# Vessel sink hates hot water!!!



## drsplumbing (Nov 20, 2009)

Howdy guys, 
So here is a new one for me. Repaired a trap for a customer under his vessel sink and he complained it was slow when he shaved. 

I fired up the small snake and cleaned her out without hitting anything at all in 15 feet. Put it all back together and ran the cold water. Drained with a spiral for as long as the water was on.

As soon as I swich it to hot water it slows, starts to fill the bowl. As soon as I cup my hand and make a little suction pressure it drains down.

It is properly traped and vented with the tailpiece about 10 inches long below the grid strainer.

I know for a fact there is zero clog. I can literally run the cold indefinitely. As soon as I go to hot she slows down.

Im a big fan of science and I'm 100% sure it has to do with the physics of the hot water. I just can't find any info and I figured one of my brothers in arms would have an idea..

My theory is because it is a vessel sink with a grid strainer with no overflow the hot water for some reason will not let the air flow in the tail piece. 

I'm going to try and put a straw in the middle of the grid strainer and test my theory.

I'd love to hear what you think!!!

Dave


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## plumberkc (Jun 23, 2011)

I've had the same issue but never narrowed it down to just hot water. Curious to see if anybody has a helpful reply.


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## SchmitzPlumbing (May 5, 2014)

i would install a different style grid strainer or a pop-up with the lever pointed towards you. some grid strainers drain bad. its like they air lock sometimes.


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## dhal22 (Jul 30, 2010)

I hate vessel sinks due to airlock problems.


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## Redwood (Sep 8, 2008)

The water over the poorly designed grid strainer with the holes too small acts just like double trapping a drain...

I wrote this article about it on my website...


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## Debo22 (Feb 15, 2015)

Grid strainers vapor lock, it's probably only showing up on the hot side because there's more water volume, cold angle stop is allowing less water through.


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## drsplumbing (Nov 20, 2009)

Exact same flow rate hot and cold... The crazy thing is if I fill the bowl with hot and dump a cup of cold in it she spirals down. Deffintly something with vapor lock and maybe the hot water for what ever reason has an effect on it....


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## dhal22 (Jul 30, 2010)

drsplumbing said:


> Exact same flow rate hot and cold... The crazy thing is if I fill the bowl with hot and dump a cup of cold in it she spirals down. Deffintly something with vapor lock and maybe the hot water for what ever reason has an effect on it....


interesting for sure.


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## dhal22 (Jul 30, 2010)

Years ago I had a customer so upset with HIS vessel sink performance (my fault of course) that I tapped the back of threaded tailpiece, threaded in a 1/4" thread x 1/4 comp fitting, anchored it with JB Weld and installed 1/4" copper tubing from the tap through the back of the cabinet and up into the wall (above flood rim level). It worked like a charm. I still service that house occasionally and chuckle about my less than professional solution. It is still there.


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## Redwood (Sep 8, 2008)

Taking a drill and carefully drilling the holes larger will often fix the problem, as will replacing the grid strainer drain with a lift and turn drain...


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## dhal22 (Jul 30, 2010)

Correct on lift and turn.


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