Installing a dishwasher air-gap

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  #1  
Old 03-16-05, 06:57 AM
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Installing a dishwasher air-gap

Hi everyone,
I'm installing a dishwasher and garbage disposal at the same time and I was told to buy an "air-gap" so I did.
The dishwasher and garbage disposal steps are pretty straight forward but I'm a little confused with the air gap part.
If I look at the dishwasher drainage hose, it plugs right into the garbage disposal's outlet (after I punch out the hole). Now maybe I'm looking at this wrong but the air gap piece has two "ports" (not sure what the appropriate term is), a big one (same size as the garbase disposal's outlet) and a smaller one that I'm not sure what is supposed to attach to it.

I thought the air gap is a "go between" located in the middle of the garbage disposal's "dishwasher port" and the dishwasher drain so why are the ports different sizes? I could hook the dishwasher's drain to the air gap (on the big port) but then how would I take connect the small port to the garbage disposal's drain (or vice versa if I ran a drain line from the garbage disposal to the air gap's big port how would I hook the dishwasher's drain to the air gap's small port?)

So my questions, besides "how do you install an air gap" are:
a) Which connects to the big port on the air gap, the garbage disposal's "dishwasher port" or the dishwasher drain?
b) How and to what does the small port on the air gap get connected?
c) (Just out of curiosity) Shouldn't the two ports on the air gap be the same size? and why the reduction?

I have the feeling I'm way off the mark here but I just can't visualize how this air gap's supposed to work,

I'd appreciate being pointed in the right direction,

Thanks a lot,

-MC
 
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Old 03-16-05, 07:17 AM
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One of the "tubes" is the inlet and the other is the outlet. They may be marked. You run the dishwasher to the inlet side and then another hose from the outlet to the disposal.
Did whoever sold you the AirGap say it was code in your area? Some places it is and some not. Asking due to the fact you have to cut a hole in the countertop or sink if one is not already provided.
Check the Air Gap for marks as far as inlet and outlet. Good luck.
 
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Old 03-16-05, 07:34 AM
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I must be dense

sorry I have no idea what inlet and outlet mean (other that one takes drainage in, the other out) but for my purposes which is the "big" one and which is the "small" one? Is the inlet the small one and the outlet the big one?
And if that's the case, how do I plug the big dishwasher drain into the small inlet valve. If it's the reverse, how do I run the small valve out to the garbage disposal?

There is no requirement to have an air gap but someone warned that sewage from the garbage disposal could back up into the dishwasher if I didn't have an air gap which didn't sound too appetizing.
If I could get away without putting that stupid thing in I would, can I?

I already have a hole in the sink that's occupied by a sprayer. I actually want to take out the sprayer since it's so close to the cold water faucet but I don't know how to plug up the area where the sprayer attaches to the faucet?

-MC
 
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Old 03-16-05, 07:44 AM
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It is recommended that Air Gaps be installed. I have NEVER installed one. I always run the dishwasher hose as high as possible over the cabinet wall going to the sink drain and this forms a loop to prevent the dishwasher from being drained while it is running. I have not seen the disposal back up into the dishwasher although it COULD be a possibility. You will have to ask (if not marked on Air Gap), which is inlet and outlet and also get the hose that fits. Sorry I can not be of more help. Someone who has installed one may answer so watch this post.
 
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Old 03-16-05, 02:43 PM
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On a dishwasher air gap the smaller of the two pipes is the inlet of the air gap, the larger pipe is the discharge which leads to a garbage disposal or tapped tailpiece. They are required in some states and not in others. All plumbing code books state at no time there should be a direct connection between any device used to sterilize/clean items used for human use, and the wastewater system. Air gap prevents the continuation of backflow by the free atmosphere. High looping is always under the flood level rim of sink, by the thickness of the sinktop itself, therefore if the kitchen sink clogs, the backup will carry through the high loop before spilling over the edge of the sink.
 
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Old 03-16-05, 03:02 PM
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The word ALL is over used and not always correct. Florida and Ohio do NOT say anything about connecting a dishwasher to a disposal. I did a hotel at Disney World and they went STRICTLY by the book and every one of their disposers are directly hooked to the dishwasher.
 
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Old 03-16-05, 06:13 PM
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Not all codes are created equal. Direct connect to garbage disposal perfectly legal and allowed on all residential work where I live.
 
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Old 03-16-05, 06:19 PM
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I think they are referencing to plumbing principle #15

Prevent contamination. Proper protection shall be provided to prevent contamination of food, water, sterile goods, and similar materials by backflow of sewage. When necessary, the fixture, device, or appliance shall be connected indirectly with the building drainage system.

I took that verbatim out of my Ky state code book, but like you said, they do not enforce air gap installations in Ohio.

But, in Ohio, you will not find a commercial food establishment without air gaps on their dishtank setup. Just laxed on the residential application.

But in the scope of thinking in regards to whether it is code enforced or not, the application far outweighs the logic of whether or not to use it. It is a protective feature at $2 that can keep human life from being harmed.

Sooner than later, a thread will come through this site this year where a member will disclose backup from the kitchen sink going straight into the dishwasher.

A very common situation when the dishwasher is directly tied into the garbage disposal or tapped tailpiece. This puts the tie-in almost 6 to 13" under the flood level rim of the fixture it serves.


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http://forum.doityourself.com/showthread.php?t=205367
 

Last edited by DUNBAR PLUMBER; 03-16-05 at 09:02 PM.
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Old 03-17-05, 07:07 AM
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SOLUTION: installing an air-gap

Guys,
Thanks for all the tips, here's what I did:

1. I connected the dishwasher's drainage hose to the inlet (small port on the air gap). I used a knife to cut the end of the dishwasher's hose down so that the diameter was appropriate to fit over the small inlet on the air gap.

2. I bought a piece of pre-cut 7/8" drainage tubing and attached that to the air gap's outlet (big port).

3. I removed the top screw on the air gap and placed the air gap under the sink and up through the sink hole that used to be occupied by the sprayer. I tighhtened the screw back on from the top.

4. I connected the other end of the 7/8" drainange hose to the garbage disposal's dishwasher drain port (after previously punching out the hole in this port)

Thank you,

-MC
 
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