Insights into the Operation of the Scotsman Ice Cuber during the Harvest Cycle
A technical overview of the operational sequences of Scotsman AutoIQ™ Cubers models with particular emphasis on the water system and ice harvesting process. The content breaks down complex system operations into understandable steps, detailing the conditions under which the machine shuts down and how it restarts in case of errors. It outlines the intricate processes and system checks that occur during the freeze cycle, the harvest cycle, and even at startup after a power interruption. The Controller’s role in monitoring and adjusting operations to maintain optimal performance is explained in detail. Note the explanation of diagnostic lights and manual resets, demonstrating how the machine responds to malfunctions. The machine’s design to ensure continuous operation, even during challenging situations such as a lack of water, is also highlighted. This text is especially valuable for technicians who must understand the machine’s operation and troubleshooting processes effectively.
The harvest (not a defrost!) cycle is designed to minimize melting of the ice produced on the evaporator as it is ‘harvested’ and dropped into the ice storage bin.
Harvest Cycle
What happens during the harvest cycle of an AutoIQ™ Cubers model?
During the harvest cycle, the air-cooled model’s fan is switched off while the water valve opens to fill the reservoir to its full level. The water pump is initially shut off but restarts in less than a minute. Ice falls from the evaporator(s), passing between the bin control’s electric eyes. The Controller monitors this process and keeps the machine in the Harvest Cycle until the ice no longer falls. This cycle is designed to ensure optimal ice production.
What triggers the start of the harvest cycle?
The start of the harvest cycle is triggered by the system controller at the end of each freeze cycle. This is part of the machine’s natural operation to maintain a steady supply of ice.
How long does the harvest cycle last?
The maximum length of the harvest cycle is 10 minutes. However, the actual duration may be shorter as the Controller monitors ice falling and terminates the cycle when the ice stops falling through the electric eyes.
What happens if no ice falls during the harvest cycle?
The machine detects a refrigeration error if no ice is sensed falling during the harvest cycle. The machine will shut down if a refrigeration error is produced in the next cycle. This mechanism is vital for maintaining the ice machine’s performance and integrity.
How does the machine respond to a water error during the harvest cycle?
If the Controller detects an overly long water refill time, it will shut down the machine due to a water error. However, the machine will attempt to restart after shutting down, with a 20-minute interval between restart attempts. This feature is designed to minimize downtime and maintain ice production.
What happens to the water pump if the machine stays in the harvest cycle longer than the regular cycle?
If the machine remains in the harvest cycle for longer than 6 to 9 minutes, the water pump will be switched off until the next freeze cycle. This control measure helps prevent damage to the water pump due to excessive operation.
How does the machine determine the length of the next harvest cycle?
The first harvest cycle after a restart is long to establish a baseline. The time it took to release the ice during this baseline cycle is then used to determine the length of the subsequent harvest cycles. This approach ensures efficient ice production based on real-time performance data.
What conditions cause the machine to shut down during the harvest cycle?
Several conditions could cause the machine to shut down during the harvest cycle. They include a lack of water, refrigeration, or two consecutive harvest errors. These safeguards are designed to protect the machine from damage due to operational errors.
What happens when the bin is full, and the unit is in a harvest cycle?
The water pump is switched off when the bin is full and the unit is in a harvest cycle. This precaution prevents overflow and potential damage to the unit.
What changes were made to machine harvest cycles built after August 1996?
Changes in the harvest cycle in machines built after August 1996 include the water pump being switched off if the machine remains in the harvest cycle for longer than 6 to 9 minutes. Additionally, the last harvest cycle before shutting off on Bin Full has been shortened to 4-6 minutes. These changes were made to increase efficiency.
Refrigeration System During Harvest Cycle
What role does the refrigeration system play during the harvest cycle?
The refrigeration system plays a crucial role during the harvest cycle of an AutoIQ™ Cubers model. This system initiates the transition between the freezing and harvest cycles by opening the harvest solenoid valve, introducing hot gas into the inlet of the evaporator (s), and releasing the ice from the evaporators.
How is the refrigeration process reversed?
During the harvest cycle, the solenoid valve is energized. This redirects the hot gas refrigerant from the compressor directly into the evaporator. The increase in temperature causes the ice to loosen from the evaporator’s surface, initiating the ice harvesting process. This redirection of hot gas is the key element in reversing the refrigeration process. The harvest cycle continues until the Controller determines that all ice has been harvested, initiating the freeze cycle.
How does the refrigeration system respond if no ice falls during the harvest cycle?
If no ice falls during the harvest cycle, the refrigeration system and the machine detects a refrigeration error. If the error persists in the next cycle, the machine, including the refrigeration system, will shut down.
What role does the refrigeration system play in preventing damage to the machine during the harvest cycle?
The refrigeration system helps prevent damage by promptly addressing operational errors. If a refrigeration error is detected, it triggers a shutdown, thus safeguarding the machine’s integrity.
What happens to the refrigeration system when the machine shuts down due to a water error during the harvest cycle?
The refrigeration system also halts when the machine shuts down due to a water error. The machine, including the refrigeration system, will attempt to restart after the shutdown, with a 20-minute interval between restart attempts.
How does the refrigeration system determine the length of the next harvest cycle?
The refrigeration system contributes to determining the length of the next harvest cycle. The time it takes to release the ice during the first cycle after a restart, which depends on the refrigeration system, is used to set the timing for subsequent harvest cycles.
What happens to the refrigeration system when the bin is full, and the unit is in a harvest cycle?
When the bin is full, and the unit is in a harvest cycle, the refrigeration system continues operating unless operational errors are detected. The water pump, however, is switched off to prevent overflow.
Throughout the harvest cycle, the sequence of operations progresses in a way that ensures efficient ice production while minimizing potential damage to the machine components. The cycle reverses the refrigeration process – the hot gas solenoid valve is energized, which diverts the hot gas refrigerant into the evaporator (frozen during the ice making process). The increase in temperature leads to the ice separating from the evaporator’s surface, marking the beginning of ice harvesting.
The system is equipped to identify and respond to operational errors. If no ice drops during the harvest cycle, a refrigeration error is detected, leading to a system shutdown if the error recurs in the next cycle. Similarly, if the machine identifies a water error, it will shut down, though restart attempts will follow after a 20-minute interval.
The duration of the first cycle determines the length of the subsequent harvest cycles after a restart. The refrigeration system plays a pivotal role in this process, as the time it takes to release the ice depends on its performance.
In situations where the ice bin is full, the machine will shut down.
Factory Service Literature
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