I've found either an error in the manual or a defective part.

In the assembly instructions at Task I, step 6, the instructions say

"Insert AV-640 Coil Assembly (LI) 4 inches (10cm) into tubing section
BD."

However, LI can only be inserted 3 inches into BD before butting up
against the smaller diameter tube nested inside of BD.

The overall length of BD is 75" as documented, and the smaller internal
tube sticks out the far end 3".

How did yours go together?

--
Bert Hyman W0RSB St. Paul, MN