Manitowoc Marine Q 1000, Service Technician'S Handbook

Page: 87 / 179

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Safety Limits
GENERAL
In addition to standard safety controls, such as high
pressure cut-out, the control board has two built in
safety limit controls which protect the ice machine from
major component failures. There are two control
boards with different safety limit sequences. Original
production control boards have a black micro-
processor. Current production and replacement
control boards have an orange label on the control
board microprocessor.
Safety Limit #1: If the freeze time reaches 60
minutes, the control board automatically initiates a
harvest cycle.
Control Board with Black Microprocessor
•
If 3 consecutive 60-minute freeze cycles occur,
the ice machine stops.
Control Board with Orange Label on
Microprocessor
•
If 6 consecutive 60-minute freeze cycles occur,
the ice machine stops.
Safety Limit #2: If the harvest time reaches 3.5
minutes, the control board automatically returns the
ice machine to the freeze cycle.
Control Board with Black Microprocessor
•
If three consecutive 3.5 minute harvest cycles
occur, the ice machine stops.
Control Board with Orange Label on
Microprocessor
•
If 500 consecutive 3.5 minute harvest cycles
occur, the ice machine stops.