I have been busting myself recently trying to get my basement reno finished. It is getting very much into the home stretch. Last night was not a good night for work. I am currently working on about 4 hours of sleep due to a very strange problem.
I was attempting to install a sink in the bathroom, one of the new vessel style sinks:
Pretty straight forward. So everything got hooked up. One problem… It wouldn’t drain?!?! I was terrified. The last thing I wanted to be doing was to start tearing apart walls looking for a clog. As a test I pulled the clean out on the P-Trap and it flowed no problem. Ugh Oh!
A few more tests. Filled up the sink a few more times. It would drain well for a bit, then it would slow to a stop part way down. Every few times that I tested it, there would be an air bubble then it would drain all the way down. Crap. Is there an high spot and an air lock in the wall? That would be bad. So I took the sink off and poured water directly into the P-Trap. Drained perfectly… So the problem was with the sink? I checked the drain to make sure there was no blocks. It was really easy to check. I have a grid style drain so I could look and blow straight through it.
Grid Style Drain:
I was completely stumped. It seemed like the water was just dripping into the P-Trap. And I pretty much knew that the problem was between the sink and the trap.
I did a quick internet search. What did I find? All kinds of problem with grid style drains and vessel style sinks. The best explanation was this one:
The problem the OP is experiencing is due to the combination of a grid drain and a sink with no overflow. In order for the sink to drain properly, water must displace the air in the drain pipe going to the trap. In sinks with an overflow, the overflow acts as a vent allowing air to escape the drain pipe as water pours into the pipe through the drain.Without an overflow, the air in the pipe must escape through the same drain that the water is using. That is why you will see air bubbles coming up through the holes in the grid. Grid drains make the situation worse – probably due to the surface tension of the water interacting with the little holes in the grid to basically form little seals. Also grid drains tend to have less aperture area than umbrella valves. The more area the easier it is for the water and air to share the same drain.
Sure enough sticking my hand in the water and spinning it (creating a vortex) caused it to drain perfectly. Alanna bought a new drain as per the recommendation from this forum post: http://www.askmehelpdesk.com/plumbing/new-non-vented-sink-vanity-install-drains-slow-253882.html.
Regardless I am exhausted, frustrated, and a little pissed that the drain that came with my sink doesn’t work.
On a happier sink note: