I've blown out the A/C drain line several times with the hose the past few days and it keeps filling up after a days worth of using the A/C. Water flows out of the end of the pipe on the outside of the house when I blast it out, but it keeps getting clogged. Any ideas on what I should do?

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Originally Posted by ian_land

I've blown out the A/C drain line several times with the hose the past few days and it keeps filling up after a days worth of using the A/C. Water flows out of the end of the pipe on the outside of the house when I blast it out, but it keeps getting clogged. Any ideas on what I should do?

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What are you blasting it with? Garden hose, or pressure side of a vacuum cleaner? Sometimes items like little animals(MIce) Can climb into the pipe from outside and get stuck then die. You might just be moving the obstruction back and forth. If you have an electricians fish tape or something similar you can feed it down the pipe till it comes out the other end outside. This way there should be no obstructions in the pipe. I always use C02 or nitrogen pressure to blow drains but that is something a home owner probably does not have.

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Originally Posted by hvac1000

What are you blasting it with? Garden hose, or pressure side of a vacuum cleaner? Sometimes items like little animals(MIce) Can climb into the pipe from outside and get stuck then die. You might just be moving the obstruction back and forth. If you have an electricians fish tape or something similar you can feed it down the pipe till it comes out the other end outside. This way there should be no obstructions in the pipe. I always use C02 or nitrogen pressure to blow drains but that is something a home owner probably does not have.

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Using a hose and blasting from the inside drain line to the outside. I just don't understand why water would be pouring out outside while I am doing this and the drain still gets clogged. Must be that there is hardly any pressure when it's naturally draining and the hose can get past the blockage because of the high pressure. Have you heard of this before?

Dirt dauber wasps are notorious for building nests in piping. Can you run a rod or stiff wire from the open end? Does muddy water come out of the pipe when flushing? If you get it clean, put a pieceof fine wire cloth over the end.

Some AC people leave the Connection loose at the unit, may not be correct, but I see it, it is good to be able to separate and apply a short piece of 3/4 Smurf, 3/4" 90 degree sweep, then Blow through, Like you would a Blowgun.
You can do wonder with your lungs, other methods above are better, bleach down the drain works good on the algea.
If you can cap at the drain end and let it sit in there, the better.
When you are ready to turn the unit back on, flush out with water first otherwise you can pull bleach fumes in as there is a vacuum on the drain line until the trap is covered.