Service manual

Refrigeration System Section 7
7-22
Part No. 80-1206-3
Dual Expansion Valve - Q1400C/QDUALC
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 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 at the
outlet of one
evaporator
-or-
No ice formation on
top of one evaporator
Ice formation is
normal on both
evaporators
-or-
Ice formation is
extremely thin on
outlet of one or both
evaporators
or
No ice formation on
one or both
evaporators
Ice formation is
normal on both
evaporators
-or-
Ice formation is
extremely thin on inlet
of one evaporator
or
No ice formation on
one evaporator
Ice formation normal
-or-
No ice formation on
both evaporators
Safety limits
Refer to “Analyzing Safety
Limits” to eliminate all non-
refrigeration problems
Stops on safety limit:
1 or 2
Stops on safety limit:
1 or 2
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
_____ ______ ______
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
Normal or High
Suction pressure is
High
Cool Vapor Valve
Audible refrigerant flow
through left or right valve in
freeze cycle
No audible refrigerant flow
through left or right valve in
freeze cycle
No audible refrigerant flow
through left or right valve in
freeze cycle
No audible refrigerant flow
through left or right valve in
freeze cycle
Suction Line Temperature
Attach a temperature probe on
the suction line with-in 6” of the
shut-off valve outlet.
Record the low event at the
end of the freeze cycle.
Suction line temperature at
the suction shut-off valve is
greater than 10°F(-12.2°C)
at the end of the freeze
cycle.
Suction line temperature at
the suction shut-off valve is
greater than 10°F (-12.2°C)
at the end of the freeze
cycle
Suction line temperature at
the suction shut-off valve is
less than 10°F (-12.2°C)
at the end of the freeze
cycle
Suction line temperature at
the suction shut-off valve is
greater than 10°F (-12.2°C)
at the end of the freeze
cycle
Final Analysis
Enter total number of boxes
checked in each column.
Cool Vapor Valve Leaking Low On Charge
-Or-
TXV Starving
Refrigerant Overcharge
-Or-
TXV Flooding
Compressor