Description

AQUASTILLA 12 water treatment and softening system

VIESSMANN AquaStilla 12 is a domestic water softener designed to reduce hardness by removing calcium and magnesium ions. Supplied as model 7691891, it is intended for household plumbing to protect boilers, heaters and appliances from scale buildup. Typical use includes improving soap performance, prolonging appliance life and reducing maintenance in residential systems – a modern solution to hard water problems, designed to improve quality of life.

It is recommended that the hardness of softened water remains within 3–6 °dH (German degrees), and for copper installations, within 4–8 °dH.

How does the Aquastilla 12 work?
The unit is installed at the point where cold water enters the building. Hard water flows into the system through the main supply pipe and passes through the softener, where it is treated by an ion exchange resin (Purolite C100E). During this process, hardness-causing ions are captured and replaced with sodium ions, resulting in softened water that is then distributed throughout the home.

Once the resin’s ion exchange capacity is exhausted, the system automatically regenerates using a prepared brine solution. This process restores the resin’s effectiveness, allowing it to continue softening water efficiently.

Regeneration is triggered automatically every 14 days or after approximately 2 m³ of water usage. Each regeneration cycle uses about 1.5 kg of salt and up to 120 litres of water. A full refill requires 10 kg of tablet salt. The regeneration process does not interrupt water availability.

The ion exchange resin should be replaced after at least 10 years of operation (this period may vary depending on usage conditions).

Functions 

• Anti-flood protection: possibility of setting the maximum time of each opening of the water intake in the building and/or the maximum instantaneous flow of cold water, after exceeding which the station automatically closes the water supply to the building installation
• Vacation mode
• Possibility to set the head in the closed position
• Dry brine tank 
• Salt level alarm 
• Service alarm informing about the need to perform periodic servicing of the device 
• By-pass as standard