Hotpoint Ultima FDW85 Service Information page 11

Rinse Aid Warning Indicator
Situated next to the salt indicator, illuminates when the rinse aid reservoir requires refilling.
The turbidity sensor achieves the detection of rinse aid, utilising the same principle as soil level
detection.
The final rinse water is measured 5 seconds before the rinse aid is dispensed and another reading
is taken 1 minute after the rinse aid has been dispensed, The two readings are compared. If the value
is different the rinse aid warning indicator is turned on at the end of the cycle, alerting the user to refill
the rinse aid compartment.
Half Load Button
When selected allows the upper or lower basket to be selected to enable the half load feature. When
selected, the half load LED illuminates on the LCD display.
The half load feature should be selected before setting the main wash programme.
Softener Unit
Situated on the base of the dishwasher, water is fed from the air break unit into the base of the
softener unit containing the sodium charged ion resins which remove calcium from hard water.
The softened water now exits from the softener into the sump. After a number of fills in hardened
water areas the softener resins become saturated with calcium ions and are unable to absorb any
more. Consequently, further softening is not possible and for this reason it is necessary to wash the
resins in a saline solution at the end of the final rinse cycle.
When the regeneration solenoid is activated, the water that is held in the air break unit (200 ml) is
gravity fed into the salt container, displacing the water already in the salt container.
An amount of saline solution to be flushed through the softener unit will be predetermined by the
setting of the Water Hardness Adjuster. The displaced water runs into the resin container to
regenerate the resins. The ionic exchange lasts between 20 - 25 minutes. Two resin washes will then
be performed. 1 litre of water is filled. This removes the salt water from the resins. This is then
pumped out and a further 1 litre of water is filled to repeat the process.
High Pressure Sensor
Mounted on the sump adjacent to the filters, it consists of a microswitch connected to a diaphragm
that is activated on contact with water. When the water pressure flowing through the filters in the
dishwasher falls below the level required to wash efficiently (below 0.15 bar) the microswitch opens
sending a signal to the control module. this activates the filter cleaning procedure.
Filter Cleaning Procedure
The dishwasher has a special feature that will clean the filters if a blockage is detected.
NOTE: - This feature only applies to the Intensive, Normal and Eco wash programmes and
may extend the programme time by up to 40 minutes.
The filter cleaning procedure can be initialised in two ways.
1. If the Pressure Switch contacts do not close after the initial 2 litre fill via the water turbine.
2. During circulation if it is detected that the Pressure Sensor contacts are open.
The principle of the filter-cleaning programme is to fill the dishwasher with a greater amount of water
than in normal use (up to 6.5 litres).
The circulation motor and heater are then pulsed Off and On. This breaks up the food debris blocking
the filters allowing it to be pumped away.
The filter cleaning sequence checks at the hot rinse step of the filter cleaning programme the state
of the pressure sensor contacts. If the contacts are closed then the filter clean will complete and then
the selected programme will resume. If the contacts are still open, then the hot rinse is repeated.
If after this second hot rinse the contacts are still open, then the programme ends and displays the
blocked filter alarm on the console.
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