Service manual

Refrigeration System Section 7
7-26 Part No. 80-1100-3
Q and J Model Dual 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 production
and ice formation pattern is normal and ice production is within 10% of charted capacity.
Ice Formation Pattern
Left side_____________
___________________
Right side ___________
___________________
Ice formation is
extremely thin on
outet of one side of
evaporator
-or-
No ice formation on
one side of
evaporator
Ice formation is
extremely thin on
outlet of one or both
sides of evaporator
-or-
No ice formation on
entire evaporator
Ice formation normal
-or-
Ice formation is
extremely thin on inlet
of one side 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 problems
and/or components not listed
on this table
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 a 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
_____ ______ ______
Beginning Middle End
If suction pressure is High or Low refer to a 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
Harvest Valve
Wait 5 minutes into the freeze
cycle.
Compare temperatures of
compressor discharge line
and both harvest valve inlets.
One harvest valve
inlet is Hot
-and-
approaches the
temperature of a Hot
compressor
discharge line.
Both harvest valve
inlets are
Cool enough
to hold hand on
-and-
the compressor
discharge line is Hot.
Both harvest valve
inlets are Cool
enough
to hold hand on
-and-
the compressor
discharge line is
Cool enough
to hold hand on.
Both harvest valve
inlets are 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