Overfreeze Detection Control; Anti-Slush Control - Hoshizaki KM-230BAJ Service Manual

S2 Dip Switch Setting
No. 4
OFF
ON
11. Overfreeze Detection Control (S2 dip switch 5)
Do not adjust. This must be left in the factory default position or the unit will not operate
properly.
It is deactivated on the KM-230BAJ and KM-300BAJ/BWJ.
When activated, the thermistor detects the temperature of the evaporator outlet to find
overfreeze in a harvest cycle and at the beginning of a freeze cycle. If the difference
between the maximum temperature after the harvest pump timer starts counting and the
temperature at the end of a harvest cycle is 7.2°F (4°C) or more and if the temperature
at the end of a harvest cycle is 48°F (9°C) or less, the harvest cycle is extended for 30
seconds. If the difference between the temperature at the beginning of a freeze cycle
and the minimum temperature after 30 seconds in the freeze cycle is 2.5K or more
and less than 3.5K, the next harvest cycle is extended for 30 seconds. If the above
conditions occur in succession, the number of occurrence times 30 seconds will be
added to the harvest cycle time. If the above temperature difference is 3.5K or more, the
freeze cycle ends after the minimum freeze cycle time and a harvest cycle starts.
If the evaporator outlet temperature is more than 3.5°C but not more than 5°C at the end
of harvest cycle, the harvest cycle is extended for 50 seconds before moving on to the
freeze cycle. If the evaporator outlet temperature is 3.5°C or less, another harvest cycle
starts. The harvest cycle does not repeat more than three times. The freeze cycle starts
even if the evaporator outlet temperature is 3.5°C or less at the end of the third harvest
cycle.
S2 Dip Switch Setting
No. 5
OFF
ON
12. Anti-Slush Control (S2 dip switch 6)
Do not adjust. This must be left in the factory default position or the unit will not operate
properly.
When activated (Ver. 1.1), the thermistor located on the suction line checks for a 41°F
(5°C) temperature as the evaporator cools. When 41°F (5°C) is reached, a 4.8 kΩ signal
causes the control board to de-energize the pump motor for 10 seconds.
When activated (Ver. 2.0), the thermistor located on the suction line checks for a 50°F
(10°C) temperature as the evaporator cools. When 50°F (10°C) is reached, a 3.9 kΩ
signal causes the control board to de-energize the pump motor for 10 seconds and
energize it for 50 seconds repeatedly. When 34°F (1°C) is reached, a 5.9 kΩ signal
causes the control board to de-energize the pump motor for 10 seconds, energize it for
50 seconds, de-energize it again for 10 seconds, then energize it continuously.
Harvest Completion
Detection Control
Deactivated
Activated
Overfreeze Detection
Control
Deactivated
Activated
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