Discharge Line Temperature Analysis - Manitowoc S Service Manual

Section 7

DISCHARGE LINE TEMPERATURE ANALYSIS

General
Knowing if the discharge line temperature is increasing,
decreasing or remaining constant can be an important
diagnostic tool. Maximum compressor discharge line
temperature on a normally operating ice machine
steadily increases throughout the freeze cycle.
Comparing the temperatures over several cycles will
result in a consistent maximum discharge line
temperature.
Ambient air temperatures affect the maximum discharge
line temperature.
Higher ambient air temperatures at the condenser and/
or higher inlet water temperature = higher discharge line
temperatures at the compressor.
Lower ambient air temperatures at the condenser and/or
lower supply water temperature= lower discharge line
temperatures at the compressor.
Regardless of ambient and water temperatures, the
freeze cycle discharge line temperature will be higher
than 160°F (71.1°C) [S850/S1000 Air & Water Machines
Only - 140°F (60°C)] on a normally operating ice
machine.
Part Number 80-1480-3
Procedure
Connect a temperature probe on the compressor
discharge line with-in 6" of the compressor and insulate.
Observe the discharge line temperature for the last three
minutes of the freeze cycle and record the maximum
discharge line temperature.
Discharge Line Temperature Above 160°F (71.1°C) At
End Of Freeze Cycle:
Ice machines that are operating normally will have
consistent maximum discharge line temperatures above
160°F (71.1°C).
Discharge Line Temperature Below 160°F (71.1°C) At
End Of Freeze Cycle
Ice machines that have a flooding expansion valve will
have a maximum discharge line temperature that
decreases each cycle.
Verify the expansion valve sensing bulb is 100%
insulated and sealed airtight. Condenser air contacting
an incorrectly insulated sensing bulb will cause
overfeeding of the expansion valve.
Verify the expansion valve sensing bulb is positioned
and secured correctly.
S850/S1000 Air and Water Ice Machines Only:
Discharge Line Temperature Above 140°F (60°C) At
End Of Freeze Cycle:
Ice machines that are operating normally will have
consistent maximum discharge line temperatures above
140°F (60°C).
Discharge Line Temperature Below 140°F (60°C) At
End Of Freeze Cycle
Ice machines that have a flooding expansion valve will
have a maximum discharge line temperature that
decreases each cycle.
Verify the expansion valve sensing bulb is 100%
insulated and sealed airtight. Condenser air contacting
an incorrectly insulated sensing bulb will cause
overfeeding of the expansion valve.
Verify the expansion valve sensing bulb is positioned
and secured correctly.
Refrigeration System
7-21