Manitowoc STH042 4/16, Technician'S Handbook

Page: 88 / 146

88 Part Number STH042 4/16
Comparing Evaporator Inlet/Outlet
Temperatures
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°F (4°C) 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.
___________ ___________ ___________
Inlet
Temperature
Difference must be within
7°F (4°C) at 5 minutes into
the freeze cycle
Outlet
Temperature
5. Use this with other information gathered on the
Refrigeration System Operational Analysis Table to
determine the ice machine malfunction.