Manitowoc QD0202A, Service Manual

Page: 137 / 175

Section 7 Refrigeration System
Part No. 80-1100-3
7-25
REFRIGERATION SYSTEM OPERATIONAL ANALYSIS TABLES
Q, J and B Model Single Expansion Valve
This table must be used with charts, checklists and other references to eliminate
refrigeration components not listed on the table and external items and problems,
which can cause good refrigeration components to appear defective.
Operational Analysis 1 2 3 4
Ice Production Air-Temperature Entering Condenser_____________
Water Temperature Entering Ice Machine_________
Published 24 hour ice production________________
Calculated (actual) ice production_______________
NOTE: The ice machine is operating properly if the ice fill patterns is normal and ice production is within 10% of charted
capacity.
Installation and Water
System All installation and water related problems must be corrected before proceeding with chart.
Ice Formation Pattern Ice formation is extremely
thin on outlet of evaporator
-or-
No ice formation on the
entire evaporator
Ice formation is extremely
thin on outlet of evaporator
-or-
No ice formation on entire
evaporator
Ice formation normal
-or-
Ice formation is extremely
thin on inlet of evaporator
-or-
No ice formation on entire
evaporator
Ice formation normal
-or-
No ice formation on entire
evaporator
Safety Limits
Refer to “Analyzing Safety
Limits” to eliminate all non-
refrigeration problems.
Stops on safety limit:
1
Stops on safety limit:
1
Stops on safety limit:
1 or 2
Stops on safety limit:
1
Freeze Cycle
Discharge Pressure
_____ ______ ______
1 minute Middle End
into cycle
If discharge pressure is High or Low refer to freeze cycle high or low discharge pressure problem checklist to eliminate
problems and/or components not listed on this table before proceeding.
Freeze Cycle
Suction Pressure
_____ ______ ______
1 minute Middle End
If suction pressure is High or Low refer to freeze cycle high or low suction pressure problem checklist to eliminate problems
and/or components not listed on this table before proceeding.
Suction pressure is High Suction pressure is Low or
Normal
Suction pressure is High Suction pressure is High
Wait 5 minutes into the freeze
cycle.
Compare temperatures of
evaporator inlet and
evaporator outlet.
Inlet ____ ° F (° C)
Outlet ____ ° F (° C)
Difference ____ ° F (° C)
Inlet and outlet
within 7°
of each other
Inlet and outlet
not within 7°
of each other
-and-
Inlet is colder than outlet
Inlet and outlet
within 7°
of each other
-or-
Inlet and outlet
not within 7°
of each other
-and-
Inlet is warmer than outlet
Inlet and outlet
within 7°
of each other
Wait 5 minutes into the freeze
cycle.
Compare temperatures of
compressor discharge line
and harvest valve inlet.
The harvest valve inlet is
Hot
-and-
approaches the temperature
of a Hot compressor
discharge line.
The harvest valve inlet is
Cool enough to hold hand
on
-and-
the compressor discharge
line is Hot.
The harvest valve inlet is
Cool enough to hold hand
on
-and-
the compressor discharge
line is Cool
enough to hold hand on.
The harvest valve inlet is
Cool enough to hold hand
on
-and-
the compressor discharge
line is Hot.
Discharge Line Temperature
Record freeze cycle discharge
line temperature at the end of
the freeze cycle
_________ °F (°C)
Discharge line temperature
160°F (71.1°C)
or higher
at the end of the freeze
cycle
Discharge line temperature
160°F (71.1°C)
or higher
at the end of the freeze
cycle
Discharge line temperature
less than
160°F (71.1°C)
at the end of the freeze
cycle
Discharge line temperature
160°F (71.1°C)
or higher at the end of the
freeze cycle
Final Analysis
Enter total number of boxes
checked in each column.
Harvest Valve Leaking
Low On Charge
-Or-
TXV Starving
TXV Flooding Compressor