I'm trying to trace out all the heating pipe paths in my house. Foundation is on a "slab". One zone is in the slab, 11 pieces of baseboard, but there are 4 supply pipes and returns. Upstairs is a second zone, 3 supply and returns. Upstairs is a bit easier, since there are only the three baseboards to match the supply/returns. The slab located ones are what I need help tracing. Any help/ideas certainly are appreciated.