Manitowoc UG018A, Technician'S Handbook

Page: 91 / 136

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Cycle Times/24 Hour 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.
• Refer to “OPERATIONAL ANALYSIS CHART” 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, hot gas valve analysis,
discharge and suction pressure analysis.
• 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.
• 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.