Water Hardness And Dishwashing - Fisher & Paykel DW60FC1 Service Manual

5.7 Water Hardness and Dishwashing

Hard water is water with a high concentration of minerals such as calcium and magnesium. In soft water,
this concentration is low. Water hardness varies by geographical location.
How does water hardness effect dishwashing?
Hard water can be detrimental to the performance of a dishwasher. Over time glassware washed in
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hard water will become opaque and dishes will become spotted or covered in a white film. Washing
in very hard water can cuase parts in the disheasher to fail over time.
Naturally soft or softened water has no detrimental effects if used witht he correct amount of
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detergent. However, excess detergent combined with hot, soft water may cause irreversible etching
to glassware. Etching forst appears as a rainbow-coloured film and if allowed to continie, can make
glassware permanently opaque.
How can you minimise any detrimental effects?
Contact the local council to find out about the water hardness in the area.
If the house has a hard water supply....
Advise the customer to increase the amount of detergent being used.
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Ensure the customer is using a detergent with a high phosphate content. Phosphate softens the
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water and this improves wash results. The customer could try using multi-purpose tablets which are
also designed to work in hard water areas.
Ensure the customer is using rinse aid, and the rinse aid setting is adjusted to setting 5 to help
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improve wash performance.
Advise the customer to use a dishwasher cleaner/descaler regularly, which will help remove
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limescale deposits in the dishwasher.
If the house has a naturally soft water supply....
Advise the customer to avoid using too much detergent. Advise the customer to follow the set
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instructions in the user guide on detergent quantities.
Ensure the dishwasher is not overloaded and water can reach all the dishes within the dishwasher.
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IMPORTANT!
If the water hardness supply to the dishwasher is above 250ppm/14.6gpg, then F&P suggest to fit a
household water softener to the incoming water supply. This will ensure optimum performance of the
dishwasher.
5 OPERATION
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