Bosch SG569L12GB problem, pictures added

[Omar]

Re: Bosch SG569L12GB problem, pictures added

I’ve removed the matrix and pressure chamber. Is it safe to stick the pressure chamber under running tap water to clean it or are there any electrical components I need to be careful about?

[Martin]

Re: Bosch SG569L12GB problem, pictures added

No, as long as you remove the switches first it should be fine! 🙂

[Omar]

Re: Bosch SG569L12GB problem, pictures added

I tried to remove the pressure chamber to clean it but i found it too compicated and called the Bosch Engineer £107 charge in total, he fitted a new chamber.

If you look at my previous pictures, it shows the pressure chamber gunged up, I thought this was all food bits that had accumilated over 3 years. But the engineer said it is not food becuase only clean water passes through the chamber. He said the gunge in the pressure chamber was, what ever was in the main water supply i.e minerals etc. A build up of that.

Is the engineer correct?

[trikidik]

Re: Bosch SG569L12GB problem, pictures added

The Bosch engineer is indeed correct. Only clean water actually flows through this area. The gunk in this area is the same sort of gunk you find in washing machine dispenser tops (again only clean water enters this area). If the water from the tank did enter this area of the pressure chamber, then the detergent in the wash water would clear it away. The matrix does however get clogged up on the drain side (anti-syphon) due to greae deposits left over from the wash water. HTH 🙂

[CJAPeterborough]

Re: Bosch SG569L12GB problem, pictures added

An interesting question to which I have some ideas about?

The pipe from the pressure chamber runs directly into the sump without any kind of non return valve.

This pipe can be at at the lowest point of gravity in the system therefore if food deposits etc get past the filters they will settle in the pipe imho.

I agree that this pipe is regularly flushed but once the machine fills I think there is not much flow through it via the action of the main circulation motor.
Most of the flow will be from sump to spray heads and returned to sump.

I doubt that the clogging up is just caused by hard water action.
I have seen a few completely gunged up and foul smelling-certainly contributed to by other factors ie food deposits etc.

In reality I think it is a combination of the two.

It is a known weakpoint in the Bosch systems after all if it was just hard water action,
then the inlet pipe with the same flow characteristics would clog up also?

[Martin]

Re: Bosch SG569L12GB problem, pictures added

Omar wrote:But the engineer said it is not food because only clean water passes through the chamber. He said the gunge in the pressure chamber was, what ever was in the main water supply i.e minerals etc. A build up of that.

Is the engineer correct?

Based on what you say that he said then no that is incorrect.

If you study your last picture, the mains water enters the Pressure Chamber on the extreme left hand side (just left of the blue lever). Where the ‘clean’ water enters there is a slight but necessary air gap. Its purpose is to ensure there is no direct connection between the clean incoming water supply and the ‘grey’ soiled water beyond that point.

Hence the Pressure Chamber and attendant pipework beyond only contain grey polluted dishwater. The most destructive of which is fat deposits shown clearly stuck firmly in that chamber. Also if you look in the top left hand corner of the water inlet/drain matrix you will see that same build-up of fatty deposits stuck within the drain ‘anti-syphon’ part of that matrix. Clearing that build-up is far more difficult due to its almost impossible access and as a rule we (engineers) replace that whole unit when the anti-syphon system is badly compromised by such debris.

HTH?:D

[Omar]

Re: Bosch SG569L12GB problem, pictures added

another thing i forgot to mention is that under my sink the stop clock has a small leaver, when the leaver is in the 12 oclock position, then it is fully open hence full water supply to the dishwasher.

But the engineer found that the leaver on the stop clock was in the almost 3 oclock position (machine is 3 years old), he said that water supply to the diswasher was not fully open. That means, the stop clock has been like that since how long we have had the machine i.e 3 years.

If the water supply was not fully open for 3 years, could that explain all the gunge build up??

Also when putting dishes in the dishwasher should you rinse them under running tap water?

[Martin]

Re: Bosch SG569L12GB problem, pictures added

Omar wrote: If the water supply was not fully open for 3 years, could that explain all the gunge build up??

Not at all!

I explained in my previous post to you the difference between ‘clean’ incoming mains water and the ‘grey’ polluted water that lies below the water level. And that there is a subtle but significant ‘air break’ between the two. Dirty water is classed as grey and that manifests itself, in dishwashers anyway, into various colours of the rainbow brought about by fatty residues such as tomato paste, gravy, egg yolk, curry spices etc…all manner of yuck! Which is exactly what lies in the grey water area of your machine. Non of which comes from, or is connected to, the incoming water supply.

Omar wrote:Also when putting dishes in the dishwasher should you rinse them under running tap water?

That is an excellent idea and one which will dramatically reduce the pollutants placed inside the machine. Less grey water, easier, faster cleaning and with better results overall.:D

[Omar]

Re: Bosch SG569L12GB problem, pictures added

Martin wrote:

That is an excellent idea and one which will dramatically reduce the pollutants placed inside the machine. Less grey water, easier, faster cleaning and with better results overall.:D

Hi martin, if i had regulary rinsed the dishes in the sink, then would i have avoided my problem?

Finally, are other brands of dishwashers like AEG or miele vulnerable to this same problem.

[Martin]

Re: Bosch SG569L12GB problem, pictures added

Omar wrote:Hi martin, if i had regulary rinsed the dishes in the sink, then would i have avoided my problem?

By some margin but not entirely. Dishwashers clean dishes they don’t however clean themselves and at some point in time throughout their working life they will need cleaning too!

Omar wrote:Finally, are other brands of dishwashers like AEG or miele vulnerable to this same problem.

Indeed so. All brands have the same susceptibility.

[Author]

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