air gap in newer dishwashers

[daniel nantell]

Did they start building the air gap in the dishwasher themselves , dont see many air gaps on top of counter. ????????????

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[Rick Hurst]

They may have a "high loop" in the drain hose instead. This could explain why your not seeing them.

rick

[Scott Patterson]

Did they start building the air gap in the dishwasher themselves , dont see many air gaps on top of counter. ????????????

In my twelve years of inspecting homes in the South I have never seen an air gap device installed on top of a sink. I know what they look like, but I just have never seen one. I really think that this is more of a regional or local item.

As for them being built into the dishwashers, I would have to say that just about all dishwashers have some type of check valve or a high loop installed on them. The problem is that we can not see it!

I watched a cheap GE dishwasher being installed the other day in a new home. The drain line was looped up and over the top of the unit so when it was placed under the counter it was higher than the drain on the sink. This is a high loop device, you just can't see it after the unit is in place.

[Richard Rushing]

Dan,

They can have either a high-drain loop OR an air-gap. Not required to have both-- just required to have one or the other.


Rich

[Nolan Kienitz]

Dan,

And then there are those 'spensive foreign D/W's that have a checkvalve built into the drain mechanism on the unit.

I've run into a few of those units when I was doing some extremely 'high-end' new home finals while I was inspecting in the Houston market.

Many of these D/W's started at about $3K to $4K and on up from there.

[daniel nantell]

what the best to write up, air gap not visible????????????????????f

[Rick Hurst]

The air gap device was not visible.

Air gap device was not visible.

Inspector could not determine if a air gap device was present.

Seriously, just write up things as you see them. Don't feel like you have to be wordy. Simple and to the point.

rick

[Jim Luttrall]

Good diagrams Richard, where did you get those?

[Jerry Peck]

Before jumping on the "air gap" bandwagon and start writing them up, and to say yourself from looking foolish ...

First check to see if the dishwasher drain hose is installed with a high loop (high point of the drain line up near the underside of the countertop) - if that is there, that is *most likely* all that is required. If that is not there, then there still may be a high loop built into the drain line where it exits the dishwasher and is attached to the side of the dishwasher - many dishwashers today only require the top of the high loop to be 21" (and some are even less than that) above the floor), meaning that just because you do not see a high loop on a newer dishwasher does not mean it is incorrect.

In over 16 years of inspections before I retired from home inspections, I have *NEVER* seen an air gap installed - just high loops.

Even if your code *requires* an air gap device, your code also likely says that all appliances must be installed according to the manufacturer's installation instructions, and if those specify a 'high loop', or, an 'air gap *or* a high loop', then no air gap is needed.

Thus, "air gaps" dropped almost completely off my list - it was replaced with "high loops".

[Richard Moore]

"Even if your code *requires* an air gap device, your code also likely says that all appliances must be installed according to the manufacturer's installation instructions, and if those specify a 'high loop', or, an 'air gap *or* a high loop', then no air gap is needed."

Trouble is that most manufacturer's instructions also have CYA wording like in the Bosch diagram below. Air-gaps are by far the norm around here. In fact, I can't remember the last newish home without one. But...as I very much doubt the laws of physics are any different here than other parts of the country, I'm quite comfortable with a high-loop instead on older homes or remodels.

Miele is the only brand I've found so far that actually documents a check valve and doesn't require either but I'm aware that some other newer models can have the high loop attached to the back of the unit. Wouldn't it would be nice for us 'spectors if they would stick a little diagram or label on the front somewhere?

[Nolan Kienitz]

... and then there is the TX TREC SOP:

(a) Dishwasher. The inspector shall:

(4) report as in need of repair deficiencies in the
discharge hose or piping or the lack of back flow

prevention;


It lists 8 items to cover ... I only picked up the one relating to this thread.

[Jerry Peck]

... and then there is the TX TREC SOP:

(a) Dishwasher. The inspector shall:

(4) report as in need of repair deficiencies in the
discharge hose or piping or the lack of back flow

prevention;

Define "backflow prevention".

'Air gap'?

'High loop'?

'Check valve'?

If it does not define "backflow prevention" as one of those three, then anything which the HI considers to be helping restrict backflow could meet that, and, if it does define backflow prevention as just one of those and gives no alternative(s) - then a recognized alternative would need to be written up as a deficiency in need of repair ... and how stupid would that make the HI look?

HI: 'Dishwasher does not have an air gap - install an air gap.'

Plumber: 'Does not require an air gap, it has a high loop, which the manufacturer allows as does the code.'

HI: 'Dishwasher does not have an air gap - I am required to report that by TREC as a deficiency requiring repair.'

Plumber: 'Man, you guys sure have stupid laws, making you write something up for repair which meets code and manufacturer's installation instructions and does not need to be repaired.'

HI: 'I know, but I am still required to do so. Dishwasher does not have an air gap and needs to have an air gap installed.'

I feel for you guys.

[neal lewis]

Nolan, I thought I've seen almost every type of DW out there.

What type STARTS at $3-4,000?

[Richard Rushing]

Define "backflow prevention".

'Air gap'?

'High loop'?

'Check valve'?

If it does not define "backflow prevention" as one of those three, then anything which the HI considers to be helping restrict backflow could meet that, and, if it does define backflow prevention as just one of those and gives no alternative(s) - then a recognized alternative would need to be written up as a deficiency in need of repair ... and how stupid would that make the HI look?

HI: 'Dishwasher does not have an air gap - install an air gap.'

Plumber: 'Does not require an air gap, it has a high loop, which the manufacturer allows as does the code.'

HI: 'Dishwasher does not have an air gap - I am required to report that by TREC as a deficiency requiring repair.'

Plumber: 'Man, you guys sure have stupid laws, making you write something up for repair which meets code and manufacturer's installation instructions and does not need to be repaired.'

HI: 'I know, but I am still required to do so. Dishwasher does not have an air gap and needs to have an air gap installed.'

I feel for you guys.

I don't know why you would state such... our SOP does not state that we have to be an arse about it. It states that we just have to report the lack of back-flow prevention-- it does not state which one must be present, just that it must be report if it is not. That's not difficult or confusing at all.

Anyone who would get into a pizzing contest with a plumber like the above, would deserve to be beat with the high drain loop hose.

Rich

[Jerry Peck]

It states that we just have to report the lack of back-flow prevention-- it does not state which one must be present, just that it must be report if it is not. That's not difficult or confusing at all.

Rich,

That's why I said: "Define "backflow prevention". "

If there is not a definition of "backflow prevention" then the only real definition is that used in the codes (for the plumber to use) and a "high loop" is not going to be classified as "backflow prevention" in any code I am aware of.

Of the three listed, only an air gap is. Even a single check valve is not considered backflow prevention (at least I don't think it is).

Which lead to my little game of the HI writing it up and the plumbing saying a high loop is okay, with the HI saying ...

*IS* "backflow prevention" defined in the TREC standards? If not, let the games begin.

[Rick Hurst]

This is my experience with DW's and air gaps.

I've removed many DW's and installed some over the years. (remodels)

If the dishwasher drain hose is running upwards and over the top of the kitchen cabinet directly below the counter top, then the hose is connected to the disposer. I would consider that as acceptable.

If the drain hose is passing through the cabinet at the lower section of the cabinet and connected directly to the disposer, it probably does not have a high loop or an air gap as recommended.

And if they do actually have the air gap device on top of the sink, it is always turned backwards cause the wife doesn't want to look at that dumb opening on the front of it anyway. Am i wrong? How many of you hear that?

rick

[Carol Perkins]

Those inspectors who are working in areas where the Uniform Plumbing Code is inforced should be seeing air gaps above the sink. While home inspectors are not code enforcers they should be aware of the requirements. In the 2000 UPC 807.4 requires an 'air gap' with the flood level markings at or above the floor level of the sink or drain board. That would preclude the use of a high loop.

My experience has been a high loop can allow a stopped up drain to back up into the dishwasher. I use to recommend installing an airgap or high loop but now I require an air gap as a health item.

[John Goad]

I see air gaps all the time in ky, & very rarely even see a high loop in tn.

[Rick Hurst]

If persons didn't think their dishwasher was a disposer also we probably wouldn't even need a air gap or a high loop.

As my mom used to say in her great Texan vocabulary, "Wrench (rinse) off those dishes before loading them in that thar dishwasher."

rick

[Nolan Kienitz]

Nolan, I thought I've seen almost every type of DW out there. What type STARTS at $3-4,000?

Neal,

I can't recall the names off the top of my head, but there were a few of them from Europe & Scandanavia.

Quite nice units ... I guess if $$ are not a problem.

Even the contractors I was working with were a bit in awe of some of the appliances that were being put in a few of the properties.

[Nolan Kienitz]

... *IS* "backflow prevention" defined in the TREC standards? If not, let the games begin.

Jerry,

That would be expecting far too much of the TREC SOP to expand to that amount of detail.

Yes, sometimes the back/forth can be fun down here when it comes to such.

[Kevin Luce]

http://products.geappliances.com/Pro...temid=31-30566

Read page 3

http://www.vikingrange.com/MEDIA_Cus...039_f20244.pdf

Page 7

[Kevin Luce]

I don't know if I would use that picture with it showing 20 inches close to the counter.

[Richard Moore]

I don't know if I would use that picture with it showing 20 inches close to the counter.

I have to agree...sort of. I actually grabbed that photo just 2 days ago, direct from the online install manual specfic to the Bosch model installed in the home I was inspecting. Old home with new granite counters and no air-gap or high loop. No hole to easily install an air-gap and I had discussed the high-loop option with the client on-site.

I also thought the 20" thing was a little weird. German midget kitchens? I included the diagram but this is the actual language from the report.

Repair: The dishwasher drain line has been plumbed incorrectly. There is neither the required air-gap nor the less desirable “high-loop” in this line before it attaches to the disposal. This can lead to a cross connection where dirty water can back-feed into the dishwasher. Recommend installation of an appropriate air-gap or a high-loop. (Note: the diagram below is from the Bosch installation manual for this dishwasher. I recommend you ignore the 20” minimum and make the loop as high as possible.)

[Andrew Buckwell]

The issue as I see it is that the dishwasher cannot drain if the garbage disposal dishwasher intake pipe becomes blocked without an air gap device. This is from Mike Casey:

"All dishwashers built during approximately the last 20 years have a built-in water supply air gap to prevent cross-connection and possible backflow to the water supply. If you look at a dishwasher out of the box prior to installation, it is the hose looped above and into a funnel-like device on the side of the dishwasher. This is the built-in supply air gap.

Most dishwashers do not have built-in backflow prevention from the drain hose side. This is where the drain air gap device functions; to prevent contamination of the inside of the dishwasher, not the water supply. This usually would occur if there was a kitchen sink drain backup. The UPC (western code) requires that an air gap device be installed to prevent backflow into the dishwasher (see illustration). This device prevents backflow by keeping the connection above the fixture flood level rim and having an opening to atmosphere (prevents a siphon). Most IRC and other codes allow the high loop method (fasten drain hose high at underside of countertop). This installation will work in most cases unless a siphon occurs.

(see previous picture of air gap device)

As you can see, the countertop air gap device for the drain prevents only contamination of the dishwasher, a disgusting event, rather than contamination of water supply, a potentially hazardous event".

Mike Casey
Kaplan Professional Schools

Additional information is available at ITA Home Inspection Training Schools - Become a Home Inspector

[Thomas Simstad]

Hi Guys,

The way I read 807.4 of the UPC, it specifically states the words:

"....Listed airgaps shall be installed with the flood-level (FL) marking at or above the flood level of the sink or drainboard, whichever is higher."

To me, the language is quite clear, the airgap must be a LISTED device (as defined in the UPC - in the US of A, the UL label common), and it must have a flood-level marking.

Just say no to loops and look for a Listed airgap with a flood level making that is properly installed.

Thanks, Tom

[tom harding jr]

Hello
Check your local plumbing codes some areas dont require the use of air gaps some states are just ok with a loope in the dishwasher drain line.
A air gap is to prevent the dirty drain water from going back into the dishwasher.(proventing cross connections)
Tom

[Jerry Peck]

Hi Guys,

The way I read 807.4 of the UPC, it specifically states the words:

"....Listed airgaps shall be installed with the flood-level (FL) marking at or above the flood level of the sink or drainboard, whichever is higher."

To me, the language is quite clear, the airgap must be a LISTED device (as defined in the UPC - in the US of A, the UL label common), and it must have a flood-level marking.

Just say no to loops and look for a Listed airgap with a flood level making that is properly installed.

Thanks, Tom

Before you start writing that up and creating a whole bunch of trouble for yourself ... first check to see if the UPC is even the adopted code in your area - most likely ... it is not ... in which case the high loops are the APPROVED answer.

Also remember that the codes will require the appliance to be installed as listed and labeled, i.e., in accordance with their installation instructions, and if those installation instructions specify the high loop ... you could be voiding the listing by installing the air gap if the air gap is not a choice in the installation instructions.

The code is, many times, a double edge sword and cuts both ways.

[Ted Menelly]

Thread started 11/29/2007 almost exactly 4 years ago