How to clean condensate pump drain line

How to Clean Out the Condensate Drain Line on Your Central Air Conditioning System

02/07/17

During the chill of winter, the last thing you are probably thinking of is your home’s central air conditioning system. However, this season is the best time to perform maintenance tasks that will tune your system and prevent trouble from happening when you flip on the switch in the summer.

One maintenance task that you should not neglect is clearing out the condensate drain line. A failure to keep this line clean can lead to clogs that will shut down your unit or cause water damage when condensate overflows. Below is how you can perform this easy but vital task:

Locate the Condensate Drain Pipe Opening

Finding your condensate drain shouldn’t be too difficult, especially if you live in a humid climate where air conditioners pull a lot of moisture from the air. During the summer, there are literally gallons of water that pour from the typical condensate drain, and this water makes finding the drain location easy.

Of course, if you are searching for the drain in the dead of winter and haven’t been around during the summer to see the drain produce water, it may take a little while to find the pipe opening. If you don’t know where to look, search for a short section of ¾-inch PVC pipe exiting a wall or your home’s eaves.

Locate Where the Drain Pipe Leaves the Evaporator

After finding the drain opening, the next step is to head to the opposite end of the pipe and find where it attaches to the evaporator coil. As the water flows from the coil, it is collected in a pan and funneled into the drain pipe; as the pipe exits the evaporator, it will curve downward to form a trap. The pipe will also contain a drain cleanout at the top of the section just before the trap.

Open the Cleanout to Access the Drain Pipe

The cleanout is simply an access point for adding chemicals or performing other maintenance inside the drain pipe. It is usually sealed, but there are occasions when the opening isn’t capped. If the pipe is sealed, remove the slip cap that covers the cleanout and set it aside in a safe location.

Take a moment to peak into the opening with a flashlight and you may see green slime, mold, and other unpleasant substances. These are what you are trying to remove from the drain line.

Pour a Cleaning Agent into the Cleanout

Once the cleanout is open, the next step is to flush it with an antifungal, antibacterial, and antiviral cleaning solution. Ordinary, unscented laundry bleach meets these qualifications and is also inexpensive.

To add the cleaning solution, take a funnel and slip it into the cleanout opening. While holding the funnel steady, carefully pour two quarts of laundry bleach into the funnel and allow it to find its way into the drain line. If the bleach begins gurgling or doesn’t drain quickly, then pause and wait for a few seconds. Continue pouring bleach into the funnel until the original two quarts is all but gone.

Rinse Out the Condensate Drain Pipe

After pouring bleach into the condensate drain through the cleanout, allow the cleaning solution to remain inside the pipe for several minutes to permit the bleach to work against the slime and mold. Most of the bleach will probably drain out of the pipe on its own, but you will still need to rinse out any remaining bleach to prevent possible damage to the inside of the PVC pipe.

To rinse the drain, pour approximately one gallon of warm water into the funnel and allow it to flow through the pipe, flushing out all the bleach and debris. Once the water runs clear, you can feel confident the drain pipe is squeaky clean and ready for summer.

Obtain Help if You Need It

If you aren’t comfortable performing this procedure on your central air conditioning system, then contact a qualified HVAC professional to help. They will be able to not only clean the condensate drain but also perform other critical maintenance necessary to keep your unit running in tip-top condition.

Posted in: Air Conditioning

Water gushing down your ceiling is not a sight any homeowner wants to come home to, yet it is all too common when air conditioning system drain lines get clogged and overflow. Because the weather in Houston is both hot and humid, it is very easy for these condensate drain lines to collect a slimy mixture of dust, mold, and algae. Yuck! Luckily, there are several ways you can keep your air conditioner’s drain line clear. If you can measure out liquid and pour it in a pipe, you have the necessary skills to keep your drain line unclogged year round.

What chemical should I pour down the condensate drain?

We recommend at least four times a year to pour a one-fourth to one-half cup of plain, white vinegar in your condensate drain. Don’t use bleach as it can spill onto your metal drain pan and react with the metal, causing problems later on. Vinegar is acidic but does not react with copper, zinc, or aluminum so there is no risk of spilling or accidentally harming other metal pipes and equipment nearby.

Where is the drain line located?

For many homes in the Gulf Coast, the central air conditioner’s evaporator coil and furnace are located in the attic. The evaporator coil is encased in a box with a drain sitting underneath and hoses surrounding it. You’ll want to look for 3/4″ PVC pipe that is open to the air. This is where you want to pour that vinegar.

How else can I protect my ceiling/wall from leaks?

If you do not already have one, your HVAC contractor can install a “ceiling saver” or “float switch.”  These handy devices turn off the air conditioning unit if the drain pan fills up, which only  happens when the drain line is stopped up. This will keep your air conditioner from pumping out more water into the pan, eliminating costly spills and sheetrock to be replaced.

Can UV lights in the evaporator coil reduce the slime?

Yes. Another tactic we recommend is installing an Ultraviolet Light in the evaporator coil. Not only does this improve air quality in the home, it reduces the grime that can develop on the evaporator coil and slime that can accumulate in the condensate drain line, too. Because our climate is so humid, the air conditioning equipment parts that take out humidity from the air are constantly wet and that is a recipe for a build up of dust, mold, and algae. By the way, Terry’s A/C and Heating periodically runs specials in the summer on installing UV lights.

What do I do if I see my drain pan full of water?

Good news. You’ve caught the problem early and can call your HVAC contractor for help. A reputable contractor will blow out the line and do a thorough check to make sure that the problem isn’t coming back. By keeping your line maintained with regular doses of vinegar, once each season, this problem should be less common.

We Can Help

If you are in need of expert advice on maintaining and repairing your air conditioning system, contact the cooling experts at Terry’s A/C and Heating at 281-495-7830 and see our service area. We’ve seen all sorts of condensate drain issues from misdiagnosed plumbing problems to critters in the attic chewing through drain lines to get to the water, we can help keep your HVAC system running when the heat is on. Find out how we are different from other contractors in West Houston and give us a call today!

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