Dishwasher/Garbage Disposal + Plumbing

AZLambdaK1

Hi,

I searched and didn't really find anything specific to my needs.

The previous owners took all the appliances with them, so I had to install my own dishwasher (or have a gaping hole in the kitchen). They left the dishwasher disposal tube and water supply line, but I got new ones. It wasn't vented before, and I had to cut a hole into the cast iron sink to put a vent for it, since I also added a garbage disposal. The previous basket drains were so corroded that they broke as I was trying to remove them, so I had to use a sawzall to cut the lock nut just to remove it. From that, you can probably guess that all the piping going to the drain was also just as nasty.

The dishwasher came with a disposal line that was really long. So long, that I can loop it before connecting it to the vent. Question #1: Is this too long? It's roughly 24 inches more than I really need. Should I get a shorter one?

I live in SF, so metal piping is a must. The garbage disposal says I have to use one of the PVC outlets in order to maintain the warranty. Question #2: Can I just connect the PVC to a T Joint, or do I need a certain type of metal for this?

Question #3: How much slack should there be (if any) between the vent to the garbage disposal? I can probably cut about 4 inches to have a taught line from the vent to the disposal.

Thanks a million. Everyone on here is always a great help!

Mike Swearingen

Don't cut the dw drain hose off. Loop the dw drain hose over the dw to the air gap, and then connect the drain hose to the dw connection on the disposal. Do not forget to take a hammer and screwdriver and tap out the knock-out plug down in the disposal unit before attaching the dw hose with clamps to it.
Good Luck!
Mike

AllanJ

You cut a hole in the bottom of your antique cast iron sink? That don't look good to me.

It is okay to insert the end of the dishwasher drain hose into the upright dishwasher drain tube down under the sink provided the fit is loose.

The dishwasher drain stub on a garbage disposal is intended to have the dishwasher drain hose fastened tightly as the innards of the disposal and sink drain provide the needed air buffer (venting) avoiding overload of the dishwasher drain pump.

Venting for the sink itself is to be accomplished past the trap.

__________________
The disadvantages of crab apple trees. In summer, the apples are too sour to pick and eat. In winter the birds come and leave dropping all over the place.

Alan

X2 on this...

I can't speak for codes other than UPC, but we are not required to use an above-counter airgap for dishwashers (that is by the way an airgap, NOT a vent)

Around here ,securing the dishwasher line at one high point to the countertop is sufficient protection.

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Journeyman Plumber

AZLambdaK1

I wouldn't call it "antique," more like just old. The house was built in the 1920's, and the sink looks like it was installed in the 70's. The previous owners didn't really take care of things, either. Like I had mentioned, the basket drains were too corroded to even remove normally. The sink has all kinds of garbage (maybe paint?) stuck to it. I used a scraper and went at it for a good hour, and most of it's off now.

When the previous owners installed the dishwasher, they literally cut out cabinets. Eventually, I plan on redoing the kitchen completely, since everything seems to have been done "just enough." There are still dead pipes sticking out underneath the sink!

Anywho. The way I connected everything, the dishwasher waste line loops (the loop is hung underneath the counter by the air gap), then connects to the air gap. The air gap then goes into the garbage disposal (yes, I already knocked out the covering in there).

So there should be no issues with such a long tube from the dishwasher to the air gap?

drtbk4ever

I think the instructions with my dishwasher suggested have the drain do a loop.

__________________
Bill

A DIY Noob that knows just enough to be dangerous.