# Offset Gridstrainer



## Christina (Jul 14, 2009)

We were called to the hospital for a slow drain, which now has became several drains. Indeed these lavatories are sllllloooooowwwwwww.....

So on this first one:
The trap was removed and a sink machine (3/8" cable) was ran, even though there was no residual water standing in the drain (other than what was in the trap), maybe it was just partially clogged? Reassembled.... still... slow draining!! UGH!! Disassemble the entire Gridstrainer assembly and ensured there was no blockage... hmmm... nothing. Reassembled.... still... slow draining!! UGH!!










Replaced it with just a plain'ole grid strainer and tied back in... NO PROBLEM!!

Anyone else seen this? It is not a one time occurance, this has happened with SEVERAL lavs on a new branch of the hospital. Just Curious. :turned:

Thanks, Christina


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## luv2plumb (Apr 30, 2010)

I have installed offset gridstrainers in the past and haven't had issues with them. "knock on wood"


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## Christina (Jul 14, 2009)

luv2plumb said:


> I have installed offset gridstrainers in the past and haven't had issues with them. "knock on wood"


luv3plumb, I have seen them used in several commercial applications and work just fine...
:blink: Who knows... but I know replacing the offset gridstrainer on all of these has fixed the problem. 

I know... it is the 'union plumbers' that installed it!! J/K :jester:


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## luv2plumb (Apr 30, 2010)

Christina said:


> luv3plumb, I have seen them used in several commercial applications and work just fine...
> :blink: Who knows... but I know replacing the offset gridstrainer on all of these has fixed the problem.
> 
> *I know... it is the 'union plumbers' that installed it!! J/K* :jester:


Careful you might open up a can of worms with that....:laughing:


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## ranman (Jan 24, 2010)

i have them to drain slow also. especially when the sink does not have a overflow


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## mongo (Jun 26, 2010)

It's been about 15 years since I had installed some of those, if my memory serves me correctly they did seem slower than a non-offset drain. We now simply wrap the trap for ADA lavatories to avoid the elongated lavatories w/ offset grid drain. They are still lurking in some engineers drawings and may required again. The elongated lavatories also required fixture supports (carriers).


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## Protech (Sep 22, 2008)

The grid strainer just needs the holes drilled out a bit bigger.


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## rocksteady (Oct 8, 2008)

It's probably a clogged vent. :whistling2:










Paul


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## Redwood (Sep 8, 2008)

rocksteady said:


> It's probably a clogged vent. :whistling2:
> 
> Paul


:laughing::laughing::laughing:
*Troublemaker!*
:laughing::laughing::laughing:

Seriously Protech hit the nail on the head!:thumbup:

Drill out the grid holes as large as you can without trashing the grid and it will drain as good as it can.

Air is caught between the grid and the trap seal when water goes over the grid creates a situation similar to double trapping a line.

Add in another property that water has called surface tension and between the 2 you have a slow draining grid drain...


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## spudwrench (Sep 15, 2009)

Are the traps 1 1/2"? If so I will share my secret. If not, sorry your on your own.


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## Christina (Jul 14, 2009)

spudwrench said:


> Are the traps 1 1/2"? If so I will share my secret. If not, sorry your on your own.


No, they are not.


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## Richard Hilliard (Apr 10, 2010)

*offset gridstrainer*

Absolutely spot on protech.


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## PLUMBER_BILL (Oct 23, 2009)

Christina said:


> No, they are not.


I have seen this problem quite a few times over the years. It not only happens with grid strainers, but with regular pop-up drains also.

I call it the umbrella of air. When the faucet stream hits the drain just right the water will form the umbrella and the water just keeps getting deeper & deeper. The fix -- slow down the water, change the aireator to a swivel type redirect the flow away from the drain. To find out if you are encountering the umbrella take a soda straw and stick it through the strainer and just a bit down into the drain usually the drain goes schloop!
[for lack of a better word].


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## Optimus Primer (May 20, 2009)

usually on commercial we have to install .5 gpm aerators so it's not an issue.


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## markb (Jun 11, 2009)

house plumber said:


> usually on commercial we have to install .5 gpm aerators so it's not an issue.


A little overkill, don't you think? So much for filling up the office coffee maker quickly.:blink:


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## Optimus Primer (May 20, 2009)

markb said:


> A little overkill, don't you think? So much for filling up the office coffee maker quickly.:blink:


 
I didn't come up with the idea of installing them. Call Hillsborough County and yell at them.


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## spudwrench (Sep 15, 2009)

I believe that in our state ( which by the way has passed California as having the biggest deficit in the US), that any ADA faucet requires a .5 GPM faucet. We know how to save water, but money?


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## GREENPLUM (Jul 27, 2008)

why is it that a handicapped person can only have .5gpm of water. It makes it harder for the to wash there hands.


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## markb (Jun 11, 2009)

GREENPLUM said:


> why is it that a handicapped person can only have .5gpm of water. It makes it harder for the to wash there hands.


Handicap people get handicapped sinks :blink:...but more comfortable toilets :thumbsup:


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## ranman (Jan 24, 2010)

but then you can see brass in the holes. been there done that. the gc saw it




Protech said:


> The grid strainer just needs the holes drilled out a bit bigger.


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## Protech (Sep 22, 2008)

Then you have to buy a more course strainer.



ranman said:


> but then you can see brass in the holes. been there done that. the gc saw it


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## ranman (Jan 24, 2010)

Lol 




protech said:


> then you have to buy a more course strainer.


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## plumber666 (Sep 19, 2010)

Trap arm grade good? I've put in lots of these, and usually with a "Marvelle" comp adapter into a tapped cast iron TY. They're often a pain to get grade onto without a leak, so I've seen lots of flat drains. Also, the big wall hung sinks will settle huge without the right carrier/backing, and that can give you backgrade. Seen lots of them drain slow, not any of my installs though, of course....:whistling2:


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