Manitowoc STH042 4/16, Technician'S Handbook

Page: 127 / 146

Part Number STH042 4/16 127
Cycle Times, 24 Hr. Ice Production and
Refrigerant Pressure Charts
These charts are used as guidelines to verify correct ice
machine operation.
Accurate collection of data is essential to obtain the
correct diagnosis.
• Production and cycle times are for dice cube - Half
dice cube cycle times can be 1-2 minutes faster
depending on model and ambient temperature.
• Ice production checks that are within 10% of the
chart are considered normal. This is due to variances
in water and air temperature. Actual temperatures
will seldom match the chart exactly.
• Regular cube production derate is 7%.
• Refer to “Operational Analysis Chart” for the list
of data that must be collected for refrigeration
diagnostics.
• Zero out manifold gauge set before obtaining
pressure readings to avoid mis-diagnosis.
• Discharge and suction pressure are highest at the
beginning of the cycle. Suction pressure will drop
throughout the cycle. Verify the pressures are within
the range indicated.
• Record beginning of freeze cycle suction pressure
one minute after the water pump energizes.
• 50Hz dice and half dice production derate is 12%.
• 50Hz regular cube production derate is 14%.
Charts