User manual SCOTSMAN CME1000A

[. . . ] CME855A & CME1000A INTRODUCTION This manual is intended as a reference for the installation of a Scotsman ice maker models CME855 and the CME1000. TABLE OF CONTENTS SPECIFICATIONS . page 15 SERVICE SPECIFICATIONS: CME855A SERVICE SPECIFICATIONS: CME1000A . page 26 A Service Parts List and the Wiring Diagrams are located in the center of this manual, printed on yellow paper. October, 1994 Page 1 CME855A & CME1000A SPECIFICATIONS Always refer to the nameplate, located on the back of the cabinet, for the: · model number, · serial number, · basic electrical requirements, · minimum circuit ampacity, · maximum fuse size, · and refrigerant charge. A serial number plate with the model number, serial number and refrigerant charge is located behind the front panel, near the control box. [. . . ] The refrigerant then flows into the suction line and back to the compressor. HARVEST CYCLE The only change between freeze and harvest is that a valve opens a path between the discharge line and the evaporator inlet. It allows hot discharge refrigerant gas to flow directly from the compressor to the evaporator inlet, warming the evaporators and causing the ice cubes to release. October, 1994 Page 13 CME855A & CME1000A WATER SYSTEM OPERATION Evaporators WATER SYSTEM SCHEMATIC Water Manifold and Distributors Drain Reservoir Inlet Water Valve Water Pump A fixed charge of water is brought into the reservoir during the harvest cycle. A water pump, running continuously, forces the water to the top of the evaporators, where it is distributed through manifolds, and then cascades down the evaporator surface by gravity. As it flows across the refrigerated evaporators, some of the water will be chilled enough to change form, turn to ice and stay frozen to the evaporator. Most of the water returns to the reservoir, to be sucked back into the pump and re-pumped over the evaporators. Water is forced over the evaporators during the freeze cycle to be changed into ice, and during the harvest cycle to assist the release of the ice. December, 1994 Page 14 CME855A & CME1000A COMPONENT DESCRIPTION Compressor Contactor The compressor contactor carries the compressor line current. The compressor contactor coil has power whenever the ice machine is making or harvesting ice. Cube Size Control This reverse acting (closes on temperature fall) thermostat determines how long the freezing cycle will be. The cube size control closes it's contacts when the evaporator & suction line cools to the set temperature. When the cube size control closes, it connects power to the timer motor. A variation in heat load (either ambient air or incoming water temperature) will affect the efficiency of the refrigeration system, and that will vary the length of time it takes the evaporators to cool to the temperature at which the cube size control is set to close, which, in turn, will affect the overall cycle time. Relay The multi-function, three pole, double throw, relay plugs into a socket on the printed circuit board in the control box. When the relay coil has power, the machine is in a freeze cycle, and when power is removed from the coil, the machine will be in the harvest cycle. The relay also by-passes the bin control during the harvest and freeze cycles, preventing the ice maker from shutting off in the middle of a cycle. The bypass action allows only complete freeze and harvest cycles; the only time that the ice maker can shut off on bin control is as the end of the harvest cycle. Timer - Timer & Switch Assembly The timer begins to turn when activated by the cube size control. The outer surface, or large diameter lobe of the timer cam, determines the length of time for finish freezing of the ice cubes, while the inner surface, or small diameter lobe, determines length of the harvest cycle. The single-pole, double throw microswitch on the timer controls the power to the plug in relay coil, making it either the freezing or harvest cycle. One complete rotation of the cam will take eight minutes. October, 1994 Page 15 Hot Gas Solenoid Valve The hot gas solenoid valve opens only during the harvest cycle. When it opens, it diverts the hot discharge gases so that they flow directly into the evaporator plates, by-passing the condenser and thermostatic expansion valve. The hot gases warm the evaporators, releasing the ice cubes from the ice cube molds. The hot gas solenoid valve is installed in a branch of the discharge line, and when the timer switches the ice machine into the harvest cycle, the energized solenoid coil lifts the valve stem within the valve body, allowing the hot discharge gas to be diverted to the evaporators. [. . . ] Access Valves: To use the access valves: a 3/16" allen wrench to check that the valve is CLOSED. · Close the valve and replace the caps when the job is finished. The valve must be closed and the caps must be on or the valve will leak. General Information: Work on the refrigeration system should only be done when it is certain that the system needs repair. VAPOR TEMP. [. . . ]