We had an old Lennox furnace that was located in our house replaced with a gas pack/ac combo on the roof (I am in Phoenix, AZ). I want to clean up the old furnace closet. We have a house built on a concrete slab (common in Az) and it was built in about 1952. There are three pipes in the floor of that closet where the old furnace was removed from, one is a drain located roughly under where the double wall vent pipe is located in the ceiling - very rusty in side. the other two pipes go down about 8" into the slab on the other side of the closet. When I put a wire in the two pipes on the other side of the closet and peer down with a flashlight, it looks like they go somewhere, the wire does find an elbow down there in those two pipes, but they dont look blocked and are not rusty. These two pipes I mention were never connected to anything when we moved it (it may have been for a previous furnace that was removed, but who knows...) The first pipe i mentioned i cant tell if there is an elbow at the bottom, it is very rusty inside and full of rust flakes and hard to see and when we moved it it was connected with a plastic pipe to the furnace, if memory serves correctly, but I think this drains to the outside. My questions is, can I cut off all those pipes at floor level and fill them in with grout since the furnace is gone? I think they are just ways for bugs and geckos to get into the house. Many thanks in advance, bob walker, phx az