Scotsman CU0415 - Manual (Page 15)

Service Manual for Models CU0415, CU0715 and CU0920
August 2013
Page 14
Electrical Sequence
Proper voltage must be supplied and the bin
thermostat closed and calling for ice or the control
system will not have power.
Initial power up: Moving the master switch from OFF
to ON starts the machine in a harvest mode, the
compressor is operating with the inlet water solenoid
valve and the hot gas valve energized, water enters
the machine at the top of the evaporator, flowing down
into the reservoir.
After a set time of 2 minutes the inlet water valve
shuts off, the hot gas valve closes and the pump,
compressor and fan motor start operation. A blue light
indicates the freeze cycle mode.
Early in the freeze cycle, when the reservoir water
temperature falls enough to cause the resistance of
the water temperature thermistor to change to a pre-
set point, the controller will shut the water pump off for
30 seconds. When it is shut off a red light on the back
of the controller will be ON.
As the freezing cycle continues the suction line
temperature will fall, changing the resistance of the
thermistor attached to it. At a pre-set resistance a
timer in the controller will start to finish the freezing
cycle. A yellow light switches on and the freeze cycle
will continue for 7 more minutes.
The Harvest or Defrost mode begins. The yellow and
blue lights switch off. The pump and fan motor switch
off. The hot gas valve and inlet water solenoid valve
are switched on. The compressor is on any time the
unit is in ice making mode.
Harvest continues until the thermistor attached to the
suction line warms up, changing its resistance to a
pre-set point. At that time the yellow timer light will
switch on. Harvest time equals the minimum harvest
time plus the time it takes to change the thermistor’s
resistance plus a final timer. When all timers are
satisfied, harvest is complete and the freeze cycle
restarts.
The unit will shut off any time the bin thermostat is
open, including while the unit is in a freeze or harvest
cycle.
Unit in ice making mode, freeze mode indicator light
is on.
Unit in ice making mode, timer indicator light is on.