Smeltery channel problems

[Blastoise996]

I am trying to get the smeltery to work and i have everything set up how its supposed to be. I have a 3 by 3 with the controller lava tank with lava in it, drain, and channel set up above a casting table (or whatever table is used under it) but when i right click the channel that portion of the channel disappears. i tried shift right click, normal right click, shift left click, normal left click, and then all of the above on the drain itself. Nothing seems to work. So if someone could help me out that would be great! thank you!