ICE MACHINES Q-Model Service Manual

Refrigeration System Section 7SINGLE EXPANSION VALVE ICE MACHINES -COMPARING EVAPORATOR INLET ANDOUTLET TEMPERATURESNOTE: This procedure will not work on the dualexpansion valve Q1300 Q1600 and Q1800 icemachines.The temperatures of the suction lines entering andleaving the evaporator alone cannot diagnose an icemachine. However, comparing these temperaturesduring the freeze cycle, along with using Manitowoc’sRefrigeration System Operational Analysis Table, canhelp diagnose an ice machine malfunction.The actual temperatures entering and leaving theevaporator vary by model, and change throughout thefreeze cycle. This makes documenting the “normal” inletand outlet temperature readings difficult. The key to thediagnosis lies in the difference between the twotemperatures five minutes into the freeze cycle. Thesetemperatures must be within 7° of each other.Use this procedure to document freeze cycle inlet andoutlet temperatures.1. Use a quality temperature meter, capable of takingtemperature readings on curved copper lines.2. Attach the temperature meter sensing device to thecopper lines entering and leaving the evaporator.ImportantDo not simply insert the sensing device under theinsulation. It must be attached to and reading theactual temperature of the copper line.3. Wait five minutes into the freeze cycle.4. Record the temperatures below and determine thedifference between them.5. Use this with other information gathered on theRefrigeration System Operational Analysis Table todetermine the ice machine malfunction.______________Inlet Temperature_______________DifferenceMust be within 7° at 5minutes into freeze cycle______________Outlet Temperature7-20 Part No. 80-1100-3