Merloni Elettrodomestici
DISHWASHER EVO3
Service manual
EN
03-05-20/0
27-54
Language Issue/Edition
Page
5.2
Normal turbine fill analysis
The fill logic is described in the diagram entitled
“Special Filter Cleaning
cycle”
.
The dishwasher fills water via the turbine directly and controls the pressure
switch. If the switch contacts should open during the two-minute control, the
dishwasher continues to fill until the maximum 6 litre level is reached.
The turbine fill method is different from the pressure switch fill because,
regardless of the specific flow rate of the mains water supply and how the
dishes have been loaded, the water fill rate is kept constant.
The fill process is as follows:
• Tub emptied in impulses until pressure switch contacts reset (fixed time): 1
min 20 secs and about 3/5 impulses depending on the time required for
the pressure switch contacts to reset)
• 2 litres filled between cycle (the tolerance level found in tests was +/-0.2
litres)
• Additional 2 litres filled in-cycle (with the wash pump on)
• Check status pressure switch (90 mbar)
• If closed, ok. Otherwise fill to 6 litres: if the switch closes before 6 litres all
is well. Otherwise the filter cleaning cycle will be run (if the switch doesn't
close it means the filters are clogged or the switch is broken).
• The filter cleaning procedure is a sequence of water fill and drain stages
and jog wash cycles that removes any blockage from filters enabling the
pressure switch to once again “feel” the water level.
5.3
Possible fill failures
Possible failures that may be encountered during water fill are linked to
components that may break after the fill control.
•
turbine broken:
in order to complete the cycle underway, the machine will
proceed as if the fill process was controlled by the pressure switch. At the
end of the cycle however, it will signal the turbine broken alarm.
•
pressure switch broken:
if the pressure switch breaks, the dishwasher will
signal the relative alarm at the end of the between-cycle water fill.
•
pressure switch and turbine both broken:
in this instance the dishwasher
loads a maximum 8 litres of water in a specific time interval (minimum
time required for pressure switch contacts to close at low pressure fill, 0.3
bars)
•
fill solenoid breaks when on:
in this instance the turbine can check if water
is being filled even when not requested: it generates the fill solenoid alarm
and will start draining the wash compartment for the duration of the alarm
(this works only when the machine is on; the double solenoid provides the
most safety).