Merge created block resulting in not connected mesh
 

I'm new to the software so please help me.

I have a rather complicated geometry that would be difficult to handle by splitting a big block. So, I created a 2D planar to deal with one surface, converting it to 3D by translation, finally, I CREATED a new 3D block to deal with small geometry outside the original blocks. I chose "merge" when new block was created. Here's is the question, after I load the mesh from block, I checked the mesh and it was all fine. However, when I run fluent with that mesh (mesh check is good), fluent seems to see different CREATED blocks as different domain and the fluid would behave like hitting a wall when flow through different blocks. I tried merge meshes and it would totally ruin my mesh. Resolve refinements would show the mesh has no couplings. What should I do? Is merging different created block wrong and should never be used?

By the way, how can I delete a part without deleting the geometry. There are times I created parts and regretted it doing so. I wanted to have different combination of geometry to be created as a part but I can't delete the old part without deleting my geometry. Is there anyway to dissociate parts from geometry?

Many thanks!:):):)

Assign same meterial to both blocks after merging vertices.

Vertices were automatically merged when I chose "merge" when created block. And, is material same as material point? I assigned all of my different time created blocks with the same material point name, and I ran Flood Fill it shows
39618 elements are in part FLUID
125 elements are in part FLUID
10500 elements are in part FLUID

It seems I still got three different volumes that are not connected?