Disposal Draining Options-- 2 Traps?

dzd9fy

dzd9fy

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I am having a problem with the disposal on our double sink, in that water is forced up the drain of the second sink when the disposal is run. Not a great amount, but enough that it is unsightly and makes my wife unhappy.

I have tried the end drain design as shown on this sight, [htp://www.terrylove.com/wwwboard/messages2/24587.html] and have not seen much relief, probably due in part to the height of the drain to the stack in the wall. I only have a 1" drop from the center line of the disposal drain to the center line of the drain line. The other sink has a 4" drop to the center line of the drain line. So neither sink or disposal are draining up hill.

My question is, can two traps be plumbed in to resolve the issue? Both would still go to the same drain line and still allow for gravity to do its work. I am sure this would take more space under the sink, but that is less of a concern than the current condition. Thanks!
 
Are you using a baffle tee"
They have a partition that splits the sides, forcing the water down the drain, not allowing it to go up.
 
Are there different styles of baffle tees? The drain was originally set up with a center drain and that is the tee I reused in the end drain position.

Hopefully it is as simple as a trip to the local supply house for a different tee? :)

The drain is clear, and the vent is common with the adjoining bathroom and no issues there. Thanks
 
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dzd9fy said:
Are there different styles of baffle tees? The drain was originally set up with a center drain and that is the tee I reused in the end drain position.
Click to expand...

That would be the problem, You had to turn the T will the baffle sideways, if I follow you, I'm not sure how you did that maybe it was a compression T no baffle. All three sides must have been compression. By the correct drain crossover kit for an end outlet drain and change it. Here's a link with a picture of the set up

I did work for an old plumber once that wanted separate traps for each sink and the dishwasher separately. He didn't like the idea of any crossover, maybe he was right, maybe not. He thought it was unsanitary to take the chance of dishwasher water getting into the sink or disposal garbage crossing over like you have. With the correct setup it shouldn't happen IMO. I have seen many houses with two traps for a double sink and a stand pipe and air gap for the dishwasher.
 
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If you use more than one p-trap, it should be plumbed for it in the wall, all properly vented.
Code does not allow for more than one p-trap on a trap arm.

When you see two traps, you normally see two stubouts from the wall, and behind the wall, a fixture cross with a vent in the middle.

An example of an illegal S vent. These were outlawed before I even started plumbing in the 70's
It's not vented properly.
The trap arm should go out horizontally, and be vented at that point, not below the floor and the trap. This one will siphon itself dry.
 
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Terry said:
If you use more than one p-trap, it should be plumbed for it in the wall, all properly vented.
Code does not allow for more than one p-trap on a trap arm.

When you see two traps, you normally see two stubouts from the wall, and behind the wall, a fixture cross with a vent in the middle.
Click to expand...

Correct, except I have seen some monsters plumbed after the fact using AAV's. I like and use crossovers, personally I see nothing wrong with them, until ICC says I should see something wrong with them.

I didn't pay attention to the S trap, just the crossover, sorry, good catch. You'll have to crop that for me.
 
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Terry, what kind of cross over would you use T or Y. I don't like T crossovers except venting, but the Y tends to break the vent, I know code allows it on short runs for small pipes, but I tend to want to revent after the rise, overkill? Do you use two inch to upsize or stick with 1 1/2" if you do it for a kitchen sink with two traps or if you did it? Like I said on a kitchen sink I use the crossover under the cabinet one trap, if I did what would you do?

And where can I read how to do the picture thing?
 
OK I think I have the picture thing figured out under manage attachments button. From the FAQ section, I guess I should learn to read instructions, but hey I'm a remodeler.
 
This
Wye%2045%20Double%20HxHxHxH%20DWV.jpg


Or this

Cross%20HxHxHxH%20DWV.jpg


The sanitary one.

For behind the wall two trap set up proper vent.

Maybe I should have said double wye and double tee.
 
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Would that be Ok on some of the kitchens with large windows as far as keeping the vent vertical until the rim of the fixture. Even with 45's you hit the window before you can clear it, so treat the big window as an Island situation?

I thought the clean out was on the vent side of the down pipe.
 
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With a large window, I go as high as I can, (below the nails) and then turn horizontal with the vent, using sweep 90 els below the flood level of the sink.

There has to be a cleanout on the sink waste.
This CO can be snake both directions.

There is another cleanout where the foot vent comes up in another wall.

sink_dw.jpg
 
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Terry said:
With a large window, I go as high as I can, (below the nails) and then turn horizontal with the vent, using sweep 90 els below the flood level of the sink.
Click to expand...

That would vent better than the island venting IMO. I'll have to check with our inspector, but I don't see why that wouldn't pass if an AAV under the counter will. I've done it that way too, but never had to have it inspected. I'll tell them you do it that way.
 
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