Bosch Dishwasher not cleaning properly

[ozzie908]

Similar problem

My Miele dishwasher drains into the waste disposer it does remove grease etc but a bad design in the plumbing under my sink is, there is no way to clean out the pipe that goes to the main drain, We have to remove all the pipes and use a pressure pump to unblock it now the problem I have had is the water pumped from the DW never goes back into it as it has a anti syphon which believe it or not is just a large stainless steel ball sat in a housing that drops when the pump stops thus preventing back flow. A simple but effective device I wish the plumbers and electricians had thought about my sink though as we have a boiling water tap with a trap that allows unused water to drain away if we have a blockage every thing flows out of this little trap and guess what's been fitted directly under it ????? Yes the power points for the DW etc so off goes the power so not only is it wet its now dark.... All good fun lol

 

[combo52]

Built-In DW Air-Gaps and other Anti-Siphon Devices

Most built-in DWs in the US originally required a drain air gap , a drain AG is the ONLY way to completely insure that dirty can-not possibility back up into your DW that is always installed lower than the sink and sinks drain line.

 

Many parts of the US did not require AGs so DW manufactures started building various types of built-in check valves into the DWs plumbing, these helped a lot, but if a tiny bit of glass or other object gets in the CV it will not function.

 

Having a high loop also helps a lot but of course dirty water can still siphon back through a HL.

 

Because of these improvements in DW design most places in the US have stopped requiring sink mounted AGs, here in the Washington area we no longer have to install them. We just loop the drain line as high as possible under the sink and secure it to the under side of the countertop and hope for the best. This type of installation would not pass muster in commercial installations etc however.

 

Hi Rich, in your case you can probably just get rid of the air gap or replace your AG, an AG should almost never clog so there is truly something wrong with your current AG if you are having to clean it on a regular basis, we still have thousand of customers with AGs and they generally do not even know they have one let alone know how to clean it.

 

John L.

 

[foraloysius]

No air gap here either, never seen one in the NL. My dishwasher is connected to the sink drain.

 

[foraloysius]

I found an installation instruction for my dishwasher online. No air gap required.

 

[Marky_Mark]

My dishwasher in Spain is connected directly to the Insinkerator disposal -- all that hot water and detergent running through it keeps my disposer and drains as clean as a whistle.  No air gap, but it does have a check valve of course, which functions as Ozzie describes in his post above.  I have never seen dishwasher air gaps outside of the US.  

 

The most useful thing about having a sink with an air gap is that you have the option (local code permitting

) of removing it and using the hole for something else such as a soap dispenser, air switch, sprayer, reverse osmosis, boiling water unit etc.

 

I can't offer any advice to the OP that hasn't already been mentioned.  I hope you get the problem resolved!

 

[sudsmaster]

Thanks for all the responses. This DW is a Bosch SHU43-C/U. I'm not sure if it has a check valve, but I suspect it does.

 

The air gap is very old - made of copper mostly. The problem is that relatively small pieces of food, maybe 1/2" long and 1/4" wide at most, get caught at the top of the air gap before the path goes 180 degrees down again. There simply is not enough clearance between the copper feed pipe into the air gap and the plastic cap that covers it - too tightly it would seem. I have tried cutting away part of the air gap to make more clearance, but this doesn't eliminate the problem.

 

I will probably try by-passing the air gap  and monitor the DW sump to make sure it doesn't flood from the sink. I doubt it will. I figure the SHU series is new enough that it has built-in anti-drainback features as mentioned.

 

I will however keep the current airgap in place, but not connected to anything, since I have a few vintage American style DW's in storage, one of which might wind up in place of the Bosch should it ever finally die for good.

 

 

[gelaundry4ever]

finish ultimate

Try Finish Ultimate. I'd also set the rinse aid aid setting back to default or the max setting.

 

[DADoES]

 
Jerome, perhaps you don't realize this thread is 4 years old.  The post previous to yours is dated 11/27/2019.  Everyone involved has probably solved their problem and/or moved on.

 

[daveamkrayoguy]

A Bosch-apocalypse?—this great brand now jumping the shark?

Well it’s on that note I’d like to believe that a dishwasher that’s a brand like Bosch even that old or older with proper care will still clean that good today!

— Dave