AC drain pipe clogged

I've had success with a water hose. Basically try to seal up the mating face as best as possible and push through.

May also be a good idea to make sure the outlet of the drain is open, assuming it drains outside. Run a clothes hanger or wire as fall up, make sure nothing has made a home in the pipe.

Is it your evaporator coils in the furnace that's having the emergency pan fill?

We were conveniently out of the house for a few hours after the A/C shut itself off, so I'm guessing once I drained it and kicked it back on, there wasn't any residual moisture to build up on the coils.

Pour bleach down it with boiling hot water. We have a small pipe we can pour into so I blow into that several times to make sure I can hear it drain and also to push some of the hot water through. Haven't had problems since it happened at the end of February

I've also used a water hose. From the outside in, make sure your vent cap etc is attached well so you're not spraying your attic with water.

Sometimes you need to give bleach some time to clear it, how long has it been? I mean shouldn’t be more than 30 mins or so. But bleach kills algae build up, it’s possible your line has something else in it but that’s not normal.

Does your line drain outside or drain into your sewage plumbing? If into your sewage plumbing it’s probably an issue where it T’s into your sewage line.

Sometimes a really slow drain will prevent the bleach from doing it's job too.

Plug up the drain at the exit (if it drains to the outside.)

Then pour in some bleach mixture until it's full.

Let it sit to soften up the plug.

Open up the outside plug and use the shopvac to suck it out as best you can. Might need to use tape to really seal it up.

The garden hose method can work well too. Just be careful that you don't overpressurize the PVC. Some of these drain setups aren't exactly the most stout. It would really suck to break loose a fitting in the wall.

At the beginning and end of summer, it's probably a good idea to flush out the condensate line.

Maintaining the slope from the pan is important as stated and if the clog recurs in a short time, within a year or so, it may be farther down in the main drain.
I found a taped access point on the vertical drain and ran a 10 ft section of PVC down it and encountered a blockage. Cleared it and have not had a problem in 12 years.

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Tried the shop vac from the inside on the vent.

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you dont do it on the vent, that does absolutely nothing since the vent only has air in it.

you cut the main drain line leaving the unit and use the shop vac to suck out the clog.

if you cut the main drain line at the unit and water comes pouring out then its the line that is clogged and you can usually blow hard with your mouth to make the clog go through the line to clear it. if not then use compressed air to do it

Hose worked for us. Heard a huge pop and something set loose. Never had the problem again. Bleach just wouldn’t do it.

Happened to me few days ago. Shop vac from the outside drain on and off sharply about a dozen times I think got it.

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seems to drain the liquid I pour in

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Pour more bleach, then boiling water. Probably got a bit more of that algae to break up.

You can blow it in from the top either with compressed air or by creating a fist with a small hole and pushing air in with your mouth.

If you can confirm that it drains into the gutter, you should see it come out. I believe ours drains into the sewer. I never confirmed but it made some amount of sense because we had a leftover bottle of lemon scented bleach that we used and the house smelled like a cleaning store shortly after.