I'm replumbing my laundry room to accomodate a stacked washer & dryer and have two questions about the drain pipe.
1) The old drain, a 1 1/2" ABS standpipe, doesn't appear to have a trap. Is this typical for washing machine drains? I think I can fit in a running trap (U-trap?) if needed.
2) An old general home repair book advises installing the drain pipe so the outlet is no lower than the wash tub water level -- to "ward against overflow." Since the book was written about 25 years ago, I'm wondering if this still applies. The manual for the new washer gives instructions on the maximum height for the drain but says nothing about a minimum height. I could possibly get the pipe up to the level of the tub, approx 35", but in the same wall where I'm working there's a vent pipe in the way. Otherwise, the outlet will be about 27" above the floor.