Thread Number: 78061  /  Tag: Modern Dishwashers
I beat the Bosch!
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Post# 1020711   1/10/2019 at 02:13 by SudsMaster (East of SF, West of Eden, California)        

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Bosch dishwasher, that is.


Problem: it's been slow draining for some years now. In the past year I started having to run a cancel/drain cycle at the beginning and end of cycles. I cleaned the filter and impeller housing, but still slow draining. It got so bad I had to run two or more cancel drains. Finally I pulled the damn thing out of the counter this evening. Not an easy task, since the previous home owner put in a raised floor (particle board, natch, under sheet vinyl) that means the dishwasher is a very tight fit vertically, Anyway finally got it out.

Inspected the drain hose, no kinks. Some slight kinking of the supply hose, but no biggie. Finally found a youtube video and it mentioned pulling the rubber check valve under the impeller housing. Aha!. The valve is soft black rubber that had deteriorated to the point where it fell apart when I tried to remove it. Took me a lot of teasing tweezing and needle nose pliering in order to get it out. Ran the washer again w/o the check valve: drains like a champ!

Put in an order online for a replacement valve ($5 plus shipping). Tomorrow I'll check with a local appliance parts distributor to see if they have one in stock, as well.

Right now the Bosch is sitting in the middle of the kitchen until tomorrow after work when I work up enough energy to shoehorn it back under the counter.

Oh, I forgot to mention. The darn thing would slowly fill up with water after a cycle was completed and the drain manually activated. Not a lot, but enough to indicate that the check valve was, by that time, toast. Yes, there's a functional air gap on the sink that the DW was attached to, so it probably wasn't siphoning from the disposer.

I was actually contemplating running to Costco and picking up a new stainless Whirlpool DW... also I have a couple of vintage KA DW's in the carport that probably would work great, as well. I'm just used to the Bosch by now and it does a good job outside of the drain issue. We'll see!

(I also have a couple of vintage KA stand alone DW's ... but this kitchen isn't set up for them... yet...

Post# 1020741 , Reply# 1   1/10/2019 at 16:12 by Lorainfurniture (Cleveland )        
Order an inlet valve

If it was slowly filling up with dirty water, likely from the drain. If the water is clean, you have a leaking inlet valve which is a very common failure on those dws. Its one of the very few Bosch parts I keep in the service van.

Post# 1020787 , Reply# 2   1/11/2019 at 01:54 by SudsMaster (East of SF, West of Eden, California)        

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I was figuring the check valve was slowly allowing drain water in the hose to enter the sump. Of course it's possible the inlet valve is hinky, too.

Currently waiting for the replacement backflow preventer to arrive. Probably within a week. Nobody local seems to have them. The replacement in the illustrations seems to be silicone rubber, which should last a lot longer than the black rubber original.

Once the backflow preventer is replaced, I'll see if the sump continues to fill on its own, which would indicate an inlet valve problem.

Post# 1020923 , Reply# 3   1/12/2019 at 11:43 by SudsMaster (East of SF, West of Eden, California)        

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Thanks, Eugene, for bringing the inlet valve issue to my attention. It appears that both the check valve and the inlet valve have failed.

I was able to observe the sump slowly filling up after a full drain, even with the DW sitting outside the countertop but still hooked up. So I'm getting a new inlet valve for this sucker. It's available locally. More than twice the price than online, but the advantage of getting it today is that I can install in in the dishwasher today, put the thing back under the counter, hook it all up, and then install the check valve when it arrives later next week. The check valve can be installed without pulling the dishwasher out of position.

Meanwhile I'm gonna be looking at a modern replacement for the thing going forward. The LG's look good... internal water heaters... and if this repair doesn't work I could always install one of the vintage units I have standing by.

Meanwhile the dishes are piling up. LOL.

Post# 1021026 , Reply# 4   1/13/2019 at 13:49 by SudsMaster (East of SF, West of Eden, California)        

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Update: While the washer was out of its cubby, I pulled the water inlet valve and took it apart. The filter screen was nearly fully clogged with rust from the old steel pipe that runs to the kitchen. I pulled the screen cleaned it thoroughly. Then I went to the local parts distributor and picked up a new valve for $50 just in case. I made sure I could return the $50 inlet valve if cleaning out the old one worked. I had also ordered one on-line for all of $14 free shipping.

Back home, I put the DW back together and in its cubby. Ran a test wash with a full load... Came through it well, albeit with some residual water in the sump due to the backflow preventer/check valve being missing. But the water looked clear. The dishes came out clean although with residual spotting, Probably in part due to the Costco gel pods I've been using. I have a nearly full bucket of Finish which I'll try next. Earlier I had noticed that when I removed the racks and wash arms, the water being expelled by the wash pump was cloudy. Probably that white residue previously noted as characteristic of the Costco gel packs.

One thing I noticed is that the detergent dispenser was full of water mid-way through the cycle before the detergent door opened. Since there are openings in the upper side of the dispenser door, I'm guessing this may be on purpose to help dissolve the detergent quicker. But I never noticed this before... Another Bosch mystery.

The next morning the residual water level in the sump hadn't changed, so I conclude that cleaning the rust out of the inlet valve succeeded in getting it to work properly again. I think I can continue to use the DW w/o the back flow preventer for a week or so, and will install the new check valve as soon as it arrives. This can be done with the DW installed, no problem. Just a little awkward.

It's nice to have the DW working again, even if it's slightly impaired. And I'll be returning the $50 inlet valve for a refund (packaging unopened).

Post# 1021224 , Reply# 5   1/14/2019 at 23:53 by SudsMaster (East of SF, West of Eden, California)        

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Woo woo!

The $14 inlet water valve arrived unexpectedly early today, in Amazon Prime packaging. Which is a bit strange, since I never signed up for Prime. But what the heck. It doesn't look like Amazon charged anything extra.

Still waiting for the check valve, which might be here on Friday.

I am noticing slightly higher water level in the sump, starting to overcome the large fine filter, so I think the inlet valve will have to be replaced anyway.

Post# 1021368 , Reply# 6   1/16/2019 at 10:19 by combo52 (Beltsville,Md)        
Seeping Inlet Valve

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Hi Rich, yes cleaning the inlet screen of an inlet valve will never solve water seeping through it.

Its always fun to take thing apart and try solving problems, but I mention this for the next guy that has the same problem.

In 45 years of fixing DWs I don't think I have ever seen an inlet valve clogged badly enough to affect performance of the DW. On a hot water line most heavy particles settle to the bottom of the WH, and a DW uses far less hot water than showers, kitchen sinks etc so if a DW valve is clogged the rest of the hot water system probably has lots of other clogging long before the DW has any performance issues.

John L.

Post# 1021386 , Reply# 7   1/16/2019 at 13:02 by DADoES (TX,U.S. of A.)        

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Clogged dishwasher inlet valve ... has happened twice at one of RJ's rental properties to the point that the fill level is impaired (I disassembled & cleaned it both times, no resultant leaks occurred). The house is 100+ years old, hugely refurbed so it's a very nice rental, 4BR with 2-car garage and attached MIL-type apartment but has not been fully replumbed. City water in that neighborhood is noticeably hard and the lines are also aged. Sediment loosens each time the water is turned off/on or if the city repairs a leak somewhere in the system.

Post# 1021473 , Reply# 8   1/16/2019 at 23:33 by SudsMaster (East of SF, West of Eden, California)        

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Well the good news today is that the replacement check valve arrived in the post. It's an easy install, just remove the cover over the drain pump impeller, and insert the new rubber flapper. I'll try to post a photo of it. After that, got excited to test it out, so I ran a quick wash (40 min) and sure enough at the end of the cycle, the water had been pumped out down to the level of the impeller. Even better, the glassware in the test wash is basically spot free.

I am putting off installing the new inlet valve until Thurs or Friday. I'm hoping I can do it with the DW in place; but it will be uncomfortable and it's right down at floor level and the inlet hose doesn't have a lot of slack. Worst case is I have to pull the DW. Been there, done that. At least next time I'll remember to retract the front leveling feet to make it a bit easier (LOL). I didn't last weekend because they didn't look extended. But they were.


Same thing here. Water supply to the house is copper from the meter (used to be steel, but was replaced shortly after I bought the house because the line under the front yard had started to crumble. When I went to turn off the water main valve at the front of the house to work on something inside the house, the pipe for the shutoff valve moved like it was made of putty. Well, that was about 20 years ago. It got replaced with nice copper, under the front lawn, but the line to the water heater is still steel, There is copper under there, mainly to go to newer (prior to my ownership) connections like the laundry closet off the kitchen, and the master bath at the rear of the house.

Along the way I accumulated enough copper to replace the steel piping under the house. I just haven't got around to it. It may be a retirement project... if I ever retire. I do get tired of having to clean rust particles out of faucet screens etc, though. I could always hire a plumber, though ;-).

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