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I installed a dishwasher in an old house that had no room under the kitchen sink for a tailpiece with a dishwasher drain hose burr. So I added a 1.5-in. PVC drain line (with trap) in the basement and routed the dishwasher drain hose to the new line. Between the dishwasher and the new PVC, I installed an air gap at kitchen counter top height. All seemed perfect until the dishwasher flushed. When it flushed, waste water came flying out of the air gap and onto the counter top.
Are air gaps just a way of asking for trouble?
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Yes, but vent stacks are nice.
b Been there, done that, can't remember
*Dale,Here in my county air gaps are not required and I did not install one in my new house. I followed the directions of making sure the discharge hose rose to at least 20" off the floor and connect to the drain pipe also at least 20" off the floor. I strapped it to the cabinet behind the sink. To quote Kennmore manual:You must:1. have a high drain loop 20" above the subfloor or floor.2. connect drain hose to waste tee or disposer inlet above drain trap in house plumbing and 20" minimum above the floor.3. use an air gap if the drain hose is connected to house plumbing lower than 20" above subfloor or floor.Is the new line and trap you installed vented properly? Check a plumbing book like Peter Hemp's book by Taunton for trap and vent specifications.Frank
*There are some airgaps that, due to their internal configuration, are more prone to discharge than others. I had this problem not too long ago and simply changed the air gap. Take the cover off and if it looks like the the flow through it is restricted, look for another one.
*I don't have one on mine and never had a problem. I have a nipple with a tee in the drain line from the sink. Connected the hose right to it. Didn't pat a whole lot of attention to height, but it had to go up and over then down to connetc, so I guess I made the loop. No chance of every getting waste back into the domestic water supply here, just a chance of backing up into the washer and onto the floor - not much worse thsan a toilet clog.-Rob
*I've been skipping the air gaps and making the highest loop possible under the counter, as recommended, works great. Was told that modern dishwashers are better protected against siphoange. Air gaps do malfunction -- any chance you hooked yours up backwards? sorry if that's an insulting question... :)One problem: is your trap legal -- distance below the fixture? The risk is that the trap seal will be blown out. Make sure your vent takeoff level with the trap, so air can flow while water runs out. Is there a garbage disposer -- these have D/W waste inlets.
*Turn the slot in the decorative cover so it points at the sink, assuming code requires you to have one. Or, if not follow the other suggestions and get rid of the thing.
*Uh, Dale, what exactly did youi dooin your dishwasher before you flushed it?
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I wasn't going to announce this, but you know how dishwashers have that "flush" function? I was curious. I was curious to see how it would work -- in the same way that every kid is curious about whether the toilet will flush a drinking cup.
*just install a garbage disposal and bag the air thing, they are a pain in the ..... follow the mfgr. instructions about drain loop and put a soap or hot water disp. in the hole you have in the sink where the air gap is now. lol. jay//
*I don't think the problem is with the air gap per se. I think the drain is clogged, and the discharge is backing out of the air gap. From the sounds of things your trap is low enough. This sounds like a similar occurance to when a dishwasher is plumbed to a garbage disposal, and the air gap overflows when the disposal has not been cleared.By the way, I never use air gaps either, but I am sure the problem is downstream of the airgap.
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I installed a dishwasher in an old house that had no room under the kitchen sink for a tailpiece with a dishwasher drain hose burr. So I added a 1.5-in. PVC drain line (with trap) in the basement and routed the dishwasher drain hose to the new line. Between the dishwasher and the new PVC, I installed an air gap at kitchen counter top height. All seemed perfect until the dishwasher flushed. When it flushed, waste water came flying out of the air gap and onto the counter top.
Are air gaps just a way of asking for trouble?
No one posted about this so I thought I'd bring it up.
One thing the air gap (or high loop in the drain line) is good for is to stop backwash from the drain entering the dishwasher and contaminating it. Most city codes require an air gap.