Garbage disposal too low

[Edvs]

Just installed a new kitchen sink, deeper than the previous one. I have an Insinkerator Excel Garbage disposal, and outlet is now about 1/4" too low relative to the ptrap weir and wall stubout. Issue could be solved with a shorter sink flange, since there appears to be about 3/4 to 1" vertical space used by the standard flange. Is such a shorter flange available? If not, will the 1/4" too low cause any problems? I assume there would be some small amount of water left in the disposal. Is this a problem?

 

[Reach4]

Are you saying that the center of the disposal outlet is lower than the center of the trap adapter at the wall?

Is this a problem?

Yes.

To be sure of your measurements, I suggest a self-leveling laser level. Then take a photo that includes the output of the disposal, and the trap adapter at the wall. Here is a situation where the owner thought the trap adapter may have been too low, but it turns out it was not.

 

[Sponsor]

 

[Edvs]

I don't have a laser level.... but picture is attached. It is difficult to see, but the bottom of the horizontal part of the disposal outlet is about 1/8" below the bottom of the horizontal pipe coming from the wall. I therefore suspect that a small amount of water may remain in the disposal. I'll take a chance and leave it as is. The worst that could happen is premature rusting of the disposal? If that happens, I'll replace it with an Insinkerator Evolution Compact or 880LT, both of which raise the outlet by 11/16" compared to the Excel.

 

[wwhitney]

What's the height difference between the bottom of the wall pipe and the bottom of the trap? Trap seal depth is limited to 4", although I recall if that measurement is to the bottom of the water column, or the top of the internal pipe diameter at the bottom of the u-bend.

Looks like you could cut the black discharge elbow shorter to reduce your trap seal depth if required. Switching to a different disposer or lowering the plumbing in the wall is the proper long term solution.

Cheers, Wayne

 

[Edvs]

Yea, seal depth is currently at 5.2". I plan to shorten that by 1.25"+ by cutting the discharge elbow as you suggested. That will get the seal depth within 4". Lowering the wall plumbing is not an option.

 

[Terry]

Dearborn makes a trap that can be reversed. I wish there were better ones out there, as the drain from the wall is too high for the disposer is becoming a real issue with the new 10" deep sinks.

 

[Edvs]

On the P9703W, if the trap is installed reversed (positioned as shown above), what is the seal distance? What makes this j-bend reversible, and not most other j-bends? Thanks for the info.

 

[Terry]

On the P9703W, if the trap is installed reversed (positioned as shown above), what is the seal distance? What makes this j-bend reversible, and not most other j-bends? Thanks for the info.

The J bend allows for a pipe to be inserted. Most p-traps don't have that option.
The seal is deeper than what I would like, but at least it's an option that works.
I would love it if they came up with something better.

 

[Tuttles Revenge]

No matter what is done to modify the trap, the stub out of the wall is higher than the outlet of the disposer which will create a pool of water always in the disposer. I don't know if it will have any detrimental effects on the disposer itself. but I don't think you will be able to fully clear it all the time.

I'm not aware of any shallower flanges. But extended flanges are simply welded on sections. So perhaps someone that is skilled in fabricating stainless steel could shorten that piece the needed amount.