Bosch dishwasher problem

[google]

I have a Bosch and the salt light is always on too, even if it has salt.

Here is what i have learnt about our dishwasher, mainly from this group, but also from actually studying the operation of the machine.

• The salt is used to recharge a water softener. The first 'stage' of our dishwasher is to use a little water to desolve some salt and re-charge the softener. This water goes nowhere near the plates.

• The next stage is the pre-rinse, followed by an empty.

• Next the soap flap thing opens and the plates are washed and the water heated, followed by an empty.

• Next the plates are rinsed, with a little rinse aid.

There are still a few things I don't understand. One of them is a small opening on the salt container. Block this (say with a large chopping board), and a white deposit is left on everything after the wash. Is this because the water is softened by some water going into the softener here, or is the water softened on its way into the machine?

[Mary Fisher]

The vicar wouldn't allow me to say that so I said it sotto voce. And I've kept all my vows!

Mary

[Mary Fisher]

Ours is the Slimline 4302, we bought it in April 2001.

Thanks. I wasn't worried about it - but he was. It's being so happy as keeps him going ...

Mary

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[Mary Fisher]

Oh we still have it - I keep everything :-)

There's nothing about the light staying on in the (very helpful) trouble shooting section.

I think there's something missing from the beginning of your post ...

Mary

[Mary Fisher]

Briefly, salt dissolves the lime in the water - by ion exchange in the softener.

Well, there were mothers around, surely?

Mary

[Bob Eager]

But the salt doesn't do the softening,. That's my point. It merely recharges the ion exchange system, usually at the start of a cycle. That's why I don't see how salt in the wash water can soften the water.

[Mary Fisher]

The salt doesn't go into the wash water :-)

Mary

[Bob Eager]

It does if it's only in the tablets. Which was my original point.

[Guy King]

The message from "Mary Fisher" contains these words:

So how does it get from the tablet into the water-softener then? The softener is upstream of the washing compartment.

[Bob Eager]

This is exactly my point, but Mary either hasn't read the start of the thread, or she's forgotten.

[Mary Fisher]

Sorry, if I saw the word 'tablet' I switched off I guess. I don't know anything about them.

Mary

[Mary Fisher]

Ahem! Mary STARTED the thread :-)

It went its own way ...

Mary

[Andy Hall]

If you look at the box it says Salt *Action* not salt. Roughly translated this means that there is a chemical cocktail that does the equivalent of softening the water, but not using the ion exchange softener in the machine.

[Guy King]

The message from "Mary Fisher" contains these words:

Many tablets claim to have a "salt action". The question is whether this is a discrete water softening system that replaces the ion exchange system built into the dishwasher, or whether it's just salt - which can't possibly work as it never gets near the softening device to recharge[1] it.

[1] Well, discharge, really - it's full of all the wrong sorts of ions when it's been used and they need to be flushed out.

[Andy Hall]

That I don't know - I haven't done comparative tests.

The Miele dishwasher gets softened water from the main water softener in the house.

Tablets get used and to be honest, nothing else has ever been used except that the original 3 in 1 tablets now seem to be 5 in 1. The results either way are very good but I don't know whether that implies that 5 in 1 are better than 3 in 1 and no worse than putting salt in the machine itself.

Since a DW water softener uses so little salt anyway, it's almost academic.

[Bob Eager]

Aha. No-one said that! Since I never buy the tablets...

But that's what I was after finding out all along. I guess the question is whether this is as effective as the built-in softener.

[Pete C]

Hi,

Probably sodium carbonate/percarbonate in the tablets, a.k.a 'washing soda':

cheers, Pete.

[MB]

Salt binds lime and is supposed to prevent attachment of same to glass.

The man who sold me a Miele DW said that at a course he attended at the factory, he was told 3-in-1 tabs are not to be recommended. But why are tabs an option on the machine? I use them exclusively, and the "salt needed" light never lights up. Glass and everything else is clean as a whistle.

[Guy King]

The message from "MB" contains these words:

What utter nonsense.

Diswashers have ion-exchange water softeners, which remove calcium ions and replace them with sodium ions as the incoming water flows through the softener. Obviously this can't go on forever, so each time you switch the machine on it flushes strong brine through the exchange medium to remove the stored calcium ions and flush them down the drain, leaving the column charged with sodium ions to repeat the process.

The reason you need to do this in the first place is that calcium compounds leave white spots all over things as they dry, while sodium compounds are more soluble and generally don't.

The confusion over "salt action" tablets is that the water softening is a seperate process that takes place elsewhere in the machine well away from the washing compartment. There's no way anything in the tablets can get near the softening system so people doubt that it can work. I suspect it's not actually salt but a completely different softening process, probably involving sodioum carbonate.

Quite why anyone would want to replace a cheap and effective process built into your machine with expensive less effective tablets is another question.

[Mary Fisher]

Well, it's an easily understandable way of saying what happens for people who don't know about ions.

Mary