Gurgling Condensate Pipe Expels Water

OP

Attached a picture of my setup. When the furnace kicks on, there is a loud gurgling (and I can see it bubbling) comes from the vertical pipe on the left. Eventually it starts spewing out due to the force.

My home was constructed 2 years ago and this never happened before. It first started gurgling a few days ago and then only last night to it start spewing out. Is this configured properly?

I have no knowledge of how these should be setup, but I would think the way the pipe on the floor is laying flat, it will completely fill with water because both ends are elevated. So, the air coming down the right pipe has no where to go but through the water. Maybe this is down purposefully for some sort of condensing process?

AP1

It looks like drain system is double trapped; once at the grey plastic built in trap at the side of the furnace and again at that goofy rise on the other side at the ground. Probably allowed drainage when new but now has a partial blockage. It is a condensing furnace as you note and makes water. The AC drain has more head room and will over come the second trap, the furnace does not and already has a trap to overcome. Or maybe it's just completely blocked at some point beyond the furnace. Have someone come and lose that second trap and clear the drain. Is there some reason for the riser on the ground that we can't see? (This answer said it all, OP should stop questioning and redo the second trap)

OP

Added a picture of the end of the pipe and drain. I don't know the purpose for the rise. My guess was because it looped down into the drain a bit, but I don't know why they couldn't have just used a regular elbow to do that. (They probably ran out of elbows at the time and used a trap to terminate this condensate line.)

So, you think the water is probably getting trapped in the pipe as well due to the riser? That was my guess, but I didn't know why it wouldn't have been a problem for 2 years. (Because the pipe wasn't clogged during this time.)

AP1

That's a fundamental plumbing no-no. The furnace drain is only coming at the main drain in the floor at whatever trickles over the first trap at the furnace. Is there a humidifier in play as well tied in where we can't see it? Might want to make sure it's working as it would add to the flow. Still...I don't believe I've ever seen an upside down trap used as a drain termination and it is not right. As you know...water doesn't naturally flow uphill and needs some encouragement.

AP2

However, that particular drain on the Goodman is vented to atmosphere right where it is, so water being gravity driven will do that hump....I wouldn't have done that and just put an elbow too. Would like to see pictures of the rest of the condensate piping........ Might just be a clog and pressure from the A/C condensate drain. I can see that its damp around furnace trap....so water is coming somewhere.

OP

Here's a picture of the full set up from one angle. I don't know enough to know whether there is a humidifier involved.

AP3

I bet the A/C coil drain is not trapped, causing the supply air to blow into the drain and gurgle. (This observation doesn't help because water in the trap would dry out in the wintertime.)

OP

I can replace the curved part of the pipe by the drain on my own with a simple elbow. Should I do that as a first step to see if it resolves the issue or do you guys think I need to have someone come investigate? (OP already got all the info he needed, why would he needs more?) 

AP4

Your installer didn't pitch the flues correctly (This is just stupid), or your son threw something inside the flue pipe. Or maybe a bird. (If this would be the case most likely the pressure switch shut the furnace down.)

AP3

Doesn't look like the gurgling has anything to do with the venting, it's coming from the trapped water in the drain pipe due to the air pushed down from the a coil drain.

AP4

When your partially restrict a GMH's venting, the pressure from the inducer overcomes the restriction in the trap, causing water to splash out from the trap.

It trips on P/S. Then retries.
If it's a bird, it will do it over and over, in quick succession.
If it's an incorrect flue, where water lays in the pipe, the water will build up, splash, trip the PS, drain, run for bit, and go over and over.
Sadly seen it many times. (Well, OP never mentioned anything like that, so why bother?)
Are you suggesting that the air from a coil is forcing water 2' up a 3/4 PVC pipe? (This is a fact, some people just don't like them.)

OP

I watched it more closely and the water getting expelled isn't getting force up from the bottom.
What is happening is the water trickling over into the pipe... the air coming up the pipe is hitting it as it comes over the edge and splashing it out.

I have the original installing company coming tomorrow to look at it.
I guess my question at this point, can you guys see that the installed these pipes incorrectly? Is there a trapping issue (whether wrong or missing)?
I don't want to pay them to fix anything if they did it wrong in the first place.

AP5

Have them trap the A/C condensate pipe then vent it immediately after the trap, so when it dries out it doesn't blow up the vertical pipe to the furnace trap. Then get rid of that riser near the termination. Add pitch from the tee at the floor to the termination. The installer did a great job with everything else. Perhaps he will learn from this and his installs will work as good as they look.

OP

So, the only thing they did was add a tee to vent at the top of the A/C coil drain pipe to let the air escape there instead of back up the furnace condense drain up.
He said the riser at the end near the drain was correct and the only trap needed for those two drains. He said traps aren't even needed because there's no "gas" in these pipes. Like the previous poster said, the manual for the A/C coil does show that a trap is needed.
He then told me if the problem continues to go ahead and just remove the riser at the end and replace it will an elbow to go down the drain.
So, is this a satisfactory fix? It seems to have stop the gurgle, but could it lead to other problems? (If the pipe is partially clogged it could be a problem in the future.)
I also asked them why I should have to pay for this, and they said that it passed inspection when our home was built, so that takes the liability off of them. (I don't think this is right. All we know an inspector is a human and can miss something. For example my friend got his furnace replaced, and inspected, but an installer cut transformer wires for humidifier and never hook them back up to the new one and no one even noticed.)

AP5

It is fine the way he did it but you could have done that yourself. When you call a company out, expect to pay the bill. Personally I would have removed the inverted trap and added a trap to the A/C condensate line. If it bothers you, fix it. It will probably be less than 5 bucks in fittings.

OP

I thought DIY was discouraged on here, so I didn't want to get banned from the site for taking everyone's advice on here and then doing it myself. I'm completely comfortable redoing the piping myself, but I just wanted to know if what he did is the proper solution. I was trying to read about the purpose of a trap on the condensate line and I was getting the impression that the goal was to prevent air from going through the pipe (in or out) and maintaining pressure. What he has done doesn't do either of those things. He tried to tell me the only purpose of a trap is to prevent "dangerous gas" from escaping and that these pipes don't have gases in them which is why he said it wasn't needed. Based on everything I read... he was just feeding me some BS. (I understand OP's frustration, but as I mentioned above he could've fix the problem himself long time ago! And this is all my website is about. Learn how to do something and do it yourself.)