Comparing Evaporator Inlet/Outlet Temperatures - Manitowoc QM20 Technician's Handbook

COMPARING EVAPORATOR INLET/OUTLET
TEMPERATURES
Q130/Q170/Q210/Q270 Ice Machines Only
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.
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
5. Use this with other information gathered on the
Refrigeration System Operational Analysis Table
to determine the ice machine malfunction.
Part Number 80-01111-9 7/10
Important
___________
Difference must be
within 7°F (4°C) at
5 minutes into the
freeze cycle
___________
Outlet
Temperature
125