PVC Condensation Drain Pipe Clogged on A/C in Attic

[BigChiefNocaHoma]

(First of all - may I please be granted the Cone Of Safety for not using the proper terms for A/C parts; I am just a housewife who happens to fix EVERYTHING in the house because my husband doesn't know the difference between a flat-head and a Phillips head screwdriver; forgive me if I call something the wrong name...)

We have two A/C units - one in the attic for upstairs and one in the basement for downstairs.  In the attic unit, the drip pan underneath the cooling coils is completely full of water and is overflowing.  My daughter came running downstairs to tell me it was "raining from the ceiling" because the water had overflowed enough to drip from the unit into the attic, through the ceiling and down through a light fixture :poison::poison::poison:.  Luckily we caught the problem quickly...

There is a PVC drain pipe that comes out of the drip pan, goes to a "trap" (gooseneck/u-shaped pipe), and then connects to a long PVC pipe that runs towards the front of my house (along the rafters in the attic), makes a 90 degree right turn, runs along the rafters to the side of my house, and then outside.  The pipe runs through a gutter and then it connects to a flexible plastic tube that drains water onto the ground.  I know the drain from the drip pan and the "gooseneck" are clear because I disconnected them from the long PVC pipe, and the water from the drip pan drained freely into a bucket.  (However, no water came out of the long section of PVC pipe when I disconnected the pipes.)  There must be some sort of clog in the long section of pipe somewhere between the gooseneck and the ground - otherwise, why would the drip pan be overflowing?

If there is a clog, how the heck am I supposed to clear a 1/2" PVC pipe that runs for probably 60 or 70 feet?  I obviously can't snake a drain pipe of that size.  Any other suggestions for clearing this pipe?  Should I try a funnel and Drano or Clorox?

Am I making any sense?  It was only about 1,000 degrees in my attic when I was figuring all this out, so the heat may have gotten to me...

[dkpd1581]

Start by pulling off the goose neck (P-trap) and trying to clear it from there.  Usually clogs are there. 

If not, try snaking from each end to see if you can find the clog in that fashion. 

If not, use a good wet and dry vac and try to attach it to the outlet at the bottom of the PVC run from the outside and see if that will move the clog.

If not, we use high pressure nitrogen from the top to try and move the clog.  You may have access to a protable air compressor.  They make a device that we call a Drain Dog that is like a long rubber ballon that expands and seals as the pressure builds up from the nitrogen. You will not be able to hold enough pressure by hand.

If not, tapping, banging, or shaking the PVC can help move the clog.  Give these a try in this order and let us know.  Once the clog clears, run a mix of Chlorox and water though the line (about 1/2 gal) every month to help keep it clean in the AC season.  Nothing fancy, 50/50 3 to 1 ... whatever you care to mix it.  Just do it to clear out the slime that builds.

[Brew Man]

Hey,

You can try to use one of those cans of drain cleaner that works off of air.one simply pushes on the end of the can and it shoots a burst of air through the line.This may be enough to clear the line. You can try connecting a water hose to one end and let the water pressure push it out.

[BigChiefNocaHoma]

Thanks for the suggestions, folks - everything seems to be running (and draining) smoothly now.  I think I must have unclogged the drain pipe when I initially disconnected the gooseneck pipe and cleared out the drain from the drip pan, because the pipe is draining perfectly now.  I'll make sure to periodically run a Clorox solution through the drain for preventive maintenance from now on, and I think I'll be keeping the bucket underneath just in case!  Thanks again for your help...