Bosch Dishwasher - Clean Metering Tank?

[daveb99]

I have a Bosch integrated dishwasher (SMV50C00GB) which is about 5 or 6 years old.

It completes the cycle perfectly but we have a small amount of water that ends up under the dishwasher after every cycle (i.e. in the tray that also contains the anti-flood float and switch).

I have traced it to what appears to be the overflow in the metering / fill tank, on the left hand side of the dishwasher. There are 3 areas of the tank that look like they have filled up with 'gunk' and I think this is what is causing the overflow to be in use - albeit it's only a couple of teaspoons worth of water per cycle.

So, rather than buy a new dishwasher, which seems rather OTT to fix this (!) I'd like to perhaps try and remove the metering tank and attempt to clean it out.

I have added some photos below.

1. Metering tank. Overflow is on the left side of it.

2. Upturned 'U Bend' (waste flows right to left) showing the 1st blockage (above it).

3. 2nd blockage - higher up

4. 3rd blockage (small).

Is the metering tank something that would be cleaned/unblocked sufficiently if I use a good dishwasher cleaner liquid/powder on a full cycle? We have never used cleaner, nor any salt, since our water is quite soft. Would it be wise to start using salt?

If I want to remove the tank to try and clean it, it looks like there are a couple of retaining clips either side (grey clip on picture 4 above) which would need releasing after pulling out the drain and feed hoses (O-ring seals)? Is it common to remove this tank and refit it easily? What's the best way to clean it thoroughly and remove all the blockages?

I've also noticed a lot of crystallised orange material in a larger tank underneath - shown in this photo - is this normal?

Any help would be much appreciated - I'd rather not buy a new dishwasher because of this, but will do if there is too much to sort out (the tank containing the orange stuff looks impossible to get out, for example!).

 

[daveb99]

Anybody?

 

[daveb99]

Can anyone offer any advice or guidance ?

 

[c8lzero1980]

I have the exact same problem - did you manage to fix this?

I've removed the plastic matrix, there are two plastic components on the inside left of the dishwasher one near the base and the other half way up. Once removed you can also unclip the metal clip on the water inlet and disconnect the grey wire. It should then just pull out of the other hoses. I've cleaned it but can still see gunk around the black float at the top left. I also have the orange stuff - no idea what that is?

 

[mr_chaela]

I had the same problem with a Hotpoint dishwasher (similar matrix to the Bosch). Tried all sorts to clean it out, only thing that worked was strong bleach. The gunk at the top - 3rd photo - is biological, something like algae or mould slime. The bleach killed it and eventually cleared it out, took a long time though, had to leave it overnight then continual flushing till it dislodged and washed out.
Have fun

 

[dishman]

Yes, I repaired this very issue on two dishwashers recently....

Have you run the cycle and identified where the leak is actually coming from?

The gunk in that top section should not actually be the cause of the leak, this is just a result of gunk backing up when it drains. Those chambers are designed to act as a pressure release vent/valve when it drains (I assume to prevent some kind of pressure lock). But, even if it is a bit blocked, it should not be the cause of the leak. I have seen much worse blockages, and they have never been the cause of the leak.

The leak is probably the to o-rings just to the left of that printed serial number "9000632599". When you have it running, you may notice it dripping at these points. If you put a sheet of paper towel around this area and run the machine, you may see it slowly start to absorb water. That is if you cannot be bothered watching it and looking for drips.

Can you confirm this is the case?

----

You have two choices.

1) (quick method) Remove the whole matrix unit and repair the leaky o-rings (if it is them). Put it back. That should fix the leak.

2) (more thorough) Remove the whole matrix, and flush it through with hot water. Bleach is not really required, and may be a bit strong. Sterilizing fluid is a very dilute form of bleach and is acceptable. But, I found that constant flushing with hot water worked best.

The second option may take longer as the gunk could be pretty solid in that maze area of the matrix. I spend a good few hours filling the matrix with hot water from the bath tap and shaking it from side to side. On the second dishwasher I did this with it dislodged the dirt much quicker. This was because bosch had redesigned the maze area to make it less restricted. Sot he dirt flushed out very quickly.

P.S - Don't worry about that orange crystalline section. It is normal and meant to be there.

 

[JEBski]

Yes, mine was the same.
I removed the matrix and cleaned with kettle descaler.
Its necessary to decant the descaler solution and re-heat to boiling using a microwave oven.
Took some time but even the black float thingy came out spotless.

Have no clue what the orange solution is in the tank.
Would appreciate if someone could advise what it is and how to remove it or get it clean.

Would also appreciate if anyone has got a flow diagram.

 

[dishman]

The orange crystalline section is perfectly normal. It is water softener resin and indicates all is working correctly. If it were black or any other colour, that is when you should be concerned. You don't need to clean it or remove it and replace it. Just ensure the softener tank is topped up with salt as it should be.

 

[JEBski]

Thanks dishman.

Cycled the rinse program about 5 times and things seem to [almost] returned to normal.

Almost means the machine seems to cycle properly but is accompanied by a constant beep. I am speculating that means there is a fault but without an error code, I'm a little stumped. The light indicating supply water fault is on; the water end has been checked and confirmed OK.

Again, I'm guessing the cable relays any problem back to the control panel so that would mean there is no requirement to check the machine end.

I'll save that job for tomorrow, after all what else would one do during a heat wave!!

 

[dishman]

@JEBski

What is the make? Bosch?

What happens when you run a normal programme (not just rinse)?

When does the beep occur? What point in the cycle? Does the water get hot? Is it draining properly?

 

[JEBski]

Hi dishman
The machine is a Bosch SMV53A.
It beeps continuously on the 2 cycles that I've tried, I.e. Rinse and auto.
Does the water get hot - no idea, its not yet been properly tested yet. I ran the rinse cycle to check the original error code [E15] had cleared.
The good news is that its draining properly, the original error code was E15. That is now solved [hopefully].

The display illuminates the tap [water supply], the salt requirement, and the third [can't remember]. There is no error code. So, the plan was to clear the inlet water code with the hope that it would resolve the other issues. Very little logic to the diagnosis [at the moment] which is why I was looking for a schematic diagram.

 

[dishman]

Hmm - beeping continuously from the start?

Have you run it with the sides off to check how well it feeds the water? If this is a more modern dishwasher that does not store water in tanks on the sides, then it could be a water pressure alert.

Is the tap open full? Have you checked the connection from the hose to the tap, these have a little filter in normally, check it is clear of debris.

If it detects there is a fault with the heating element, it could be trying to tell you it won't heat. But, normally you can tell by opening it mid-cycle and seeing if the water is hot on a normal auto wash. You should also be able to feel the warmth on the dishwasher.

 

[JEBski]

Hi dishman
The sides were off during 3 or 4 rinse cycles and all appeared OK with water flowing into the sprays and returning/discharging to drain.

I checked the inlet filter/strainer and there is both plenty of water and pressure. Have also cleaned the strainer [which was already clean and not blinded]. Have not checked the volumetric flow rate with a bucket and stop watch but the same pipe branch delivers water to the outside hose and that pressure was sufficient to blow off the hose connector! So consider the pressure is OK. The issue here is that whilst I'm confident there's sufficient flow and pressure it begs the question of why the "tap" symbol is illuminates [which is indicative of low pressure/low flow], hence my focus for tomorrow for eliminating that symbol in the apartment screen.

I've not rechecked the heating element. I am guessing that you're suggesting the beep is a result of a fault which is possibly from a failed heater and that suggestion is based on the most frequent/common problem.

 

[JEBski]

Sorry, predictive spelling has changed a couple of words.
"that symbol in the apartment screen." should read "alarm screen

 

[JEBski]

Calling Dishman
I think the problem is diagnosed. I would like to say solved but only time will tell.

The m/c was left unplugged overnight.
In the morning, the water alarm was not illuminated I assume it had reset. The m/c was started and again the beeping started and the water alarm illuminated.
I disconnected the water supply; the strainer was still clean, started the m/c disconnected from the water and the large water connector started vibrating. [Is this a solenoid designed to cut off the water if the leak detector initiates and was it stuck?] Looked inside the machine and all was dry.

Turned the m/c off, tapped the solenoid, reconnected, restarted and hey presto, back to normal. No beeps, cycling properly and heating.

So, I would conclude that the defect is the water connector. Exactly what it does, and what is inside is not known to me but everything is pointing to that thing being a solenoid valve.

I'd like to thank you for your support, thoughts and comments.