Should a toilet closet flange fit into or over the pvc drain pipe?
I had the same question, especially after installing a 3″ flange inside a 3 inch pipe. The trouble with this is that you are ‘narrowing down’ the drain opening (i.e. restricting the flow) so that clogs are more likely. I know, cause I clogged mine and then my wax ring blew out (while removing the clog), so I had to pull toliet off. I cut out my old flange and replaced it with a 3/4 flange that fit OVER the outside of the 3″ pipe. Now when you look down at the flange, you now have a 4″ hole, not a narrow 3″. The less restrictive opening should help prevent clogs (I hope).
