3 floors, kitchen sink gurgling on 1st

[Astro46]

1st, 2nd and 3rd floor kitchen sinks, stacked one over the other, seem to drain ok. problem is that that when 3rd floor kitchen sink drains there sometimes is soap foam or minor backup into 1st and 2nd floor kitchen sinks. and gurgling noise from 1st floor sink. i haven't been able to try draining 1st and 2nd floors to see if they cause gurgling on the other floors.

older building, started a month or so ago.

does this sound like a clogged vent problem? or more possibly a clog?

 

[Krow]

Sound like a partial clog in the drain line to me

 

[Sponsor]

 

[Astro46]

Sound like a partial clog in the drain line to me

thanks krow. interesting. i am curious to understand the reasoning, and where you think that the clog might be located.

 

[SewerRatz]

If there is a partial clog after the first floor sink, you can get gurgling when the sinks above that sink are draining.

I get calls for gurgling sinks all the time. I power rod the sink line and flush the line, no more gurgling.

 

[Astro46]

thanks, sewerratz, this is getting more intriguing. i am trying to understand what is going on in there. so, the soap foam and splashing is coming from the churning of water in the trap? how does obstruction below first floor sink cause the churning? is it sort of the opposite of vent problem? instead of trying to pull air from the sink it is forcing air into the sink (air compressing between the flow from 3rd floor and clog)?

splashing in 2nd floor sink could also be from obstruction near 1st floor, or is that likely to be it's own, personal, obstruction?

 

[SewerRatz]

thanks, sewerratz, this is getting more intriguing. i am trying to understand what is going on in there. so, the soap foam and splashing is coming from the churning of water in the trap? how does obstruction below first floor sink cause the churning? is it sort of the opposite of vent problem? instead of trying to pull air from the sink it is forcing air into the sink (air compressing between the flow from 3rd floor and clog)?

splashing in 2nd floor sink could also be from obstruction near 1st floor, or is that likely to be it's own, personal, obstruction?

Second floor sudsing is a partial blockage between the first floor and second floor.

I would power rod from the third floor down, then power rod from the second floor down, and then the first floor down to ensure the whole line is clear.

We do a high rise out in Chicago, their first signs of a blockages is sudsing in the second and third floor sinks. If they wait to long they end up with flooding, so they have us out every 12 months to do preventive rodding for them.

If you had a clogged vent it would siphon out the traps as the water passed by since it needs to draw air. Since the suds are coming up into the sinks that is a sign of a blockage instead.

 

[Astro46]

i'm not disagreeing that it is a blockage, but how come the air doesn't back up into the vent, rather than trying to go through the traps? i am trying to visualize what is happening in the pipes.

 

[hj]

suds

The suds go EVERYWHERE. They are created when the falling soap and water hit the bottom of the riser, where there is probably some obstruction, and "explode" into suds. They do go up the vent, but you cannot see them, but you do see them when they come up in the sinks. The first floor sinks are supposed to be connected to the horizontal drain line, beyond the "suds zone" of the vertical drain to keep it from happening there every time the upper sinks drain, because even the process of the water hitting the bend can create the suds explosion.

 

[Astro46]

The suds go EVERYWHERE. They are created when the falling soap and water hit the bottom of the riser, where there is probably some obstruction, and "explode" into suds. They do go up the vent, but you cannot see them, but you do see them when they come up in the sinks.

Wow. i didn't realize that suds could force themselves through water in the trap.

thanks.

 

[hj]

suds

It is a common problem in high rise structures. One of the challenges with them is to try to slow the velocity of the falling water to minimize problems in the lower levels.

 

[SewerRatz]

Here you go this is some good reading. They talk about designing stack systems with a suds relief offset piping along with relief vents.

http://www.ctaspe.com/docs/techarticles/High Rise Plumbing Design.pdf