Suggestions for improving sink/disposal drain

[GaryA]

This is my current sink/disposal drain set-up (see photo). It drains OK and there are no functional problems, but I'd like to do it better. I suspect the trap isn't to code because of the transition from plastic tubular to the larger PVC and then back to the plastic again. I also don't like the center tee arrangement and would rather have an end waste tee. For the trap, a regular plastic p-trap won't work because of the height of the drain. The drain is exactly 1-1/8" lower than the disposal outlet.

I am considering the following options:
1. Get rid of the disposal (but my wife likes it).
2. Cut the trap adapter off of the drain, use a 1-1/2" PVC coupler and a PVC 90 connected to a PVC p-trap. I kind of like this idea. It would fit, and would have about a 3" seal depth.
3. Use a regular plastic p-trap like a Keeney 400PVCK, reversed so it will fit. The seal depth would be about 4", maybe slightly more.

Suggestions, comments, rants?

 

[IFIXH20]

The keeney reversible master trap and a tubular disposal drain kit should work for you if you do not want to open the wall and lower the drain. Trap seal should not be less than 2'' and no more than 4'' for your application.

 

[protech]

Honestly man, if you aren't having any problems with it such as backups or leaks, I wouldn't mess with it.

It's not perfect but if it was in my house I wouldn't mess with it. Just my $0.02

 

[GaryA]

Thanks IFIXH2O, I was hoping to get an answer like yours. After I posted, I did some more research and was leaning towards that solution. It's my understanding that as long as the seal is 2" to 4", this meets code (but I haven't found the actual citation). I believe there are two traps that are designed to be reversible - the Keeney 400PVCK and Dearborn Brass P9703WBG (or P9703BG). They actually look like the same part.

 

[GaryA]

Here's a related question. I'm thinking of using a PVC trap with union (photo 1). I could cut off the existing trap adapter, but I was wondering if I can just remove the nut from the trap adapter and connect a PVC adapter fitting (see photo 4) to it. This would give me more flexibility if it doesn't work out or if I don't like the result. I can't tell if the existing set-up has a trap adapter (see photo 2) or just a regular PVC adapter (see photo 3) with a trap adapter nut and washer. I checked them at HD yesterday and it appears that the "PVC adapter part" of the trap adapter (photo 2) is almost identical to a regular PVC adapter (photo 3). The thread pitch and depth is identical.

 

[GaryA]

Oh, this is bad, I'm answering my own question (but I'm not talking to myself, yet). I found this on another forum:

"The desanco fitting (or trap adapter) has shorter threading and a tapered interior edge to mate with the desanco washer. The male adapter is not tapered on the inside and has a longer thread shank. Both will work as male adapters. A male adapter, on the other hand will NOT work as a desanco without tapering the interior."

 

[GaryA]

Well, upon further inspection it looks like what I thought was a PVC trap adapter is actually a thinner-walled adapter of some sort. It has no markings so I don't know what it is, but it doesn't have the usual markings that you see on a PVC fitting. It actually looks like the trap adapter they sometimes include with a plastic p-trap. So, I'm not sure if the UPC and/or IPC codes would allow putting a female PVC adapter onto it.

Got any ideas on this?

edit: I think the trap adapter is DWV, and not a regular sch40 PVC fitting.

 

[Matt30]

Starting to put way too much thought into a simple sink hook up here

 

[IFIXH20]

Well, upon further inspection it looks like what I thought was a PVC trap adapter is actually a thinner-walled adapter of some sort. It has no markings so I don't know what it is, but it doesn't have the usual markings that you see on a PVC fitting. It actually looks like the trap adapter they sometimes include with a plastic p-trap. So, I'm not sure if the UPC and/or IPC codes would allow putting a female PVC adapter onto it.

Got any ideas on this?

edit: I think the trap adapter is DWV, and not a regular sch40 PVC fitting.

The thinner trap adapter comes in master trap (p-trap) kits, Just away for companies to save a little money. From the look/angle of your photo it seems a standard tubular disposal kit & p-trap (reversible) will work just fine.

 

[GaryA]

Starting to put way too much thought into a simple sink hook up here

Yes, I have a bad habit of doing that.

 

[GaryA]

The thinner trap adapter comes in master trap (p-trap) kits, Just away for companies to save a little money. From the look/angle of your photo it seems a standard tubular disposal kit & p-trap (reversible) will work just fine.

I've got a DBHL P9703BG which is supposed to be reversible, but they've changed the design so it's not a 'U' bend like in some of the photos. Now it's more like a 'J' bend like the non-reversible traps. You can see in the attached photo that the trap depth is exactly 4". Would a reversed j-bend like this drain properly?

And, I have read where the reversible ones may not be to code when reversed, and some inspectors will fail these.

I don't really want to use it if it's questionable.

The second photo is what I'm thinking doing. Cut off the adapter and use all PVC up to the trap adapter.

 

[phishfood]

I would use the first picture. It is a real pain trying to get a 3/8" cable to turn that glued on trap 90, easy peasy through the straight trap adapter.

 

[GaryA]

I would use the first picture. It is a real pain trying to get a 3/8" cable to turn that glued on trap 90, easy peasy through the straight trap adapter.

Thanks for the tip. Actually the trap is a few inches from the wall, so if I go with the PVC solution (photo 2) I'm planning use a female/male coupling in the straight section between the trap and the wall. That way if I mess it up (or something changes), I can just unscrew it and change it out.

 

[GaryA]

OK, here's the final result. I spent half of my Sunday doing this, and missed the Packer Game, but it turned out pretty nice, eh?

It's not too easy to see, but there's a male/female adapter connection just off the waste tee. I put that in just in case my plan didn't work out as well as I thought, so I could just unscrew it and do something else if I needed to. As it turned out, everything worked as I thought. As you can see, I had just barely enough room for the plastic tee (with maybe 1/4" to spare).

Overall drop from the disposer output to the wall tee is about 1-1/8" to 1-1/4". I think with anything less than 1", you would have to go with a different design, or open the wall and lower the waste tee. With a disposer outlet only slightly above the level of the waste tee, you might be able to tee the PVC and use two separate traps, just maybe.

In case you were wondering, there's about 1/4" in 12 slope on the disposer output tube.

 

[Mr_David]

Nice job. Is that a baffle tee?

( funny side note: I had a tool supply store where someone installed a baffle tee upside down, for yrs they had this problem. When they use the disposal it would shoot water up out of the drain. )

does your dish washer drain have an air gap ?
Looks like it comes from high up in the back corner.
If you do I suggest replacing the corrugated hose from the air gap to the disposal with 7/8" neoprene hose. I use 3/4"copper fittings to make any tight turns so you done kink the hose. just a suggestion

otherwise, it looks good

 

[GaryA]

Nice job. Is that a baffle tee?

( funny side note: I had a tool supply store where someone installed a baffle tee upside down, for yrs they had this problem. When they use the disposal it would shoot water up out of the drain. )

does your dish washer drain have an air gap ?
Looks like it comes from high up in the back corner.
If you do I suggest replacing the corrugated hose from the air gap to the disposal with 7/8" neoprene hose. I use 3/4"copper fittings to make any tight turns so you done kink the hose. just a suggestion

otherwise, it looks good

Yes, I it's a baffle tee (I actually checked it to be sure). I would assume that part could only go in one way, but I guess a creative DIYer (or genius hack plumber) could figure out a way to invert it!

It has a high loop, no air gap. The dishwasher drain hose goes all the way to the underside of the counter top, then back down to the disposal. There's a hole in the counter top that is currently occupied by a soap dispenser, but could be used for an air gap if needed.

Thanks for the tip on the dishwasher drain hose. I just used the one that came with the dishwasher kit, but I can see where the corrugated hose could cause gunk to accumulate inside. And, it looks like plastic so is probably not too durable. If I ever put in the air gap, I would probably leave the corrugated hose up to the air gap, then use the neoprene from the air gap down to the disposal.

 

[Zanne]

Looks like you did a good job!
Its nice and clean under there. I like your solution to hold the hose up. Nice little jars and candles under there too. I think I have one like the red candle.