: I had a new high-efficiency furnace installed recently, and something looks a little odd.
:
: There is a discharge hose leading away from the furnace, to drain excess condensation. There is no convenient floor drain, so the installer used a "T" to tap into an ABS drain pipe which is nearby. The pipe in question is a vertical drain for a bathroom vanity (rough unfinished side of the wall), on the street-side of the p-trap. It runs up to a stack and down into a drain beneath the floor.

: Is this wrong, and should I have it corrected? It seems to me that anything running into a drain pipe needs to have its own p-trap - or needs to be installed on the sink-side of the p-trap, as a dishwasher hose is connected.