HVAC-Talk: Heating, Air & Refrigeration Discussion banner

Primary Drain Line Clog

670 views 4 replies 3 participants last post by  McBridePride  
#1 ·
Hello There!

So my primary drain line on has finally clogged and my secondary drain line has been basically almost flooding the garage without manually emptying the water from the pain I have under it twice a day. So naturally I started to get to work on the clog.

I am also not afraid to admit that I had no idea that the drain line needed to be properly maintained. This was advice I was never given nor had any idea about as this is my very first home i have bought and it was built in 2009. Now I know that i need to and researched how to, so I will be doing that going forward. But need to fix it first now.

First I went and attempted to auger the line, from both sides (end attaching to HVAC and end that runs outside the home by the actual AC unit. No luck. I then also attempted to shop vac from both ends as well which also did not clear the clog. So then it actually require me to look at the plumbing of the line. I noticed that first and for most, there wasn’t even a proper P Trap installed, when they built the home, the just used two 90 degree elbows to make their own p trap. Also I took at my level and all the lines were actually level, there was no minimum of a 5 degree downward slope. Now I’m not sure if this is compliant or not, but since the nonintrusive methods did not work, and I felt that the line first of all was not even up to code with the half assed P Trap and no slope, I have now cut the line and am going to re-pipe it.

Picture of the current drain line:
(Actually never mind - I just created the account and don’t have enough posts to post Imgur links - sorry)

Basically now with the back story out of the way, what I’m specifically asking here is a couple things:

1. Are there any absolute do or do nots when re-plumbing my primary drain line that runs under the house and out to the outside right behind the AC unit? I know to get a proper P Trap and also try to maintain a 5 degree slope.

2. What do the pros recommend as the distance after the p trap to put my vent/maintenance port in?

3. For my secondary drain line that literally just has 90 degree elbow with about a foot long tube that goes to the garage floor. Do I need to add a p trap to that one as well to equalize the air pressure at all? Or will it be pointless as the water in the p trap will eventually evaporate and then cause air issues anyways?

Thanks for any and all advice given! And sorry if these are ignorant questions. When it came to maintenance; I honestly just had no idea. Nobody ever told me. It’s one of those things unfortunately that most people I feel find out after an issued already happens. I really wish there were home owner maintenance run downs for all first time home buyers as part of the buying process haha.
 
#2 ·
Well, if the line goes under the house you will have it double trapped. That's a no-no. Remove the upper trap. 2 glued elbows are hard to clean but common practice in many installs. I'd put a capped T about 2-3" from the coil exit, and maybe another one right before it goes under the house. Secondary lines don't need a trap.
 
#3 ·
The install manual for the air handler or coil should specify drain install instructions, but codes are single trap only in the entire line.
Vent after trap is ok, fully support the line the entire length, and 1/4” drop per foot of run.

I also install my trap into a tee, and put a pipe with a cap on it, for easy cleaning service.

NEVER USE CLEANING OR DRAIN CHEMICALS in the condensate drain line.

Use only chemicals specifically for ac drains.
 
#5 ·
VSTech! Thank you also for your response and expertise! I appreciate that as well! I bout a trap that already actually has a capped end at the top for easy cleaning! And I did buy some ac condensate drain tablets to actually properly maintain it going forward. Plan is to throw in a couple tabs every time I change my air filter. I also looked under the house and follow the line and there were no supports on it. So I’ve already go those and will run those to make sure I’m supporting the pvc while also maintaining my proper angle.

Does the vent need to be a certain height after the p trap? The current one was like an 8” pipe with a 45 on the end for vent. Could I get away with shorter?
 
You have insufficient privileges to reply here.