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 top
of one side of
evaporator
-or-
No ice formation on
one side of
evaporator
Ice formation is
extremely thin on top
of one or both sides of
evaporator
-or-
No ice formation on
entire evaporator
Ice formation normal
-or-
Ice formation is
extremely thin on
bottom 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
Hot Gas Valve
Wait 5 minutes into the freeze
cycle.
Compare temperatures of
compressor discharge line
and both hot gas valve inlets.
One hot gas valve
inlet is Hot
-and-
approaches the
temperature of a Hot
compressor
discharge line.
Both hot gas valve
inlets are
Cool enough
to hold hand on
-and-
the compressor
discharge line is Hot.
Both hot gas valve
inlets are Cool
enough
to hold hand on
-and-
the compressor
discharge line is
Cool enough
to hold hand on.
Both hot gas 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
Discharge line
temperature 160°F or
higher at the end of
the freeze cycle
Discharge line
temperature 160°F or
higher at the end of
the freeze cycle
Discharge line
temperature less
than 160°F at the end
of the freeze cycle
Discharge line
temperature 160°F or
higher at the end of
the freeze cycle
Final Analysis
Enter total number of boxes
checked in each column.
Hot Gas Valve
Leaking
Low On Charge
-Or-
TXV Starving
TXV Flooding Compressor