# What is next to my faucet?



## msgbg (Jul 29, 2009)

I just bought a 1995 Peach double wide and there is this thing next to my kitchen faucet.  It is plastic and has a chrome cap on it,  but there is a hose running to it from the plumbing underneath.  Can someone tell me what it is?


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## travelover (Jul 29, 2009)

It is probably a dishwasher drain vacuum breaker.


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## Nestor_Kelebay (Jul 29, 2009)

Msgbg:

If the hose running to that thingie is connected to the drain pipe under the kitchen sink downstream of the sink's P-trap, then I'd agree with Travelover that it's a spring loaded air vent.

You see, when water drains down a plumbing pipe, it can create a partial vaccuum behind it just like the way a subway leaving the station can create a partial vaccuum (and hence the wind you feel) behing it.

The concern is that if this partial vaccuum is strong enough, it can suck the water out of he p-trap under the sink.  If that happens, then the stench in the city sewers that your main drain line connects to can come wafting up your house's drain piping and stink up your house sumthin awful.

There's probably a weak spring in that thingie that keeps it closed most of the time.  But, when there's a strong enough partial vaccuum formed behind draining water in your drain piping, that thingie opens to allow air to rush in behind the draining water.

That way, the partial vaccuum behind the draining water will never be strong enough to suck the water out of your kitchen sink's p-trap.'

And, as long as there's water in that p-trap, the stench inside the sewers can't get into your house through your house's drain piping.


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## Redwood (Jul 30, 2009)

It is an air-gap for the dishwasher drain.







Required by UPC Code to prevent water from a clogged kitchen sink line fron draining back into the dishwasher.


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## inspectorD (Jul 30, 2009)

I like when they used to be installed on the top of the kitchen sink. If there was a clog...you should see the results of the "hose in the house" syndrome.
I have been sprayed more than once with an air gap device...the realtors don't know what happened, just that they are all wet.


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## majakdragon (Jul 30, 2009)

Air Gap devices used to be required in many areas. After a few years, and many problems, most areas took the requirement out of their codes.


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## Nestor_Kelebay (Jul 30, 2009)

Redwood said:


> It is an air-gap for the dishwasher drain.
> Required by UPC Code to prevent water from a clogged kitchen sink line fron draining back into the dishwasher.



Oh, I see.

Since the dish washer pumps the water out, it could fill up the drain pipe from the kitchen sink (if that pipe is partially clogged).  Positive pressure on the doo-hickie closes it so that the water is pumped into the drain pipe, not all over the counter top.  And with the drain pipe full of water, that water could drain back into the dish washer when it's pump stops and perhaps create an unhealty situation with bacteria in the drain pipe flowing back into the dishwasher.  But, with that doo-hickie, negative pressure opens it, so ONLY the water between the dish washer pump and the doo-hickie drains back into the dish washer.  And, since the doo-hickie opens on a negative pressure, it allows air into the drain pipe as it drains.

Is that about right?


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## MACPLUMB (Jul 31, 2009)

Redwood said:


> It is an air-gap for the dishwasher drain.
> 
> 
> 
> ...


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## MACPLUMB (Jul 31, 2009)

Part 2 
you have air gaps all around plumbing such as the break between 
your sink and the faucets in your house !
Everything possible is done in plumbing to "prevent" cross contamination of your sewer and your drinking water  also knone
as potable water supply

that is why plumbers protect the health of the nation !

And also why there is a lot more to plumbing then being able to put
two pieces of pipe together


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