Manitowoc J-1300, Service Manual

Page: 123 / 165

Section 7 Refrigeration System
7-18
SINGLE EXPANSION VALVE ICE MACHINES
COMPARING EVAPORATOR
INLET AND OUTLET TEMPERATURES
NOTE: This procedure will not work on the dual
expansion valve J1300 and J1800 ice machines.
The temperatures of the suction lines entering and
leaving the evaporator alone cannot diagnose an ice
machine. However, comparing these temperatures
during the freeze cycle, along with using
Manitowoc’s Refrigeration System Operational
Analysis Table, can help diagnose an ice machine
malfunction.
The actual temperatures entering and leaving the
evaporator vary by model, and change throughout the
freeze cycle. This makes documenting the “normal”
inlet and outlet temperature readings difficult. The
key to the diagnosis lies in the difference between the
two temperatures five minutes into the freeze cycle.
These temperatures must be within 7
°
of each other.
Use this procedure to document freeze cycle inlet and
outlet temperatures.
1.
Use a quality temperature meter, capable of
taking temperature readings on curved copper
lines.
2. Attach the temperature meter sensing device to
the copper lines entering and leaving the
evaporator.
Important
Do not simply insert the sensing device under the
insulation. It must be attached to and reading the
actual temperature of the copper line.
3. Wait five minutes into the freeze cycle.
4. Record the temperatures below and determine the
difference between them.
5. Use this with other information gathered on the
Refrigeration System Operational Analysis Table
to determine the ice machine malfunction.
______________ ______________
Inlet Temperature Outlet Temperature
______________
Difference
Must be within 7
°°°°
5 min into freeze cycle