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Hiyas,
Just been reading a few posts in the public section and 3/4 in tablets were being discussed. This got me wondering as to why they put salt in them. I suppose it has a slight softening effect but I can’t see what good it really does for the machine.
As I understood it water enters the system, passes through the water softening unit and the impurities (lime or whatever) were filtered out, thereby softening the water. At the end of the cycle salt water was then passed through the softening unit cleaning out the impurities and was flushed away out the drain, never actually used to wash at all. (At least, that’s what the Whirlpool bumf I’ve got says).
With tablets the softener unit never gets anything but water flushed through it (the washing/rinsing water has long gone as has the tablet) so the impurities/scale remains there. Hence the reason why some of the softener units seem to solidify.Or have I got this horribly wrong? 😯
Brian
Re: Salt in dishwashers
An explanation of how the softening system works is here
The newer tablets, 3-in-1 etc., rely on builders to remove the calcium et all and not salt.
If you get the chance DP the detergent training explains it a lot better, it’s hard to do without graphics.
K.
Re: Salt in dishwashers
Thank “k” that explains things a lot better
But dose anyone have a chart of water hardness for the areas in the UK?
So we know what settings we should be using on the salt dispensers?Re: Salt in dishwashers
If you ring your local water supplier they will be able to quote you your hardness reading.
Greg
Re: Salt in dishwashers
Just out of interest, having read the “How water softening systems in dishwashers work” link in Kens post there is one thing I am a bit fuzzy about.
I fully understand the process as explained except for the fact that when the calcium ions are attached to the resins, due to the resin having a greater affinity for the hardness ions, why under the regeneration process do the hardness ions let go to be replaced again by sodium ions to which the resins have a lesser infinity?Re: Salt in dishwashers
Hi Martin
It is all to do with the balance of the polarity of the ions (-ve or +ve charge). Initially (i think) the +ve charged sodium ions are attracted to the -ve resin. As the sodium is lost to the resin it becomes weaker (spent brine). When the Calcium ions contact with the resin having a stronger charge they adhere to the resin. The resulting imbalance of charge causes two sodium ions to be released this continues until the resin has no sodium ions left to exchange.
I am not 100{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} sure how the next bit works but presumably during regeneration when the saline solution is introduced to the resin, the abundance of sodium ions in contact with the resin causes them to adhere and the resulting charge imbalance repels the calcium ions from the resins surface.
Not perfect but its somewhere near.
Andy 😀
Re: Salt in dishwashers
andy2 wrote:
Not perfect but its somewhere near.Andy 😀
Sounds good enough for me, Cheers Andy.
Re: Salt in dishwashers
Kenny wrote:But dose anyone have a chart of water hardness for the areas in the UK?
A rough guide can be found on a pack of Ariel, for exact measurement you’ll need a hardness strip which you canpick up from an angling supplier I think.
K.
Re: Salt in dishwashers
Thats a good post andy and how the Monoblock functions, it seems top be a trend these days that the all singing dancin tabs do the job, but how could they ?
The resin would eventually become a solid mass preventing fill of the dishwasher ( which I have Seen ) and I advise my customers to fill the salt every ten cycles if the dishwasher is used once a day.
most of the indicators only flag up when the level gets very low by which time they could have doen ten more washes with low salinity. As for the tabs most people I come across are having washing problems of one sort or another and I always advise the rein- statement of a branded powder and rinse aid. They never seem to call back with further washing probs !
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