Some washing machine manufacturers are extra cautious with regard to softened water. Miele in particular write about this in their guidance. The issue is in fact regarding detergent dosing.
When you are using softened water, you should cut down the amount of detergent you use by 75%. You also do not need to add any fabric conditioner. Simply doing this eliminates any chance of overdosing on detergent (not to mention saving you money!) In fact, we make a specialised washing powder designed for use in washing machines supplied with softened water. Following the guidelines on this pack means you will always get the perfect dose when using softened water – with any machine.
Recently we advised one of our customers on this issue, as they have a Miele machine. They wrote to Miele to enquire as to why they should not use softened water and received the following response:
“Many of our customers make use of domestic water softeners, which gives them the benefit of a softened water supply. We can confirm that whilst there are issues to take into consideration when connecting any washing machine to a water softener, as long as these are adhered to, this will not affect the performance or durability of the appliance and will not invalidate your extended guarantees, providing any future faults are not caused by the water softener. If using Miele TwinDos detergent dosing, you need to follow the commissioning section in the instruction manual and set the washing machine for the softest water level available. Normally Ultra Phase 1 Hardness level 1. This may be different for specific models, please check your actual manual for model specific settings. ” Customer Support Advisor Miele
As an added bonus, you will find that washing your clothes with softened water in fact has many other benefits aside from savings on detergents and conditioners. Your clothes will be cleaner and brighter and your washing machine will be protected from scale and scum.