Scotsman NME1854 - Manual (Page 13)

NME1854 & FME2404
January 2000
Page 13
ELECTRICAL SEQUENCE
There are 7 indicator lights on the control board:
· WTR-OK (Water OK). Green. Normal =
Glowing. Glows when there is water in the
reservoir.
· PWR-OK (Power OK). Green. Normal =
Glowing. Glows when the control board has
power and is functional.
· Service. Red. Normally Off.
· Freeze. Red. Normally glowing when making ice.
· Bin Full. Red. Normally Off when making ice.
· LED1. White. Located next to the board’s
Compressor Relay. Normally Glowing when
making ice.
· LED3. White. Located next to the board’s Auger
Motor Relay. Normally Glowing when making ice.
If the machine is switched off at the mode switch,
but is otherwise ready to go, switching the mode
switch to ON does the following:
· The PWR-OK light glows.
· If there is water in the reservoir the WTR-OK light
glows.
· After 10 seconds the Freeze, LED1 and LED3
lights glow and the machine starts up.
Start Up:
· The compressor relay and auger motor relay
become energized, connecting power to the
windings of the auger motor and contactor coil.
· The contactor is energized, connecting power to
the compressor, and the compressor starts.
· As ice is made it passes between the ice level
sensors but because it is not a continuous stream
it only interupts the sensor’s infrared beam
momentarily. The bin full light remains off and the
machine stays on until ice builds up in the bin and
blocks the path between the sensors for 6
seconds or longer. When that occurs the bin full
light glows and the machine shuts down.
Shut Down:
· The compressor relay opens, LED1 goes out.
· The compressor contactor opens
· The compressor stops
· The auger motor stays on for 1 more minute,
clearing out ice in the evaporator, and then
· The auger motor relay opens, LED3 goes out and
the auger motor stops.
The compressor will not restart until 2 minutes or
more have passed after the last shut down.
If the path between the ice level sensors remains
clear for more than 10 seconds the ice machine will
restart.
Control Board Protection Devices
· When the water level in the reservoir falls below
the water level sensor’s tip, the WTR-OK light
goes out and the machine shuts down. When
water refills the reservoir the WTR-OK light glows
and the machine starts up again.
· If the auger drive motor current becomes
excessive the compressor and auger drive motor
will be switched Off and the Service light will
blink. The control board will restart the auger
drive motor in 4 minutes. If during the first 60
seconds after restart the auger motor current
stays within limits, the compressor is restarted
and the machine returns to normal operation. If
the auger motor’s current is excessive within 60
seconds after the restart, the process will be
repeated once more. If during that try the current
is still excessive the machine shuts down and
must be manually reset. The service light will
then be glowing continuously.
To Reset: Disconnect and reconnect power to
the ice machine.
Other Protection Devices:
· If the high pressure cut out switch opens the
machine will stop immediately. It will
automatically reset when the pressure falls below
its cut in point.
· If the low pressure cut out switch opens the
machine will stop immediately. It will
automatically reset when the pressure rises
above its cut in point.
· The mode (on - off) switch is the manual control
for the complete machine, but it is not a service
disconnect.