Service manual

Section 7 Refrigeration System
Part No. 80-1206-3 7-29
Cycle Time/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.
• 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, suction line temperature check,
cool vapor 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.
• All pressure readings are taken at the ice machine
head section. Pressures taken at the condensing unit
will vary with line set length.
• 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.
• During low ambient conditions, it is normal for the
head pressure control valve to hunt (fluctuate up and
down) on CVD condensing units. Hunting varies by
model and ambient temperature, but generally
settles out within the first 6 minutes of the freeze
cycle.