Water Softener (Where Fitted) - Fisher & Paykel DishDrawer DD605 Service Manual

599447A

3.14 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.
Delivering Softened Water: - Supply water arrives from the inlet valve. In the water softener it passes through an air
break and a diverter valve. It is then either directed through the resin to the dispenser, or directly to the dispenser, then
into the tub. The electronic controller measures the volume of water treated, and adds an appropriate amount of non-
treated 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.
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 to 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.
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 light 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), 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)
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