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Discussion Starter · #1 ·
My bathroom sink drains slow. The one on the other side of the wall does not and it drops into the vertical stack at a double wye with the first one. I've cleaned the trap so there must be a small block between the trap and wye.

Here's the thermodynamic question: When I fill the sink with hot water (to shave) is drains slowly. As soon as I run cold water (denser sinks to bottom of sink and into drain) it starts draining faster. I think it is something in the clog that expands with heat, contracts with cold. Any other ideas scientists?
 

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The cold water could possibly cause a clog to contract small amounts to allow the water to pass more quickly. I seriously doubt that it would be a visible difference.
 

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Try cleaning the vent from the roof top.
 

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I have to periodically stick a hooked stiff wire down our drains b/c hair and crap get caught at the stopper mechanisms and slowly get's bigger and choke's them off.. No biggie, but still a pain..

ANd acid or Draino won't fix this b/c the trap is lower down...

pdq67
Yeah, I have to take my stopper out about every 6 months or so.
 

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Architect,

you need a plumber...LOL

Seriously, take apart the p-trap and wall bend, see if there are obstructions or something in the bottom of the trap.

if it's clear...we'll move on to the next question, then get back to me.

Greg
 

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Discussion Starter · #9 ·
Architect,

you need a plumber...LOL

Seriously, take apart the p-trap and wall bend, see if there are obstructions or something in the bottom of the trap.

if it's clear...we'll move on to the next question, then get back to me.

Greg
I'm not worried about how to fix it , I got that covered just the oddity of the cold water making the water run out. I've cleaned the trap, it was full of hair and other gunk. Pipe to the waste/vent wye is a straight shot.

I grew up in a house with inadequate cleanouts, etc. and we were always involved in "home plumbing projects" what involved me as the smallest person available crawling into the restricted space and getting covered in poop and other fluids.

When I rebuilt the plumbing in this place 20 years ago I put in plenty of cleanouts and straight runs. All straight runs are accessible for snaking. I also over sized the piping 2" vs 1.5, 4 vs 3, etc. which seems to have helped. Except for this one pipe I've had no problems.

Thanks for the help. BTW I'm not a big fan of putting Draino, etc. down the pipes.
 

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Yeah, sometimes it doesn't pay to be the smallest guy.

More cleanouts are always a good idea. (off subject) Oversizing is ok but by oversizing the pipe you also slow the velocity.

And I agree, Drain-o is a last resort.

Just curious, Are the wye's stacked on top of each other and are they vented?

Can't be too many architects in Id. Let alone doing their own plumbing. LOL
 

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As you probably know that the pressure at the drain is derived from the wieght of the water volume above it, which is related to the density. You already stated that the denser (cooler) water heads to the bottom, so now any sample of water taken vertically will weigh greater than before the cool water was added, essentually creating greater pressure at the bottom, in turn increasing the velocity of the fluid through the drain. This probably does not account for much change in velocity... This probably happens faster than the clog heating up and contracting..I don't know
 

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Discussion Starter · #12 ·
Just curious, Are the wye's stacked on top of each other and are they vented?

Can't be too many architects in Id. Let alone doing their own plumbing. LOL
There are two lavs back to back into a double wye into the waste & vent. Waste is 2", vent is 1.5". Other sink is fine. There are a bunch of architects in Idaho, not many do their own building. I come from 5+ generations of master journeyman carpenters and builders, I was the first to go to college in my family. As in most states homeowners in Idaho can do their own electrical and plumbing work (except for gas piping) and it has to be inspected. If inspector does not like the quality of work or thinks you do not know what you are doing he can require an electrician or plumber inspect and finish the work. My work was inspected and passed.

Chevelle68 I hadn't thought of the added weight but that might be the difference, pushing past the partial obstruction. Thanks guys Patrick
 
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