Sub Zero Ice Machine Does Not Operate – How to fix? by

How to Use the Troubleshooting Guide 3 The list below indicates how the Troubleshooting Guide is arranged. Identify the description of the problem that the unit is experiencing from the list and go to the page indicated. To the left of the problem description is a letter. Locate that letter in the left column of the Troubleshooting Guide. The center column will identify the possible causes for the problem. And, the information in the right column will explain what tests to perform in order to determine if what you are checking is the cause and/or what action to take to correct the problem.

Problem Posible Cause TEST / ACTION
Ice Machine Does Not Operate Improper Ambient Temperatures Ambient air temperature minimum = 50°F (10°C), maximum = 100°F (38°C) for models UC-15I and UC-15IP; 110°F (43°C) for models UC-15IO and UC-15IPO. Advise customer. NOTE: Check control board light to see if ice machine shutdown on over temperature limit (control board light will flash rapidly).
No Electrical Power to Appliance a. Verify fuse or circuit breaker is closed. Replace fuse; switch circuit breaker on. If circuit breaker trips or fuse blows again, check for electrical short at outlet or appliance. b. Verify ice machine is plugged into functioning, properly polarized and grounded 3- prong receptacle. Plug unit in; repair electrical outlet or power cord. c. See Wiring Diagrams and check for voltage at appropriate points from outlet to control board in control box. Reconnect, repair, replace wiring or connectors.
Control Board Fuse Open Visually inspect fuse, replace if open.
Transformer Fault If interior light functions or red control board light is energized, transformer is OK. If transformer is receiving power but no output, replace transformer.
Control Board Fault If transformer is supplying power to control board and red control board light will not energize, replace control board.
Control Panel (User Interface) Board Fault If red control board light is energized, but pressing “POWER” does not energize green “POWER” light, then check wiring between main control board and control panel board. If wiring is defective, replace wire harness; if wiring is good, replace control panel board.
Bin Thermostat Fault With no ice on bin level sensing tube, thermostat should be closed; open with ice on tube after ~ 3 minutes. Replace if defective.
Drain Pump Safety Switch is Open. (UC-15IP, UC-15IPO Only) Check drain hose for kinks or restrictions. Repair or replace bad hose.