[rbogh901]

Guys, hey, can someone explain a basic concept I've been hunting: How is the primary length of headers measured? I assume it would be down the middle of the tube and be an average of the shortest and longest distances within a primary.


Does it end at the merge or at the mid confluence of the gases?

In other words, when primary length is specified how is it measured?

Maybe it's been addressed here but I haven't found it. Some great discussions overall but this one eludes me.