I want to install a wall box with a standpipe drain for my washing machine. I'm trying to figure out how to plumb the drain line. Here are my questions:
- Should I use 2" drain lines?
- Do I need a trap (I'm assuming yes)?
- Do I need a vent (I'm 32 inches or less from the stack)?
- If I do need a vent, where should this connect to the drain?
- How far does the vertical part of the standpipe need to go (do I need to put the trap under the floor)?
- Can I tap into an existing sink drain (1 -1/2")?

All of my drain pipes are ABS