I have an existing bathroom with sunken shower area 30" x 72". I will install a drop-in bath into this area (procedure: four brick walls, tile on the open wall, plaster base to support).
There is a floor drain in the existing area, which is essentially a 3" hole which drains into a 1.5" pipe. I think the installer misunderstood '3" floor drain" as meaning the exit hole, not the input hole, as they have connected it directly to a 3" pipe, not a 1.5" pipe
That 3" pipe is punched through the slab and goes immediately into the actual, unvented, 2" waste pipe
The floor drain looks like this one:
There is a related question here, where it's argued that the drain cover should not have holes in the middle
What type of floor drain is this and can I connect pipes to it? and here: How to connect bathtub drain pipe to existing floor drain?
This is not the case for most floor drains in use here in Indonesia.
There is another kind of trap here: Is this shower trap better than a P-Trap?
It is not that either. It's similar to this except 1.5", not 2" pipe:
So questions basically:
- Is it ok for me to dump my bath water over it, while continuing to direct water towards it from the rest of the bathroom
- it seems that it's a slightly questionable design in terms of sewer gases etc. Should I fit a 2" PVC P-trap in place of the current 2" elbow below the slab?
- my bath comes with plastic (p/s-trap):
If I am to dump my water into the floor drain, then I guess the bath's trap isn't really doing anything and I can leave it out if convenient?