Hi Todd, yeah like Burr mentions one issue is that pipes just barely graze one another, that can sometimes be bad for booleans.

Here's a screenshot of this part:






That may be better to have them either aligned to one another or possibly slightly separated rather than having a very thin intersection, thin slivery intersections can then generate little tiny surface slivers which tend to cause problems.


Then actually a bigger problem is with the joints of the pipe:




If you look there you can see that there are some edges internal to that joint. They are all joined up to one another, but if I use Edit/Separate to break this into individual surfaces and move them apart a bit, you can see what is happening there:




So actually something went wrong with the booleans for the pipe elbows it looks like, that then made an object that has a kind of self-intersecting internal part to it, which is going to pretty much hose booleans with that object after that.


Those can probably be repaired, I'll give a try in a bit.

- Michael