Cold Water Drains, Hot Water Backs up? Huh?

[Sirdeaver]

Hi All!

I'm looking for someone to explain this behavior in a new sink just installed in our bathroom. Cold water will drain all day, no issue. Turn it to hot, and it starts slowing backing up. I can hear some of it still gurgling down the drain, but obviously not enough to keep up. Turn the water back to cold, and it will start draining just fine again. What the heck is causing it?? Drain with the push button stopper shown below.

 

[James Henry]

The hot water is probably expanding the gasket.

 

[Sponsor]

 

[Sirdeaver]

The hot water is probably expanding the gasket.

But the one gasket is on the outside of the drain fixture - no interference with the water that runs through the middle. And the push button gasket, the one that blocks the water when you push down the middle, is at the top of the openings and out of the way - so would not seem like that would do it either.

OK. Ran across this thread...

https://terrylove.com/forums/index.php?threads/hot-water-doesnt-drain.33233/

... which seems to answer the question. Basically, Vapor Lock due to the lack of an overflow. Weird. Terry points to a drain fixture designed specifically for vessel sinks as a solution near the bottom of the thread. Thanks!