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.