How To Investigate And Repair Central Air Conditioning Drainage Issues

If you have a central air conditioning unit that cools your home, then you most likely have a two part system where the condenser sits outside the home and the evaporator sits inside. As refrigerant moves from the exterior unit to the indoor one, it compresses and pulls heat from the surrounding air. The cool air is then pumped into your house. When this occurs, condensation often builds on the outsides of the coils. The fluid buildup collects in a drip pan and it then drains through an attached drainage line that forces the water to release outside your home. However, if you see water pooling around the bottom of the evaporator, then you have a drainage issue that you need to investigate. Follow the tips below to make sure that water does not damage your home or cause a mold and mildew issue to develop. Check it out.

Check the Drainage Pan

Usually, the drainage pan that sits on the very bottom of your air conditioner evaporator will sit level with the floor or it will be tipped forward so that water flows to the drainage line as it accumulates. However, the pan is sometimes knocked out of place or it tips backward for some reason. When this happens, the back of the pan overfills and releases water that spills on your floor. This means that the water never reaches the drain line, even though it may appear that the drain is actually clogged.

To check the position of the drain pan, remove the access panel on the evaporator. The panel is usually located on the bottom of the unit so that the blower, evaporator coils, the air filter, and the drain pan are all easy to access for maintenance purposes. After the panel is removed, look for a small collection pan that sits underneath the condenser coils. If you see water collecting at the back of the pan, then use a rag to soak up the water. Afterwards, push down on the front of the pan to bend it forward. Most pans are made from aluminum materials, so they will adjust relatively easily. Replace the access panel at this time.

Clean Out the Drain Line

Removing Clogs

If your drain pan looks level or tilted towards the front, then it is likely that your drainage line is clogged. This line contains a dip called a trap that can collect with dust that builds up on the condenser coils. Also, since the motor within the air conditioning evaporator produces some heat, the warmth and the moisture can cause mold to build up and block the drainage line.

To release the clog, try to suck it out of the system. You can do this with a wet and dry vacuum. Look for the drainage line that runs through your basement wall and drains water outside. Bring your vacuum to the exterior side of the drain line and place the hose over the drain opening. Turn on the vacuum and place your hand over the nozzle to create a seal over the drain opening. Look inside your vacuum afterwards to see if a large mass of dirt and mold sits inside.

Clearing the Line

After the clog is removed, you should clean the drain line to get rid of any residual mold. Mold will likely grow again, but it is best to remove as many mold spores as possible from the drainage line so that mold does not grow aggressively within a short period of time. To clean the line, look for a t-shaped access pipe or a small pipe that juts upward from the main drainage line coming out of the evaporator. This pipe is likely to have a small cap on it, so twist the cap to remove it. Pour about one cup of vinegar in the pipe to release the mold and let it sit for an hour or two.

After the vinegar sits for some time, ask a friend of family member to stand outside your house and watch the external drain line. Pour water into the pipe to clear away the vinegar, mold, and debris. Continue flushing the pipe until the water appears clean. Ask your friend to tell you when this happens. 

This process should help to solve your drainage problems. However, if you still see leaking water, call a professional HVAC technician. You may have a leak or other serious issue that needs to be addressed.