I recently did some renovations, which included moving a washer and dryer upstairs from the basement. I did the plumbing myself with the guidance of a plumber, but I'm having a problem.
Before the renovation, the drain line from the water softener emptied into the washer drain, which then carried the water through a wall-mounted pvc pipe into the septic tank - the basement in this area is unfinished. The washer was moved upstairs and installed directly above its former location, so I just extended the washer drain pipe up through the floor. I also ran a vent pipe from just past the washer's p-trap. I then installed a new p-trap in the horizontal run of the washer drain pipe, using a Mr. Drain air gap device which connects with the water softener drain line. The new p-trap is done with a sewer tee. From the tee, a vertical 8-inch section of pvc connects to a 90-degree elbow, which then connects to the trap. The air gap device is currently stuck into a piece of pvc which extends another 4-5 inches above the trap.
The problem I'm having is that soapy bubbles from the washer occasionally make their way out through the air gap. This does not occur every time the washer runs, and the amount is always small - I'd estimate about 2-4 cups of liquid. Also, it seems to happen most often when the washer is emptying during the first drain cycle but not the subsequent ones - only when the soap is in the washer basin. If I fill the trap with a glassful of water just before running the washer, it seems to reduce how often this happens but doesn't eliminate it, so I don't believe the water is evaporating out of the trap faster than the water softener can refill it.
What do you all recommend to fix the situation? Would a deeper or taller p-trap that can hold more water fix it? Some sort of check valve? It's more of an annoyance than anything - a bucket placed under the p-trap catches most of the water - but I'm tired of the situation.
It's hard to follow exactly what you have; a picture or a drawing might help.
What size is the drain line? It should be 2". If a trap is emptying, it's likely things are not vented properly. Make sure you're using the proper detergent and amount with the WM...the wrong one or too much can be a big problem.
When you moved things, you had to move the trap. Keep in mind that once a pipe becomes a vent is must ALWAYS be a vent, same is true with a waste line...once a waste line, always a waste line - you can't combine the functions in one pipe except in very special circumatances, and then, only in a bathroom group.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013