3rd Floor Kitchen Sink Draining into 2nd Floor Sink. HELP!
I have a plumbing problem...
My 3-family home has three vertically stacked kitchens. All three kitchens share the same drain line that vents through the roof. The 2nd floor called and told me that the kitchen sink was clogged. I went with my Liquid Plumber and plunger. After letting the gel sit for 15 minutes and plunging away, I didn't made any success. I went to the 3rd floor and turned on the hot water to see if the drain worked up there. It was draining fine.
I went back down to the 2nd floor, and the sink was full of hot water from the 3rd floor. I went back up to the 3rd floor and turned on the water again. Leaving it on, I went to the 2nd floor and checked the sink. I could see water flowing upwards from both of the drains, along with some black crud from the walls of the pipes.
The first floor (my kitchen sink) drains perfectly fine.
Here in RI, the temp has been below freezing for a few nights now; is it possible that I have a frozen drain pipe? I'm guessing the blockage (whatever it is) is somewhere below where the 2nd floor drain tee's in on the vertical stretch hidden in the wall (which happens to be an outside wall on the back of the house) that also extends through the roof as a vent at the very top.