Dishwasher Drain Plumbing Question

[NiceGuyEddie]

156538156539

To the left is the sink cabinet. The drain and garbage disposal is offset to the right of the sink and as shown, the dishwasher cabinet is to the right of the sink.

Despite reading the installation manual and despite watching at least a dozen YouTube videos, for the life of me I can't figure out if I am supposed to buy another dishwasher drain tube and connect it to the factory one, or if I am to unwind it and connect it directly to the disposal.

I am not using an air vent, they are out of code for my area.

I do understand there needs to be a loop or "U" in the drain tube higher than the connection to the disposal.

The drain tube does not come off the dishwasher particularly easily, but it does come off.

What's more confusing is the shortest dishwasher extension tube they seem to sell is 6' long, and that's a lot of extra tubing.

[ydousurf]

NGE, when I installed my new dishwasher, it was on the left side of the double-kitchen-sink and my dishwasher drain tube wouldn't reach the disposal. So I just connected the end of the original dishwasher drain tube to a 3/4" to 1" (elbow for my setup, avoid any 90* angles if possible) and then that connected to a 1" reinforced clear tubing (so I could monitor it from time-to-time) and connected the 1" tubing to the disposal. Now, by having my plumbing go up to 1", the dishwasher flows more evenly into the disposal and not under as much pressure as it would coming from just the dishwasher drain tube, for which it did on my old dishwasher and would spray all over the place. Hopefully that made sense?

Anyway, YES! You can connect the dishwasher drain tube directly to the disposal. I could get a photo if needed, but since your dishwasher is on the right, you should have no issues connecting directly to the disposal. All the best and here's to no leaks!!!

[JohnK]

Here's how ours is connected (Bosch, in case it matters). There's no air gap. The dishwasher drain tube (the white corrugated tube) goes directly into the side of the garbage disposal, with a "U" secured to the back wall of the cabinet.


https://thefactoryfiveforum.com/attachment.php?attachmentid=156540&d=1637257427

[NiceGuyEddie]

Yes, it's a Bosch. For some strange reason "Custom Front Panel Ready" dishwashers are much more expensive than regular dishwashers, but that's another story.

What made this MORE confusing is the rubber end of the tube off the dishwasher fits perfectly to the spout on the dispsosal.

To push in the dishwasher and connect the drain, I will need more of a 12" slot rather than a hole in the cabinet.

Now that we are on the subject, why is there no longer the need for and/or why is the air gap out of code? With my old dishwasher, every now and then it would "burp" and some of the drainage would come out the air gap and into the sink.

[JohnK]

I can't tell you exactly why air gaps aren't needed any more, but AFAIK no modern dishwasher needs an air gap. You're lucky that your jurisdiction has caught up with the times. Up here in the Bay Area they are still required. When we remodeled, we had to install a "faux" air gap on the countertop to appease the inspector (it wasn't connected). After sign-off we removed it and replaced it with a built-in soap dispenser. I hate when arcane code requirements force you to have to do stupid S&*%.

I'm not understanding why you need to cut a slot. Can't you just detach the hose from all the brackets on the dishwasher so it's just hanging loose and feed it through a hole as you push the dishwasher into its cabinet?

[NiceGuyEddie]

Once the countertop is installed, there is very little room to stick my arm inside and push the drain tube through the hole in the cabinet wall. A 12" slot will help a lot.

My guess is modern dishwashers drain more smoothly so you don't need the air gap. Also, a few times the slot in the air gap cover was pointed the wrong way, and it dumped waste water all over the cabinet and floor, not into the sink.

[JohnK]

Are you planning to leave the hose clipped in to the upper hook on the side of the dishwasher? If so, I can see that it would be too short to get it started through a hole. If you unclip the hose from that upper hook as well as the lower grey hook then it should be plenty long enough to get it started through a hole, and then just pull the hose from the sink cabinet side as you work the dishwasher into its cabinet. Either way will work. Leaving the hose clipped in to the dishwasher as shown in your photo has the benefit of not having to fasten it to the back of the sink cabinet to form a "U".

Edit: Yes, I think everyone has had that wonderful experience at least once where the air gap has puked dish water all over the counter and floor. That, and the fact that they're always making gurgling noises, is why they're just a dumb, outdated requirement.

[NiceGuyEddie]

156552

John - I bet you are right! The red line is the bottom of the sink - a very deep one. The orange is the approximate disposal location and the star is the approximate dishwasher connection. If I re-route the drain tube on the clips I will probably be OK.

I think the highest point will be high enough, and there is still a generous "U" at the bottom of the dishwasher.

[mikeinatlanta]

No offense, but Bosch install instructions are pretty clear on this. If you need the length then remove from the brackets as needed. This includes length needed to do the high spot inside the cabinet (33" minimum above the floor). Don't forget to take out the disposal plug before installing the hose.
Edit: You most likely will need the cabinet hole down low with the hose out of the brackets, then clamped up high next to the sink.. This will make for an easy removal and replacement later.
Edit #2: On many Boschs, that grey plastic piece is made to be removed and serve as a hose bracket in the sink cabinet.

[NiceGuyEddie]

No offense, but Bosch install instructions are pretty clear on this

No offense taken, the BOSCH instructions were hybrid IKEA instructions and they weren't clear at all, and this includes how to attach the dishwasher to the countertop or side walls.

I double-checked, and there was no mention about possibly removing the grey plastic bracket, but it's good to know.

[NiceGuyEddie]

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Thanks for all the help - the dishwasher tube (no extension) had to be fished through with a string but it takes a nice turn up top and down to the disposal. With a test run I learned the dishwasher drains in spurts and not one continuous discharge. This might explain why there is no longer a need for the countertop-mounted aerator.

I had a slab leak years ago (sucked) and pictured is an instant hot water heater. I hooked up a power strip because I am not at this house sometimes for a week at a time. The disposal switch is an air-powered switch that temporarily switches off the hot water heater so as to not overload the circuit. (It's probably OK but it came that way so no reason to not use it.)

The blow-off valve is plumbed to the outside of the house with a garden hose. The manual says to drain the unit once a year.

If I were to do it again, I'm not sure I'd do the LED lights that automatically go on when you open the doors, but then again, they sure are slick!

;)

[first time builder]

Looks good Cabinets and all !
Kenny