Bigcaliber
Member
I'll be as brief as I can...One of the buildings I do maintenance in has a slow draining sink in the restroom. The men's restroom is back to back with the ladies rr. On the common wall are 3 sinks in a row on each side of the wall. My most immediate puzzle is the center and right side sinks in the men's room. The one on the left drains just fine. The one in the center is "slow", and the sink on the right is very slow. I pulled the P traps from all 3 and found them clear. I ran a snake gun into the wall at each sink to the clean-out, which is between the left and center sinks. Though I could not remove the clean-out plug, I know the drain, (or is it waste line?), is clear because the left drain works flawlessly. Now, (here it comes), when I stop up the drains of the other 2 sinks, and fill them to just below the overflow hole, the water will drain like the devil's chasing it. But run the water normally and they drain slow. I tried putting a hose down the vent on the roof but that nothing. In the attic, the vent pipe drops down from the roof approx. 10-12 feet to a tee. The lines from the tee go out roughly 6' where they then go into that common wall. There is a 3rd line that tee's into one of the 6' lines and goes down. On the ladies side, the sink on the right also drains slow. But it is directly across from the men's sink on the left side which drains fine. I know there is some sort of siphoning effect going on, but I have no clue as to what, how, why, or where. Any thoughts would be greatly appreciated.