Originally Posted by diy888
My questions are
a) is the basement sink waste pipe in the diagram within code?
b) The washing machine empties into the sink. and the sink empties very slowly; we have a lint trap on the hose. Would the speed of draining be improved by an air-admittance valve placed about midway along the 56" length?
The sink was in the house like this when we bought it 20 years ago.
2" copper waste pipe travels from the sink drain 56" along the wall, makes a left turn and continues for 29", then makes another left turn and continues for 15", whereupon it goes down into the basement floor (concrete). About 18" from where the waste pipe enters the floor is the 4" vent pipe. The vent pipe is about 69" from the sink drain measured on a diagonal, though the linear run of the pipe is 100".
There is no way you have proper slope.
To answer the air admittance valve question, no don't put it midway, put it where it's supposed to go.
The order should be AAV, then trap, then drain pipe leading to the main drain.
Do a google search for air admittance valve if that explanation didn't make sense. Look at a diagram everything will be clear.
Yes, the AAV will help, but it won't fix your problem.