in the condensate pan will affect the air conditioning process, forcing the system to operate less efficiently and struggle to cool your living areas. When the inside of the indoor air conditioning unit is wet, mold can grow within and harm the HVAC system as well as cause indoor air quality issues for your family.

When your air conditioner drain line is clogged, the clog needs to be removed right away to prevent damage and keep your air conditioning unit running efficiently. Williams Comfort Air shares how to clear a clogged AC drain line with tools you have at home. If you are unable to remove a clog from the condensate line, call us for professional AC drain line repairs and HVAC service.

What Causes a Clogged Condensate Drain Line?

To understand how a condensate line can become clogged, it helps to know how the cooling process works. Indoor air flows from living areas through a return vent near or within the room in order to travel back to the air conditioner when more cooling is needed. The indoor environment can be very polluted, so this air often brings along debris like pollen, dust, and other particles.

As air passes over the evaporator coil for cooling, the debris can settle on the coil and in the condensate pan that sits below it. When air is cooled, the coil becomes wet with condensate. This water eventually drips into the pan, carrying debris along with it.

As water drains out through the condensate drain pan and pipe to the outdoors or to a floor drain located near the unit, the particles stick within. Eventually a clog can form from accumulated matter. Pollutants and the wet environment can feed mold growth inside the HVAC system, and cause algae to develop in the pan – these materials can also contribute to a clog in the drain line.

Signs Your Drain Line Is Clogged

If your home’s AC drain line has a clog, you’ll find out soon after the system reaches this point. A clogged AC drain line produces signs including:

  • Wet surfaces surrounding or near the indoor unit
  • Water damage to areas located by the HVAC equipment
  • Standing water in the condensate pan
  • The odor of mold or musty smells coming from vent registers
  • The air conditioner or heat pump doesn’t keep the home cool enough
  • The AC unit doesn’t turn on

That’s right, a clog in the condensate drain system can prevent your air conditioner or heat pump from turning on altogether! Some units have a float switch within the drain pan, which rises as water accumulates. Once it hits a certain point, the switch tells the air conditioner not to turn on even when the thermostat instructs it to run a cooling cycle – further cooling cycles would add more water and the pan would overflow, causing water damage to your home and HVAC equipment.

How to Fix a Clogged Condensate Drain Line

A clog can form either in the drain pan below the indoor coil or along the AC condensate drain pipe that runs between the indoor HVAC unit and a nearby drain or the home’s exterior. Before you call for HVAC service, follow these tips to remove clogs from your AC drain line without the wait or expense of professional help.

  1. Turn off power to the air conditioning unit or air handler.
  2. Remove the panel on the air handler or indoor unit to access the evaporator coil – for air handlers, the cooling coil is typically found on the side where air enters the unit; for furnaces, the coil is usually located on the outgoing side.
  3. Remove any standing water from the drain pan. Soak up water with rags or use a wet dry vac shop vacuum to suction out the condensation.
  4. Clean the pan with a mild soap or vinegar to remove dust, dirt, mold, algae, and other pollutants. Cleaning also helps prevent future mold, mildew, and algae growth in the pan. Pan tablets can be added to help keep the pan clean.
  5. Insert a thin, wire cleaning brush into the drain hole from the pan to dislodge debris that could be clogging the AC drain line at this access point.
  6. Find the vent tee, which is a fitting along the pipe connecting the pan to the drain line. Remove the PVC cap and insert the wire brush to clean matter and clogs from this access point. The following methods can be used to remove clogs close to this end of the drain line.
    1. Attach a wet dry vacuum hose to the T-shaped pipe and create a seal with tape. Let the vacuum run for a few minutes to suction out clogs.
    2. Insert a plumber’s snake down through the vent tee into the drain line and remove to draw out clog matter.
    3. Insert a garden hose down into the vent pipe and into the drain line (make sure the hose does not run back toward the drain pan). Turn on the water and allow it to flow through the drain line and out to the floor drain or the home’s exterior, which can flush out a clog in the pipe.
  7. Find the end of the AC condensate drain line that empties water from the system outside or into a floor drain near the HVAC system. From this access point, there are a few different methods that can be used clear a clogged AC drain line.
    1. Insert a wire cleaning brush into the opening to clean out debris that have formed a clog at the end of the drain line.
    2. Thread a plumber’s snake into the pipe to bust through a clog and pull the remaining matter out of the line.
    3. Fit the hose of your wet dry vacuum or shop vac over the exit point of the drain line. Form a seal by attaching the vacuum hose to the drain line with tape. Turn on the wet dry vacuum or shop vacuum and let it run for several minutes in attempts to suction out the clog.
    4. Place a garden hose at the exit of the drain line and hold with your hand to form a connection. Turn on the hose in short bursts lasting only a few seconds each. These short blasts can force water through the clog and break it up so it flushes out of the drain line once the hose is removed.
  8. Clean the drain line. Pour a cup of distilled vinegar into the drain line at the vent tee access point inside the house. The vinegar kills any mold, algae, and bacteria sitting in the condensate drain and prevents regrowth. Allow the vinegar to sit in the drain line for an hour or more.
  9. Pour a cup of water down the vent tee access point through the drain line. Have a helper watch the drain line exit to see if the water freely flows through the drain and drains from the exit point, which tells you that you were able to unclog the AC condensate drain successfully.
  10. Replace the PVC cap on the vent tee, replace the panel on your furnace or air handler, and restore power to the air conditioner.

If you are unable to unclog your air conditioner condensate drain following the above instructions or are not comfortable performing these steps on your own, call your trusted HVAC company for air conditioning repair service. A professional technician is able to remove clogs and assess your system to determine what caused the clogged AC drain line.

Air Conditioner Maintenance Keeps Condensate Lines Clog-Free

Regular maintenance is essential to the ongoing performance of any air conditioner, air handler, heat pump, or other cooling unit. Professional maintenance tune ups should be performed each year, and this service addresses the system’s condensate drain line and drip pan as well as other vital air conditioning system components. Any clogs will be removed during maintenance so your air conditioner functions as expected during cooling season.

Protect your air conditioner and your home by caring for the AC condensate drain. Call Williams Comfort Air to schedule an AC maintenance tune up to prevent clogs or request repair service to remove condensate drain line clogs affecting your system now.

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