Hello and please bear with me. I'm no expert when it comes to plumbing but I will try to be as detailed as possible.
I'm trying to understand what a pipe does in my basement. The pipe seems to be filled with hot water and drains from upstairs down to the basement. I followed the pipe and it seems to lead to the furnace and water boiler. However from there I'm not sure if it is going to the furnace or water boiler. The pipe in question seems to be interconnected to pipes that lead to both units. I have attached some pictures of the pipes below.
Something else I was told by a plumber awhile ago was that there is another pipe on the opposite side of the wall that does the same thing that leads into the furnace room as well.
1st Picture: The is an image behind the furnace + water boiler. The pipe I'm asking about is located on the far backside on the right hand side coming through the hole.
2nd Picture: shows the pipe connections on top.