Gurgling sound in AC primary drain line.

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  #1  
Old 06-26-11, 12:17 AM
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Gurgling sound in AC primary drain line.

I'll try to keep this brief, as it's been a saga!

A couple of months ago, saw water dripping out of my AC drain holes on the side of the house. Went into the attic and the drain pan was full, rusted out, etc. I called the AC guys and they replaced the drain pan and rerouted the servicing line to the front of the unit instead of at the back of the unit in a very hard to reach crawl space. Things seemed fine.

Couple of days ago, I noticed water leaking again. Went upstairs and the pan was filling up again. I poured bleach down the T connector but that didn't help. I called the AC guys out again, they said the primary drain line is clogged. They blew it out, but said if problems persist, I would need a plumber. Well two days after they left, problem still happening.

I went to the sink where the AC drains to, and took the P trap off the bottom of the sink. When I did, immediately some water started to gush (main water was off already) and I saw a huge clump of hair descending down. I fished it out and fished out some crud from the AC drain line itself. I could feel air blow out the end of the line and the water running steady.

However, I noticed that for like 30 seconds when the AC unit comes on, it will still leak water out the primary drain line into the pan, then stops, which is better than before when it did it all the time when on and never stopped. I have blown out the line both ways myself with a compressor, and I have poured hot boiling water down the servicing T connector on the main drain line. However, I still want to know why water is still leaking into the pan for those 30 seconds at a time when it initially fires on.

Also, a new problem I have now is that the sink has a gurgling noise on it, whereas before all this crap started it did not. What is causing it and how to prevent it. do I still have a problem with a clogged line? thanks for any help guys!
 
  #2  
Old 06-26-11, 09:34 AM
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Fill the trap with water, that should take care of the gurgling. As far as why its leaking into the secondary pan we really cant tell you without being there.
 
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Old 06-26-11, 10:49 AM
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As mentioned, hard to tell without seeing the set up. A picture will help a lot.
 
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Old 06-27-11, 12:13 AM
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Update -

First thanks for the answers guys. Here is some more information as to what is going on.

First, the gurgling sound is gone. Filling the trap with water did it! Thanks!

Now, the issue about it leaking into the drain pan from the primary drain for the first 30 seconds? It starts up as soon as the unit does, but then it stops after a couple of minutes. The other unit upstairs doesn't do this. One thing is strange is that I wet vac the drain pain tonight bone dry, and then an hour later went up there and still there is some water showing up due to all of this.

On other thing I noticed is that on the outside of the unit I am seeing condensation. Now it is Texas in the summer and this is the attic, but I don't know if that is something pointing to a bigger problem. One thing is for sure. I don't think the line is clogged anymore as it's draining water for the most part fine on the primary line. I have some pics below.



This is a pic of the setup. The AC guys set it up this way 60 days ago because this used to be on the back of the unit where I couldn't access it. That valve point down towards the pan on the right, that is the one that is draining that I have been talking about.


This pic hopefully shows the condensation on the side of the unit. See right on that silver tape some water drops.




Edit: The two drain holes for the emergency drain pans are located on the second story right under the overhangs. I assume that is normal?

I keep hearing about a main condensate line that you can suck out. I looked near by units on the ground and the only thing I found coming out of the side of the house looks like a copper pipe facing downward, which i right behind one of the units. The only PVC looking thing is near the cable box, but that goes right in the ground so I don't think that's it.. Could the copper pipe be it?
 

Last edited by motc7; 06-27-11 at 12:54 AM.
  #5  
Old 06-27-11, 08:30 AM
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Drain pipes looks fine, you need to open the air handler and see what is going on inside. If everything works, you should not see any water in your secondary drain pipe (the short one) which you can see is a little higher then the primary. The condensation may be caused by a small air leak. reseal the area may help. In newer system, primary drain does not go outside of your house, it goes directly to the plumbing system, so you won't see the opening of the pipe. the one you see outside may be for your hot water tank.
 
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Old 06-27-11, 09:04 AM
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The air handler, would that be over in this direction?

 
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Old 06-27-11, 10:55 AM
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There should be a panel you can open to access the coil. the drain pan should be under the coil, and also the inside of the drain ports(one primary ,one secondary) .
 
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Old 06-27-11, 11:03 AM
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where typically is that. Is it on the first picture I posted, or in the last one I posted in one of those panels?
 
  #9  
Old 06-27-11, 12:02 PM
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Well, I broke down today and got a second opinion from the AC folks. Found out the problem, and that is apparently, the house has shifted and as a result of that, the primary drain line is draining down and around the walkway in the attic, then coming right back to the unit. Thus causing the "leak".

His suggestion is to come straight across from the unit, put in a T for pouring bleach down and blowing out in the future, and connect it to the other unit's primary drain line, which there is enough of a slope to do that. Said problem should go away instantly.

Thing is going forward, gotta be careful walking around in the attic! I'll let you know the outcome of things.
 
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Old 06-28-11, 10:48 PM
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update:

Well, from the way things look so far tonight, I think I fixed it! Here is what it looks like now.

This is what the other unit looked like tonight prior to work. you can see on the right where that line that was too low and causing the backup is.



This is what I did afterwards. Only made two cuts.




This is the modified version of the problematic unit.




And here is where I connected it to the other unit's drain line.




All in all, I got separated from some money with service calls, but on the brighter side, I know more about HVAC that I ever did before. I have checked it three times so far and not a drop dripping anywhere, including the PVC screw on fitting for the drain.
 
  #11  
Old 06-29-11, 08:59 AM
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I don't really understand how you fix your problem, but what important is the problem is now fixed. Good work.
 
 

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