Do home air conditioner drains (outside) need to slope down?

Question

My drain pipe, which is flexible black rubber tubing, (1" I believe, but not pvc) does not really slope down at all on the outside of the house. It actually comes out ot the ground where the exterior wall meets the ground, in a horizontal direction. It was actually totally underground, until I dug up the area for some landscaping. I want to make a "better" one, but I am nervous because I don't want to raise it too much above the point where it comes outside, but that's impossible because it starts so low...I had an issue with it becoming clogged recently, which led to extensive floor damage inside the house. I want to make sure that never happens again, so I want to make a better drain tube, out of pvc as most of them are now. I have seen some that run horizontal, then down a bit, horizontal again, then up a bit then drain up.. What are the benefits, if any, of this design?

I am primarily concerned with the drain not clogging up with dirt on the end, and I think it should not be underground. Since the drain would start at ground level where it comes out of the house, it would be impossible to have it slope down unless I dug some type of trench or something..Is it alright to have it run slightly "uphill" a little before it drains? As long as the drain end is still at a lower level than that of where it starts, it should be alright, correct? It should have no problems of backing up water in the house this way? (as long as it isn't clogged).. don't want to take any chances, as I am about to redo the flooring that was damaged. I am having a hard time finding drainage examples to work off of online-- plans, diagrams and such..And most of what I find, the drain starts off much higher and runs at a downward slope..

Answer 1

P-TRAP is the correct answer... there is a science to HVAC and if you don't install a P/TRAP  correctly ,  you will have problems...........

Answer 2

is this unit upstairs,attic or on the ground level? if upstairs or attic you can run the drain to the drain line of a sink just make sure to bring the line before the P-trap. other than that i do not know of any reason that it needs to be sloped to drain as long as you perform monthly maintenance to keep it clean : pour bleach in it to keep algae from growing.

Answer 3

I wouldn't run any of the drain under ground, it's just another trapped area where it can get plugged.

Why can't it run to the ground just as it leaves the structure?

I don't know how the inside unit is set up or located but maybe you could use a small condensate pump kit that will collect the water inside from your A/C coil into a reservoir that will kick a pump on to pump it to any location through 3/8" tubing.

They have a switch you would wire to the A/C and cut it out if there is any problem with the drain.

We use these all the time where the condensate cannot be run with the proper slope or where a plugged drain would cause some significant damage to the structure.

Some manufactures of this type of pump is Hartell, Little Giant, Beckett.

You can find these in hardware stores for about $50.00

Answer 4

Of course..the steeper the grade the better the drain.

The larger the diameter of the drain pipe the longer  it takes to clog up.

The more often you find the end and use a wet vac. to clean it ,the less  chance of clogging and backing up into your house. Water does seek its on level and if no part of the total run is higher than the entering end at your a/c evaporator section (indooor coil) it will seep out. But if level and up hill and finally down is the case it will lay still an no volosity will be present to give sweeping action and you would have to vacumn and clean the tube often.  If you can't start a new big line and run a good downhill grade. Like an inch per ten foot run or better, Then install a small pump which is called a condensate booster pump and run a flexable line to the outside. These pumps have float switches and safety switches  and can be wired into your system controls and will turn your system off if it floods.

the pumps can be bought with different head or water lift capabilities. from about 10 feet of lift to about thirty feet of lift. you can run the tube at any level till it reaches your outside drain loacation. A pump with a ten foot lift or (head) can be used  up to ten feet above your starting point. it has a small check valve that keeps it from draining back.

It would be worth it to have it installed because it will save your floors.

Good luck.  

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