DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   HVAC (
-   -   How to unclog condensation drain pipe in attic (

rpguy4 06-05-2010 08:35 AM

How to unclog condensation drain pipe in attic
1 Attachment(s)
It appears that the condensation drain pipe attached to the attic unit maybe clogged because the drip pan is filling up. Fortunately, the drip plan has a overflow sensor on it, and it shut down the unit, which happened this week
for the first time. I have emptied the drip pan twice and, there does seem to be water coming out of the drain pipe outside the house. Maybe its just partially clogged or there is some other issue going on ?

Attaching a picture of how the drain pipe is attached to the unit. There appears to be no easy way to clean or check this pipe.

Please advise

Thanks for your help

Marty S. 06-05-2010 08:59 AM

Got a few options. I'd open the coil case up and pour a half gallon of beach into the condensate pan first. Most of the time it's slime mold growing in the pipe that causes the plug or partial blockage. Bleach kills the mold so it flushes out instead of clinging to the pipe walls. Second option is blow it out from the other end then clean up all the gunk that comes out. Third is cut apart up top, blow out and repipe.

Houston204 06-05-2010 09:00 AM

The 90 on top of your trap should have been a "T" with a cap to allow servicing the drain.

<$20 at a hardware store...
3/4" threaded male, 3/4" "T" , 3/4 " slip cap (do not glue this cap), 3/4" trap, two 3/4 " couplings, stick of schedule 40 pvc, teflon tape pvc glue.

You will also need something to cut pvc, and some channellocks.

rpguy4 06-05-2010 09:12 AM

Follow up
Thanks for the help and advise.

What about the idea of drilling a hole at the top of the trap, big enough to get a funnel or small bottle brush into the pipe to clean it out,
then seal it with some putty or tape afterward ?

BTW - there is some water that does get drained to the outside of the house. (brown water). Once I emptied the drip pan the AC does work, and does cool the 2nd floor. Air flow does not appear to be a problem either.
Hopefully, this pipe is only partially clogged.

Houston204 06-05-2010 09:30 AM

Sealing your drilled hole with a bolt and teflon tape would allow future cleaning. Too bad the pan isn't under it though, that's why I didn't recommend it.

rpguy4 06-05-2010 10:14 AM

Follow up
Quick note: I put a cup under the the drain outside, and in about a 1/2 hour time, that cup (1 cup measuring cup from the kitchen) was full and had overflowed. However, went back up to the attic, and I still get water dripping out of that cutoff pipe that drips into the pan.

I guess there still be a partial clog.

Thanks again for taking the time to respond to my questions

beenthere 06-05-2010 01:07 PM

Use a shop vac on the pipe outside, to suck out the restriction.

All times are GMT -5. The time now is 08:30 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1