Dishwasher air gap issue
barkinmarm
5 years ago
The problem I've been having with my dishwasher air gap is fairly minor but a little bit annoying. During a cycle about 1/4 cup or so of water escapes the air gap and pools onto the sink edge. I've done some analysis and here is where I'm at:
- air gap screw cap is snug so the discharge should be moving into the drain pathway
- air gap body and drain hose to are clean, no kinks
- drains to sink (not disposer). properly angled "t-pipe" in place, above trap. trap is clean and free
- discharge hose from dw is clean, clear and not kinked
The only thing I can guess is it might be the discharge hose itself. The original installer did not reduce the length at all and left all the slack sitting at the back of the cabinet. I know that in some states where code does not require an air gap the discharge hose should have a loop anchored as high in the cabinet as possible. I've now created a loop to see if it makes a difference. It may be a bit hard to see all of it from the photo but it loops up from the cabinet hole (back of photo), down to cabinet bottom, and back up to the air gap. My concern is whether doing it this way is a big "no-no". Any thoughts or advice?
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Comments (16)
weedmeister
5 years agoRelated Discussions
dishwasher install with drain below floor - no air gap?
Comments (7)Yes, frodo here above, and live_wire_oak in the other thread (linked to above) got it right. -- 99.9% right. I'll add a bit of context, based on my knowledge of DWV plumbing. I am happy to share and to read feedback, and I don't mind plumbers telling me more.. An indirect connection (before _Any_ P trap, not just the sink's P trap) lets air in or out, preventing the draining water from sucking open either the P trap or the DW's base (its "sump") which is supposed to have some standing water left in it. ((Note that doing the opposite would have the same effect as two P traps in series which is disallowed)). An indirect connection is a set up that lets the drain gurgle: it mixes with room air. It can look like a standpipe (that looks like your clothes washing machine's standpipe) or it can look like some other set up that looks_different but does the_same thing. This is why your DW makes gurgling noises in the kitchen drain pipe when it drains: it is pumping water into the drain prior to the P trap, so you hear it. It is not allowed to connect the DW drain to your plumbing behind a P trap, it must be in front of a P trap. You Are allowed to send the DW drain hose from an Air Gap directly to the kitchen drain without going through the garbage disposal first. The option to route through a disposer is one optional route. It is one option out of a very limited number of options. A "High Loop" brings the DW drain hose to the house plumbing before the sink P trap also, and in the sink drain is where the gurgling / air-mixing takes place, and that is where you will hear it. A dishwasher _Wye or _Tee is the connection part usually used but any Wye will do. A third option is if you install a separate stand pipe like a laundry standpipe: then that means a separate P trap which then presents other (minor) challenges, since it has to be connected with the right venting behind the P trap; this is venting for sewer gases (not room air venting) which is the usual meaning of venting when plumbers talk to plumbers. When a P trap is under the floor, the drop may be too far and the P trap may self-siphon because the fast moving (falling) water will all slide out. That is inertia because of the fall. However, it is not disallowed, it just calls for a professional plumber or a highly knowledgeable homeowner. (So yes, sometimes a P trap in a basement for a fixture on the first floor can be good; e.g. if it is right under the floor, up against the basement ceiling, and with the right venting too!) As live_wire_oak said in the other thread, this is all part of the plumbing code for health and safety reasons. Sewer gases cannot be allowed to enter a house, so P traps which could siphon themselves out are disallowed, and this is all an exercise in 3-D geometry including the drain diameter. Plumbers spend Years learning this and writing exams, so don't let a plumbing apprentice design your DWV plumbing, and double-check everything even if you think your plumber has all the answers, as they do make mistakes too. I have seen this more than once. The 3D thinking involved is complex, even for a new building where everything is built as a system all at once, but even more-so for a reno or remodel where the "system" is not all visible and sometimes not even fully understood. Above I mentioned that you would hear the DW drain gurgling. If one built a standpipe that got its air from up high in the dropped ceiling, the gurgling noise would be minimized. It would be a tall pipe with a Wye in it to receive the DW hose. HTH -david...See MoreAir gap gurgles like crazy when dishwasher runs - should it?
Comments (17)zl700l, I don't believe there would be anything in a dishwasher that would be sufficient to act as an effective p-trap and I do believe you are basically bathing the dishes in your dishwasher in sewer gas, not to mention airbourne bacteria. The explosion risk of the methane entering the dishwasher is not to be ignored either, I am sure there is plenty of potential ignition sources in there to be of concern, moreover, people die in homes infiltrated by sewer gas. The risk is not to be scoffed at. Moreover, it's just common sense- the practice is dangerous and illegal, makes your house unmarketable and subject to being condemned or remediation orders, and just a bad idea. We're talking about a little gurgling water, not freeway noises. I like hearing the dishwasher when it drains because a) I know it's working and how far along it is, and b) having it drain into the p-trap means that it's charging it (keeping it full, avoiding gas infiltrations) and the dishwasher detergent going through the trap keeps it clean and smelling decent. As the the 'banjo' vs 'my house is bigger than yours' contest, I don't believe in being rude as it were but I believe it's not a question of how much money someone has, but how much common sense /stubbornness they have....See MoreBosch Dishwashers don't need air gaps?
Comments (13)I installed an air gap for my dishwasher because it made sense to have it for sanitation safety purposes. If your Bosch dishwasher has a backflow preventer then you're that much safer, but why not have both in case the backflow preventer on your dishwasher fails. However, if you want to check the code then you could call the San Francisco Office of Building Inspection and ask them. I also did a quick online search and this is what I found. From the 2013 California Plumbing Codes (Scroll down to page 56): "414.3 Drainage Connection. Domestic dishwashing machines shall discharge indirectly through an air gap fitting in accordance with Section 807.4 into a waste receptor, a wye branch fitting on the tailpiece of a kitchen sink, or dishwasher connection of a food waste grinder. Commercial dishwash- ing machines shall discharge indirectly through an air gap or direct connection in accordance with Section 704.3 with floor drain protection." http://www.iapmo.org/2013%20california%20plumbing%20code/chapter%2004.pdf From the City of Palo Alto, Building Division, Final Inspection Form (scroll down to the top of page 16): "Airgaps required - No domestic dishwashing machine shall be directly connected to a drainage system of food waste disposer without the use of an approved dishwasher airgap fitting on the discharge side of the dishwashing machine. 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.(2010 CPC section 807.4)" https://www.cityofpaloalto.org/civicax/filebank/documents/17668 Palo Alto is close to San Francisco so I imagine they would follow similar plumbing codes....See MoreThose with Fisher Paykel Dishwasher Drawers... Did you use...(air gap)
Comments (21)There's no need for *any* air gap if such is not required by code. If it is required or one wants to install an air gap regardless, then the dual-type is a better choice for DishDrawers than a non-dual ... which is not to say that a standard air gap can't work. A Y-adapter is included with double-drawer units to attach the two drain hoses to a single plumbing connection, so it can be used to attach them to the standard air gap ... but the standard type may in some cases allow backflow from one drain hose to the other, although a proper high-loop should avoid the backflow actually getting into the drawers. It all just depends on the particulars of the individual installation/arrangement....See Morecat_ky
5 years agolast modified: 5 years ago
Fori
5 years agooneandonlybobjones
5 years agolast modified: 5 years ago
PROJoseph Corlett, LLC
5 years agooneandonlybobjones
5 years agolast modified: 5 years ago- PRO
Joseph Corlett, LLC
5 years agolast modified: 5 years ago barkinmarm
5 years agoweedmeister
5 years agobarkinmarm
5 years agoHaving run a cycle the problem remains. I had hoped that having the high loop might have a small impact on the discharge pressure at the end of the hose and into the air gap. Yes, to all the engineers out there, that was probably wishful thinking. During the dw cycle I watched the gap at the stages of draining. Water would flow up against the cap and back down as expected. Water never worked its way higher than the slots (see red arrow) and out over the top of the cap which is what I thought was happening. Yet water worked its way out of the cap threads and down the side onto the sink. So I think cheap plastic and crappy engineering are the culprits here. I am going to wrap the threads with some thread tape and see if that reestablishes the seal. Meanwhile, I'll be looking for an air gap with a better design and build. In a couple of years when I put in new countertops and a sink I'll be going with the under counter gap only.
- PRO
Joseph Corlett, LLC
5 years ago deananywhere mn
3 years agobarkinmarm
3 years ago
richard thomas
2 years ago
blazeaglory
last yearlast modified: last year
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