Trane XE80 - Drip pan filling up. Drain setup wrong? Please help :)


Old 06-08-14, 08:24 AM
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Trane XE80 - Drip pan filling up. Drain setup wrong? Please help :)


I really need some help. I've been fighting with this problem for 5 years and hoping someone here will be able to tell me what the problem is and help me finally fix it.

Okay, so here's the situation. I have a Trane XE 80 split system. The system is about 15 years old. I bought the house 5 years ago and the first summer the drain pan filled up and the float in the pan killed the A/C. I found insulation stuffed in the clean out pipe, removed that and cleared the pipe and it's worked since. Now the problem is back... From the research I've done, I think the system may be set up wrong.

From the photo below, you see two 3/4" pvc pipes connected to the drains. Excuse me if I'm using the wrong terminology. The one to the left that is pointed to 10 o'clock fills up to the top and water then drains into the drain pan. The one on the right of that, runs out of the attic, down the wall and outside the house. The first time this problem happened, the cleanout on that pipe was stuffed with insulation. I cleaned it out and water started running down and out of the house and it worked fine for 3 years. Now, the same situation is occurring.

The drain pointing to 10 o'clock fills up and eventually water runs out and fills up the drain pan. The problem is that the drain on the right, the one going out of the house, never gets any water in it. If I look into the cleanout, I can see that its barely wet on the bottom of the pipe. There is cold air blowing out through the clean out, telling me that the pipe is not clogged. But for some reason, there is no water draining through it, and it's going to the pipe that's pointing at 10 oclock and into the drain pain.

So my questions are:

1. Is the pipe on the left supposed to be draining into the drain pain? Meaning, did someone mix them up.

2. Is the pipe on the right supposed to be the one draining out of the house?

3. I read that on some units there is a drain into the house plumbing. Is there or should there be another drain somewhere on this unit that goes into the plumbing? Meaning these two are the secondary and third draining methods?

4. The two holes, one with a plug in it, about 1 oclock from these pipes I'm assuming are the drains for then the unit is installed standing up. Should the hole that is not plugged be plugged?

5. I read that the clean out should have a cap on it, is this correct?

6. Let's say that the pvc is hooked up correctly. For some reason the drain on the left is filling up with water, but the one right next to it, at the same level is not... which doesn't make sense. Is there some sort of divider inside the unit on the other side of the panel that could be clogged? I'm guessing something has to be clogged on the inside to cause one of two drains that are on the same level to not drain water.

If someone could help me make heads or tails of this and what I need to do to correct the problem, it would be greatly appreciated. The previous homeowner was a DIY'er... but I've had to fix most of his DIY projects and I'm assuming this will be another one

Not that it's related, but I have changed the circuit board, inside and outside capacitors and the flame sensor in this unit over the past 5 years.

Thanks in advance!

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Old 06-08-14, 09:11 AM
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I cannot tell from your picture but the lower of the 2 drains on the evaporator coil should be connected to the primary drainline.

That is a positive pressure application so the pvc T should not be capped.

I would like to see a pvc T between the p-trap and the evaporator coil to allow you to blow out the T without sending the dirt back into the evaporator coil.

I would also pipe the secondary outlet on the evaporator coil down into the secondary pan then add 2 more 90's to form a small trap. The secondary should not be at 10:00 it should be at 6:00.

The secondary pipe normally runs outside above a window and the primary drain normally runs into the plumbing with that application.

I usually do not install a trap in positive pressure primary drainlines unless it doesn't run into a sink or plumbers hub that already has a trap. I do trap the secondary outlet to stop positive pressure from forcing a drip out of the secondary outlet which can cause a rust buildup in the secondary pan over a few years.
Old 06-08-14, 04:20 PM
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Thanks for the reply.

One of the main problems is that both of the drains are level with one other... so I can't tell which is the primary and which is the secondary. If you look at the two drains that are vertical up and to the right a little, they are in line as well. So if the unit was installed on end, they would be level as well. That's where most of the confusion is coming from... and why I'm hoping to find someone with experience with this model. Both drains are level to one another and the one on the left is draining into the drip pan. The reason it's at 10 O'clock is that I was trying to force water into the one on the right, which didn't make a difference.

So I need to know what's behind those drains in the unit, as I'm thinking that's where the problem lies. For one to be draining and the other not, I'm guessing there is some kind of divider with a drain from one side to another that is clogged...

I don't know if I can take the top panel off and have access to the bottom half or if I have to disconnect everything to get both the top and bottom off to access whatever is behind those drains.
Old 06-08-14, 06:08 PM
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Usually there is nothing on the inside of those lines. It is very common for the primary drain to plug up with dust and lint. Cut the PVC going to your right fitting and remove it. It's only PVC so it's easy to redo it. Once you remove the fitting you'll probably see the clog.
Old 06-09-14, 11:12 AM
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Thanks. That's going to be my next step... The fact that cold air is blowing out of the clean out is sort of telling me that the pipe is not clogged... it's a pretty steady stream of cold air. But I don't have much of a choice at this point.

I'll update later.

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