Water Softener (Where Fitted); Delivering Softened Water; Regeneration; Salt - Fisher & Paykel DishDrawer DD24D Series Service Manual

599735A
3.12

Water Softener (Where Fitted)

The Water Softener uses a softening material (resin) to prevent most of the elements that cause
hard water from being present in the wash water. The resin can only treat a limited amount of
water before it needs to be regenerated. Regeneration is achieved by pumping salty water (brine)
through the resin, and flushing away the hard elements to the drain. The process of delivering
softened water, and regeneration of the resin, is controlled by the electronic controller.
3.12.1

Delivering Softened Water

Supply water arrives from the inlet valve, then through an inline strainer to remove large deposits.
The strainer is attached to the water softener by an inlet spigot.
Water softener
In the water softener, the water passes through an air break and a diverter valve. It is then either
directed through the resin to the dispenser as softened water, or directly to the dispenser, then into
the tub. The electronic controller measures the volume of treated soft water, and adds an
appropriate amount of non-treated hard water, to deliver a mix that is at the required hardness
according to a pre-determined schedule. Water is treated according to its supply hardness. The
customer is able to select one of 5 supply hardness settings in option adjustment mode.
3.12.2

Regeneration

Regeneration is triggered when the amount of water that has been treated since the last
regeneration nears the capacity of the water softener. The quantities treatable for each of the five
settings of supply hardness have been predetermined, and are stored in the electronic controller.
When triggered, immediately after filling for the main wash, the brine pump is activated and
delivers a volume of salty water into the resin, at an amount appropriate to the hardness setting.
The frequency of the pump is 3 Hz, and makes a slight rattling sound. Later in the wash cycle, the
resin is flushed with supply water, and the by-products of regeneration are delivered into the wash
water, and drained with it away as waste. During the flush, the fill valve turns on and off alternately
for 5 seconds for a number of times depending on the hardness setting. Normal treatment of
incoming water then resumes.
3.12.3

Salt

The customer is required to fill the salt tank with dishwashing salt from time to time. Salt is used in
the water softener by mixing it with water to produce the salty water (brine) used in regeneration.
When the salt level is low, a salt level detector causes a glowing red LED to appear in the salt
bung, and a "Salt" symbol appears in the LCD, if one is fitted. When this happens, the customer
should remove the salt bung, and using the salt container provided, pour salt into the salt reservoir
until salt can be seen at the opening. The "Salt" symbol on the LCD will disappear and the red
light will not be visible when the salt tank bung is replaced. In areas where the supply water is
moderately hard, 21 dH (degrees of hardness) or 375 parts per million, water softener setting 3)
the salt reservoir will need to be filled about once a month, and in harder areas more frequently.
Delivery of treated water from one fill of the salt reservoir:
240 litres at 30 – 100 ppm from 375 ppm supply water (setting 3)
144 litres at 30 – 100 ppm from 625 ppm supply water (setting 5)
spigot
20
NOTE: The strainer
is a replaceable
part, and must be
replaced if blocked.