Locate the white plastic pipe that leads outside, then check for any blockages like debris or ice. Defrost ice with warm water, not boiling, and use a rod or wire to push through the obstruction. If that doesn't work, call a pro with specialist equipment.
To unclog an AC drain line, turn off the power to the unit. Locate the drain line and use a wet/dry vacuum to suck out the clog. Flush the line with water using a garden hose or cup of water. Check and clean the drain pan under the indoor unit.
Flush Condensate Drain Line
The repair cost to have the drain line flushed runs between $75 to $250.
White vinegar is better for the line. My AC is also in the attic and it's a huge pain. However, it recently became clogged and I now have water damage in my home so I definitely recommend pouring the vinegar once in a while as it will be much worse dealing with the water damage.
It's recommended you use regular distilled white vinegar, as the increased acidity boosts its cleaning properties. If you find the smell of vinegar foul, you can also use peroxide or hot water and a dash of dish soap.
Let Sit for Half an Hour
Once the vinegar has sat for about 30 minutes, flush the pipe with water. If the drain line doesn't flush fully, you can repeat the process until all blockages are removed.
One of the most obvious signs is a puddle of water in your AC's drain pan, which proves the water isn't draining as it should. Other signs include: Standing water near your air conditioner's condenser unit. A moldy smell around the drain or from your system's vents and registers.
professionals suggest that you avoid using harsh chemicals such as Drano to unclog the block.
A clogged condensate drain line will trap water in your air conditioner. As a result, the evaporator coil will eventually turn to ice. The moisture in the drain line can also freeze, which will cause your air conditioner to turn off. But before it does, it'll likely suffer some damage.
Common condensate issues
Common ways to identify if your condensate pipe is blocked are listening for an unusual gurgling sound when the boiler attempts to start, or the boiler may repeatedly 'lock out' or stop working and display an EA code.
You'll soon know if you have a frozen condensate pipe as things will get rather chilly. You're unlikely to have access to heating and hot water. There may also be some rather strange gurgling sounds coming from your boiler. If you take a look at your boiler's control panel, you're likely to find it's stopped operating.
Try pouring hot water down the drain, then follow it with one cup of bicarbonate of soda and a cup of vinegar. Leave it for ten minutes, then chase it with more hot water. A combination of the hot water and the natural cleaner mixture can break blockages up.
Pour One Cup of Bleach Down the Drain Line
It will kill any bacteria or mold present in your drain line, just like vinegar will. Pour one cup of bleach down your drain line every month to help keep it free from clogs. One cup of bleach is the cheapest and easiest way to unclog the drain line in your AC.
All you have to do is pour 1 cup or baking soda down your drain and then follow it with 1 cup of vinegar. After your mixture is in the drain, seal the top of the drain and wait for about an hour so your concoction can start breaking down any clogs. After about an hour, rinse your drain a few times with boiling water.
Dust is one of the most common causes of clogged air conditioner drains. As such, you must clean or replace your AC air filters to prevent dust from building up on the evaporator coils. Do this every few weeks to prevent blockage and keep your AC unit functioning effectively. Flush drain lines.
Leaks with a constant flow rather than slow drip can mean a condensate pipe has become disconnected or punctured. If that's the case, it's important to get your HVAC system serviced as soon as possible to avoid additional problems including further damage to your house.
Take water hose to AH (even if it's on second floor or in attic) and flush the drain so full water pressure is going thru the line (may have to cut drain and glue back together). Clean out internal pan with hose and if it sounds like it's slow or popping, remove male adapter and make sure that's not gunked up.
All right, so in summary, don't use bleach; use vinegar. That helps with any mildew growth—keeps you running clean. It's not going to actually clean your A/C drain, but it can prevent some backups.
Run a plumber's snake into the drain and down the pipe in the direction of its exit. Twist and remove to break through clogs and pull out debris if possible.
Due to its highly acidic nature, apple cider vinegar is self-preserving and doesn't ever really go bad. However, when you buy a bottle at the store, you'll still find an expiration date printed on the label. This is because the FDA requires manufacturers to do so.