Cycle Times/24-Hour Ice Production/Refrigerant Pressure Charts - Manitowoc Indigo Series Technician's Handbook

Cycle Times/24-Hour Ice Production/
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 2 - 3 minutes faster,
depending on model and ambient temperature.
• Regular cube production derate is 7%.
• 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.
• Refer to "Symptom #2 - Operational Analysis
Table" page 144 for the list of data that must be
collected for refrigeration diagnostics. This list
includes: before beginning service, ice production
check, installation/visual inspection, water system
checklist, ice formation pattern, safety limits,
comparing evaporator inlet/outlet temperatures,
discharge and suction pressure analysis.
• Zero out manifold gauge set before obtaining
pressure readings to avoid misdiagnosis.
• 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 water pump energizes.
• 50Hz dice and half dice production derate is 12%.
• 50Hz regular cube total production derate is 14%.
Part Number Preliminary 6/11
Charts
307