Looking for some advice or suggestions. We remodeled our kitchen about 2 ½ years ago, replacing the dishwasher, sink, and disposal. Since then the air gap has been clogged preventing the dishwasher from draining (triggers error message). This has occurred about 5-6 times. The blockage is an accumulation of food debris, which I also find beneath the filter screen over the discharge pump. This debris is considerably larger than could fit thru the screen (which is not loose or damaged). I assume that water and food debris is backing up from the disposal, into and past the air gap, and siphoning into the dishwasher. However, We’ve never had water come out of the air gap, nor have we observed water backing up into the sink, which it would do if there is a drain problem (since the sink drain is below the airgap). One suggestion I’ve received is to remove the air gap and just use a high loop. But I’m concerned this will just allow more debris to siphon back into the dishwasher. Any thought, please?
Dishwasher air gap blockage
- Thread starter tom0527
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The error code on the dishwasher would not be because of an air gap fitting. The hose from the dishwasher comes up to the air gap into midair and then drains down a 7/8" hose from there.
There is no way anything from the kitchen sink or the disposer can get back to the dishwasher.
I would open the dishwasher and remove the screen at the bottom of the unit and check that. Often that is where you will need to clean.
There is no way anything from the kitchen sink or the disposer can get back to the dishwasher.
I would open the dishwasher and remove the screen at the bottom of the unit and check that. Often that is where you will need to clean.
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The error code on the dishwasher would not be because of an air gap fitting. The hose from the dishwasher comes up to the air gap into midair and then drains down a 7/8" hose from there.
There is no way anything from the kitchen sink or the disposer can get back to the dishwasher.
I would open the dishwasher and remove the screen at the bottom of the unit and check that. Often that is where you will need to clean.
Hi Terry,
Thanks for your quick reply. To clarify, the error message states that the dishwasher (Bosch 800 series) will not drain properly. Among the solutions is to clean the filter screen, check the discharge pump area for obstructions, and check the discharge hose for obstructions. If I only clean the filter screen and restart, I get the same error. When I check the air gap, I find debris; after cleaning that and restarting, the cleaning cycle completes with no error. When I remove the screen to clean I invariably find debris too large to get thru the screen, and I've never found the screen to be loose or out of place.
I also can't understand how there could be backflow into the dishwasher, but thats the only explanation I can come up; hence my reason to post this and solicit others advice and comments.
This doesn't happen very frequently - every few months - but its annoying and very perplexing.
Which leg of the air gap do you find the debris in? I suspect the dishwasher side. If so, I think the debris has to be from the dishwasher, not the disposal.
So how does the debris make it through the screen? Maybe it extrudes through screen, and re-forms.
I would be tempted to try a different air gap.
There's a removable cap at the top of the air gap, and the blockage is just below it; I can't tell which leg it may have come from. The debris I find in the sump below the screen is too large & solid -eg, a whole blueberry - to extrude thru the screen. Is there any other way to bypass the screen? I don't see another opening anywhere inside the dishwasher. Also, are there different designs for air gaps? I got this one online because it was cheap and the cover matched the finish on the faucet.
Kreemoweet
In the Trades
So how in the world can debris and water come up into the air gap (and back down into the dishwasher) without also spewing all over the sink/counter? That's the whole point
of an air gap. There can not be any "siphonage" in either direction in a correctly made air gap. Maybe you bought some special Chinese "air gap" where they left out the "gap" part? Lets see a photo of the thing! Running the disposal with the airgap cap off
should show if stuff is being pumped back up the D/W drain, which I do not think is at all normal. Do you have a Chinese garbage disposal also?
of an air gap. There can not be any "siphonage" in either direction in a correctly made air gap. Maybe you bought some special Chinese "air gap" where they left out the "gap" part? Lets see a photo of the thing! Running the disposal with the airgap cap off
should show if stuff is being pumped back up the D/W drain, which I do not think is at all normal. Do you have a Chinese garbage disposal also?
Jeff H Young
In the Trades
putting plates food still on them in dishwasher. Code requires airgap. Your putting the food in the DW
What I think may happen is that when the path clogs, the dishwasher senses that quickly enough to prevent spewing. It then shuts down the DW pump, and indicates an alarm.
Bannerman
Well-Known Member
A partial blockage could exist within the drain line from the DW to the air gap. The line from the DW should be smaller diameter compared to the line flowing to the garbage disposal.
The screen in the dishwasher only prevents larger items from entering the pump and drain line. Small debris and grease from the dishes will continue to be disharged through the DW drain line which is likely what has accumulated in that line.
The screen in the dishwasher only prevents larger items from entering the pump and drain line. Small debris and grease from the dishes will continue to be disharged through the DW drain line which is likely what has accumulated in that line.
Jeff H Young
In the Trades
so removing the blue berry fixed problem ? Do you belive the blueberry plugged it up and caused this problem? maybe a bad sensor? DW pumps at good amount. Could be a bad airgap I doubt it but take a close look see if something looks wrong. could be the dishwasher!
Thanks to all for comments & suggestions. Ran the DW today and watched the airgap with cover removed. There is definitely a gap, and I could see water flowing in and out to drain during discharge cycles; did not see any food debris. The disposal drained quickly with no back up or residual. Put a bunch of food scraps into the disposal and ran it, and didn't see any backup into the air gap. When completed, I checked the filter and sump and didn't find anything significant.
Food debris from the DW does seem like the most likely source. This model has a 3 -stage filter assembly: a "large object trap", a "flat fine filter", and a "micro filter", and there's only one way to put it in, so how stuff gets thru is beyond me. Of course whomever coined the phrase "idiot proof" didn't know me.
Isn't there a tv show "Unsolved Mysteries"? Maybe they'll do an episode on this.
Food debris from the DW does seem like the most likely source. This model has a 3 -stage filter assembly: a "large object trap", a "flat fine filter", and a "micro filter", and there's only one way to put it in, so how stuff gets thru is beyond me. Of course whomever coined the phrase "idiot proof" didn't know me.
Isn't there a tv show "Unsolved Mysteries"? Maybe they'll do an episode on this.
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