Scotsman CME506R AutoIQ - Manual (Page 20)

Technicians Only: Freeze Cycle Operational Sequence
Assuming the machine has been operational, the
Freeze cycle begins with the end of the Harvest
Cycle:
• Water level overflowing
• Water Inlet Valve is OFF
• Water Pump is ON
• Liquid Line Valve is OPEN
• Pump Down Control is CLOSED
• Compressor is ON
• Hot Gas Valve is ON (plus 5 seconds after
start of Freeze on D series)
AutoIQ Controller Operation, Beginning
freeze:
1. Switches on Freeze indicator light and shuts off
the hot gas valve.
2. Measures and stores the discharge
temperature.
3. If the discharge temperature exceeds the design
maximum, shuts the machine down on a
Refrigeration Error.
4. Checks for a “bin full" signal throughout the
cycle.
5. Measures the reservoir water temperature. If the
machine is operating correctly, the reservoir water
temperature will fall at a standard rate. The AutoIQ
Controller will be checking to see if the water
temperature fall matches that rate.
If not, it re-checks the discharge line temperature.
If too low, it Shuts Down on a Refrigeration Error. If
the discharge temperature is acceptable, the water
system is checked by shutting off the water pump
and determining if the water level goes up enough.
If it does not, the inlet water valve will open again
to fill it. If, after restarting, the water level does not
drop, it is assumed that there is a water pump
problem and the machine Shuts Down on a Water
Error.
If the water level does “measure up" the water
pump is restarted and the AutoIQ Controller then
measures how long it takes to lower the water
level. If the water level does not fall, the machine
Shuts Down on a Water Error.
6. Once per freeze cycle the machine may shut off
the water pump. It only does this when the water
temperature reaches a preset minimum. The pump
will only be off for a few seconds. After the pump
restarts, the inlet water valve will open to refill the
reservoir.
7. As the machine makes ice, the water level in the
reservoir will ultimately fall to the Harvest Level.
Note: If the freeze cycle exceeds the preset
Maximum, the AutoIQ Controller will Shut Down on
a Refrigeration Error.
8. The end of Freeze cycle will see the machine in
this state:
• Water level = below harvest position
• Water inlet valve will be off
• Water pump will be ON
• Compressor will be ON
• Hot gas valve will be off
At this point Harvest begins and the AutoIQ
Controller switches the Harvest indicator light ON.
Note: If there is a power interruption, the machine
will restart and go thru a Harvest cycle.
CME506R, 656R, 806R: AutoIQ Cubers
January 2000
Page 20