What is THIS?

This is a drain pipe next to the water heater in the attic. There are several pipes going into it: TPR, drain pan, thermal expansion valve and one other that comes off the cold water and has a valve.

The PVC looks like 4 inch pipe and narrows to 2 inch pipe in about a 5 inch length. I do not know where the 2 inch pipe terminates (not outside).

Three of the four pipes terminates just inside this “bowl” and the one with a valve appears to run inside the 2 inch pipe to destinations unknown.

Whew, there I said it all, now… What the heck is it? It is full of debris and when I opened the TPR, it filled up. I stopped and it slowly drained down to about 2 inches of standing water.

Any ideas O Wise Nachi MB-ers?? Help!

As always, thank you in advance.


Thing - compressed.jpg

Looks like problem waiting to happen.
Maybe a ‘p’ trap further downline?
TPR should drain to exterior - not into internal plumbing.

Oh I know, it’s got “BAD” written all over it. I’m just wondering if this is some newish plumbing concept I’ve not seen.


PS Where on earth is Utopia, TX?

If I was to take a wild guess being you stated it was in the attic you are probally viewing a drain line tapped into a vent stack and hopefully the water you are viewing is the water in a P-trap to prevent sewer gas into the attic.

I would much prefer to have the drains on a safety pan and the TPR discharging into a drain in the attic than on to the dry wall ceiling below.

SOP’s in this State does not require operating the TPR and I do not as too many of these valves will not reset and then you have a terrible mess to explain.


I agree with Charley and I also wonder how much insulation it took to cause that clog?