A canister is attached to a header tank and includes an upper inlet and a lower outlet. Before end cap is brazed to close the bottom of canister, a tube of desiccant material is installed into the canister by a standoff. The standoff includes a disk shaped base and narrow central post which is comparable in length to the height of the inlet above the lower end cap. This is followed by inserting a spur of a higher melting temperature into the canister into a position and extending radially from the post and into an interference fit with the interior wall of the canister that is tighter than the interference fit between the base and the canister.