Undersink plumbing

[masraum]

I've done a ton of this sort of work in the past, but that was on my own house. Now this is an apt.

The apt comes with a sink that is split, but it's like a 80/20 split, tiny sink on one side and much larger, deeper sink on the other side. For whatever reason, they put the disposal on the small side which is a huge pain. I'd like to swap things around. The pipe that comes into the back of the cabinet curves away from the disposal. What would be the easiest way to reroute down here that would enable me to swap the disposal to the other sink? Is there anything specific that I'd need to keep in mind with the routing?

[wdfifteen]

Will there be enough fall between the disposal outlet and the pipe in the wall after you lower the disposal?

[john70t]

I ain't an expert, but it might not be do-able with that sink and/or without modifying the main stack attachment height.

1). Look at the basin heights.
The big one sits much lower.

2). Look at the vertical distances: Compare the disposal top with its output port to where it will end up via the wall exit pipe.
It has to be higher than the wall exit for it to drain at all.

When entering the vapor/p-trap, there needs to be some gravity acceleration for the water to push all the food particles through the bend and flush it through.
With the disposal output directly above the p-trap, that won't happen easily.
Water will be able to sit in the pipes, on the joint lines, and eventually will leak out inside the wood cabinet.

[look 171]

reverse the install. Make sure the bottom of the interior is higher then the pipe comiing out of the back or drain.

[Christien]

Why would you reverse them? IMO, the sink+disposal is where you peel carrots or potatoes, clear the dinner plates, dump the chopping garbage from the cutting board. What else is the little sink good for, other than a basin for water to wash that stuff down the disposal? If you were to swap them, I would think that would render the little sink completely useless.

[dad911]

Originally Posted by john70t

.....
When entering the vapor/p-trap, there needs to be some gravity acceleration for the water to push all the food particles through the bend and flush it through.
With the disposal output directly above the p-trap, that won't happen easily.
......

?? Very often the downturn comes with the disposal, and the trap connects to it directly.

[look 171]

Originally Posted by Christien

Why would you reverse them? IMO, the sink+disposal is where you peel carrots or potatoes, clear the dinner plates, dump the chopping garbage from the cutting board. What else is the little sink good for, other than a basin for water to wash that stuff down the disposal? If you were to swap them, I would think that would render the little sink completely useless.

It may not be him. It just be the supreme commander that wanted it that way. I built lots of custom kitchens over the years, people have different ideas, some are great ideas some not so much, but they are absolutely happy with those decisions.

[john70t]

Originally Posted by dad911

?? Very often the downturn comes with the disposal, and the trap connects to it directly.

The disposal pushes out high velocity waste/water, but against a flat T-connection.
(fwiw-The "bend" in that diagram shows the disposal output pipe stub which is immaterial to flow.)

More important is the p-trap.
It looks like a "U" shape.
It is designed to let the waste water past, then leave a contained layer of fresh water to keep sewer gases from rising back into the house.

In an abandoned house where toilets are not often flushed, water held in the p-traps will eventually evaporate, thus letting city-street-sewer gas back into the house.
-You do not want s**t air pushed into your house from the drains.
-Nor backup liquid effluence filing up bathtubs and spilling across basement floors due to a clogged main.

[intakexhaust]

This just reminded me of that old Steve Martin comedy routine and using a 'gangly wrench'

[JavaBrewer]

Originally Posted by Christien

Why would you reverse them? IMO, the sink+disposal is where you peel carrots or potatoes, clear the dinner plates, dump the chopping garbage from the cutting board. What else is the little sink good for, other than a basin for water to wash that stuff down the disposal? If you were to swap them, I would think that would render the little sink completely useless.

Regardless of the plumbing concerns Christien is 100% correct. That small sink is there for exactly that purpose. Move the disposal and that little sink is now worthless.

I agree with what's already posted. The drain inlet is not low enough for the disposal to sit under the big sink.

[wdfifteen]

Originally Posted by JavaBrewer

The drain inlet is not low enough for the disposal to sit under the big sink.

There might be, it's hard to tell from the perspective of the photograph. A careful measurement is indicated.

Here's how I would do it. Carefully measure to confirm that there is fall between the disposal outlet and the wall. Move disposal. Glue up appropriate piping. Put extra RTV and epoxy on the slip nut connects for extra security. Then cut it all apart and start over after I realize I ran the pipe through the loop in the sprayer hose. YMMV.

[74-911]

Originally Posted by wdfifteen

Here's how I would do it. Carefully measure to confirm that there is fall between the disposal outlet and the wall. Move disposal. Glue up appropriate piping. Put extra RTV and epoxy on the slip nut connects for extra security. Then cut it all apart and start over after I realize I ran the pipe through the loop in the sprayer hose. YMMV.

Based on past experience, My Mileage probably wouldn't Vary unfortunately.... sounds like my kind of plan.

[plumb4u2]

as stated that disposal was put there because that's where it belongs...the small sink is for food prep which is what the disposal is for

if it bugs you for some reason that pic shows me that you have plenty of room to do whatever you like

[GWN7]

Put a second disposal on the big sink. Then it doesn't matter which one you dump the junk into.

[O'Grady]

The disposal should never discharge into the horizontal, it comes with a 90° drop for a reason, the small (prep sink) is the correct location for the the unit.
Most responding here are forgetting how a baffle tee works and how the lager basin is designed to wash the smaller, physics 101?
P.S. Unlike others I am an expert on this.

[craigster59]

Is this for you or a tenant? As a landlord, I've found that tenants and garbage disposals are a bad mix. They think you can put ANYTHING down there.

[masraum]

Originally Posted by wdfifteen

Will there be enough fall between the disposal outlet and the pipe in the wall after you lower the disposal?

Not sure, I think it would be fairly close, but I have not measured. I was thinking that might be a problem, but wasn't sure.

Originally Posted by Christien

Why would you reverse them? IMO, the sink+disposal is where you peel carrots or potatoes, clear the dinner plates, dump the chopping garbage from the cutting board. What else is the little sink good for, other than a basin for water to wash that stuff down the disposal? If you were to swap them, I would think that would render the little sink completely useless.

frankly, the sink as already nearly useless. I think the problem is the faucet. It will put water into that sink, but it's kind of a high velocity water and it often ends up splashing around and making a mess.

Originally Posted by wdfifteen

There might be, it's hard to tell from the perspective of the photograph. A careful measurement is indicated.

Here's how I would do it. Carefully measure to confirm that there is fall between the disposal outlet and the wall. Move disposal. Glue up appropriate piping. Put extra RTV and epoxy on the slip nut connects for extra security. Then cut it all apart and start over after I realize I ran the pipe through the loop in the sprayer hose. YMMV.

I think I've done that before in the old house.

Originally Posted by GWN7

Put a second disposal on the big sink. Then it doesn't matter which one you dump the junk into.

Hah, nice, I like it, but I'm not going to spend money on an apt.

Originally Posted by O'Grady

The disposal should never discharge into the horizontal, it comes with a 90° drop for a reason, the small (prep sink) is the correct location for the the unit.
Most responding here are forgetting how a baffle tee works and how the lager basin is designed to wash the smaller, physics 101?
P.S. Unlike others I am an expert on this.

OK, well, the complex is about 1 year old, so this is how "they" put the place together. So far it seems to work ok for us. The small sink may be more useful if we had a different faucet, but we don't. I think we'll just have to live with it.

Originally Posted by craigster59

Is this for you or a tenant? As a landlord, I've found that tenants and garbage disposals are a bad mix. They think you can put ANYTHING down there.

We are the tenants, and you're right, I've had a heck of a time getting my loose change and broken glass through the thing. it makes a HORRIBLE racket. I have a mind to complain to management!

[onewhippedpuppy]

The better question - how does your landlord feel about you taking it upon yourself to DIY reroute the kitchen drain? I suspect most would frown on that.

[masraum]

Originally Posted by onewhippedpuppy

The better question - how does your landlord feel about you taking it upon yourself to DIY reroute the kitchen drain? I suspect most would frown on that.

What they don't know....

They are actually pretty cool about having stuff changed. They even had some sort of DIY contest recently. Send in pics of what you've done, and win a gift cert or something.

I asked one of the maintenance men about it and he said that some other tenants had asked the same thing, but that it couldn't be changed. Hmm, couldn't be changed, or too big a job for them to tackle? If it weren't for the possible issue of the drain from the disposal being too low, I'd probably do it. Heck, I could always put it back. I suspect I'll just end up leaving it though.

[CHICKS]

It's not your place to move it. Want to change plumbing, buy your own place. This is why I hate tenants....