My hydronic system has a loop (or ladder) that visits baseboard radiators on four floors. All piping is hidden in the walls.
On the attached diagram, squares are windows, red is baseboard radiators, and black lines are potential configurations of the pipes in the wall. The tops of the black lines have bleed vents.
I would like to install Danfoss valves (TRVs) where the blue circles are, but this will only work if my hydronic system is in a 'ladder' configuration, rather than a 'loop' configuration.
Are most systems set up one way or another? Are there good ways of telling, short of ripping holes in the wall?