Service manual

ManualsBrandsScotsman ManualsIce MakerMDT6N90

INTRODUCTION

To the owner or user: The service manual you are

reading is intended to provide you, and the

maintenance or service technician with the

information needed to install, start up, clean,

maintain, and service this ice maker-dispenser.

The MDT6 is a combination nugget ice maker and

countertop dispenser. A water station is standard.

The ice making section is equipped with the

following features: electronic controls for bin level

and low water; thermostatic expansion valve; front

service for most components; and R-404A

refrigerant. The ice dispensing section is a

seamless plastic storage bin, with a stainless steel

ice agitator at the bottom to sweep the ice into the

dispensing chute.

MDT6N90

May 2001

Page 1

Table of Contents

FOR THE INSTALLER: Specifications ······························ Page 2

FOR THE INSTALLER ······································ Page 3

FOR THE PLUMBER ······································· Page 4

FOR THE ELECTRICIAN ····································· Page 5

FOR THE INSTALLER: Final Check List ····························· Page 6

INITIAL START UP ········································ Page 7

COMPONENT DESCRIPTION ·································· Page 8

COMPONENT DESCRIPTION ·································· Page 9

CONTROL BOX ········································· Page 10

ELECTRICAL SEQUENCE ···································· Page 11

OPERATION: Water ······································· Page 12

OPERATION: Refrigeration ···································· Page 13

OPERATION: Ice Vending ···································· Page 14

DISPENSE AREA SANITATION ································· Page 15

CLEANING and SANITIZING ··································· Page 16

SENSOR MAINTENANCE ···································· Page 17

BEARING MAINTENANCE ···································· Page 18

AUGER MAINTENANCE ····································· Page 19

SERVICE DIAGNOSIS ······································ Page 20

CONTROL SYSTEM DIAGNOSTICS ······························ Page 21

REMOVAL AND REPLACEMENT ································ Page 22

REMOVAL AND REPLACEMENT: Bearing And Breaker ···················· Page 23

REMOVAL AND REPLACEMENT ································ Page 24

REMOVAL AND REPLACEMENT: Water Seal ·························· Page 25

REMOVAL AND REPLACEMENT ································ Page 26

TO REMOVE AND REPAIR THE GEARMOTOR ASSEMBLY ·················· Page 27

REFRIGERATION SERVICE ··································· Page 28

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Keep it for future reference.

Note this symbol when it appears.

It marks a possible hazard.

Summary of content (28 pages)

PAGE 1
MDT6N90 INTRODUCTION To the owner or user: The service manual you are reading is intended to provide you, and the maintenance or service technician with the information needed to install, start up, clean, maintain, and service this ice maker-dispenser. The MDT6 is a combination nugget ice maker and countertop dispenser. A water station is standard.
PAGE 2
MDT6N90 FOR THE INSTALLER: Specifications This ice maker-dispenser is designed to be mounted on a machine stand, or a countertop. Before beginning the installation, check that all the materials and kits required are available at the installation location. Scotsman Ice Systems are designed and manufactured with the highest regard for safety and performance. They meet or exceed the standards of U.L., N.S.F., and C.U. L.
PAGE 3
MDT6N90 FOR THE INSTALLER Location This ice system is designed to be installed indoors, in a controlled environment. Minimum Maximum Air Temp 500F. 1000F. Water Temp 400F. 1000F. Water Pressure 20 psi 80 psi Voltage 104 126 Operating the machine outside of the above limitations, or outdoors, is potentially damaging to the machine; also it is misuse of the machine which may void the warranty. Service Limitations Do not install in a location where the top of the machine is within 6" of a fixed ceiling.
PAGE 4
MDT6N90 FOR THE PLUMBER CONFORM TO ALL APPLICABLE CODES Water Inlet Air Cooled Models: Connect a clean, potable and cold water supply to the 3 8” male flare at the back of the cabinet. Install a hand valve near the machine to control the water supply. Use 3 8” O.D. copper tubing. Water Treatment: In most areas, a water filter of some type will be useful.
PAGE 5
MDT6N90 FOR THE ELECTRICIAN CONFORM TO ALL APPLICABLE CODES Connect the electrical power supply for the unit to the wires in the junction box at the rear of the machine. Check the nameplate (located on the back panel) for the voltage requirements, and for the minimum circuit ampacity. The machine requires a solid chassis to earth ground wire. The ice maker should be connected to its own electrical circuit so it would be individually fused.
PAGE 6
MDT6N90 FOR THE INSTALLER: Final Check List 1. Is the icemaker-dispenser installed indoors, in a location where the air and water temperatures are controlled, and where they do not go beyond design limitations? ELECTRICAL? 2. is there an electrical service disconnect within sight of the installed machine? Is the machine on a separate circuit? Has the voltage been checked and compared to nameplate requirements? 3. Have all of the plumbing connections been made and checked for leaks? 4.
PAGE 7
MDT6N90 INITIAL START UP Pre Start Inspection 1. Remove the two front panels. 2. Check that all shipping blocks have been removed. 3. Remove any and all packing tape (check inside the storage bin). 4. Inspect the interior of the machine for loose screws or wires. Check that no refrigerant lines are rubbing each other. Check that the fan blade on air cooled models turns freely. 5. Check that the machine is installed correctly according to the final check list. Start Up 1.
PAGE 8
MDT6N90 COMPONENT DESCRIPTION RESERVOIR WATER LEVEL SENSOR ICE LEVEL SENSOR ICE STORAGE BIN CONTROL BOX EVAPORATOR DRAIN TUBE CONDENSER HI PRESSURE Ice Level Sensor: An electronic “eye”, it senses the presence of ice in the bottom of the ice CUT OUT discharge chute. Operates to turn the ice machine on and off automatically as the level of ice in the bin changes. Control Box: Contains the electrical controls that operate the machine.
PAGE 9
MDT6N90 COMPONENT DESCRIPTION Evaporator: A refrigerated vertical tube filled with water and containing a water seal and auger. Auger: A solid stainless steel double spiral auger, it pushes the ice crystals up to the top of the evaporator. Water Seal: A two part “face” seal, the top half rotating with the auger, the bottom half stationary, the sealing action being where the two seal “faces” meet. Ice Sweep: A plastic cap with “fingers”. It revolves with the auger to “sweep” the ice into the ice chute.
PAGE 10
MDT6N90 CONTROL BOX Circuit Board: The circuit board receives input signals from several sensors and translates them to control the electrical power supply to the various loads. The sensors include: · Touch Free ice or water. · Ice level in the bin. · Water level in the reservoir. The loads include: · Compressor contactor · Fan motor · Bin drive motor · Auger drive motor · Water solenoid.
PAGE 11
MDT6N90 ELECTRICAL SEQUENCE Refer the wiring diagram as needed. The “Power” light on the board glows whenever there is power to the machine (and the master switch is ON). If the machine is switched off at the master switch, but is otherwise ready to go, switching the master switch to ON does the following: · The bin empty and power lights on the circuit After a 6 minute delay, If the ice level sensor is clear (bin empty) for more than 15 seconds, the machine will start up again.
PAGE 12
MDT6N90 OPERATION: Water Water enters the machine through the 3/8" male flare at the rear of the cabinet, goes to the water reservoir which it enters through the float valve. The water then goes out the bottom of the reservoir tank to the bottom of the evaporator. Reservoir overflow, evaporator condensation and water in the sink are all routed to the drain.
PAGE 13
MDT6N90 OPERATION: Refrigeration Beginning at the compressor, the refrigerant is compressed into a high temperature gas. The discharge line directs this gas to the condenser. At the condenser (air or water cooled) the gas is cooled by either air or water and it then condenses into a liquid. This high pressure liquid then goes through the liquid line to the expansion valve.
PAGE 14
MDT6N90 OPERATION: Ice Vending When the ice dispensing sensor detects a container in front of it, the control board connects an electrical circuit to the ice chute door solenoid causing the ice chute door to open. At the same time power is connected to the agitator drive motor. Dispensing takes place when the agitator sweeps the ice through the ice dispensing chute: ice will continue to discharge out this chute as long as the agitator is turning. It stops when the agitator stops.
PAGE 15
DISPENSE AREA SANITATION The dispense area; spouts, sink, grill and splash panel will need periodic cleaning and maintenance. 1. The ice chute may be pulled down to remove it from the ice dispenser. Wash and sanitize it. 2. The sink grill may be removed for washing and sanitizing. 3. The sink should be flushed with hot water and wiped clean with sanitizer. 4. The splash panel requires special attention to clean it. · Push and release the Splash Panel Cleaning switch located to the left of the water spout.
PAGE 16
MDT6N90 CLEANING and SANITIZING It is the USER’S RESPONSIBILITY to see that the unit is properly maintained. It is always preferable, and less costly in the long run, to avoid possible down time by keeping it clean; adjusting it as needed; and by replacing worn parts before they can cause failure. The following is a list of recommended maintenance that will help keep the machine running with a minimum of problems. Cleaning should be scheduled at a minimum of twice per year.
PAGE 17
MDT6N90 SENSOR MAINTENANCE 1. The ice machine senses water level by a probe located in the water reservoir. At least twice a year, the probe should be removed from the reservoir, and the tip wiped clean of mineral build-up. 2. The bin control uses devices that sense light, therefore they must be kept clean enough so that they can “see”. At least twice a year, remove the bin control sensors from the ice chute, and wipe them clean.
PAGE 18
MDT6N90 BEARING MAINTENANCE The bearing in the breaker should also be checked at least two times per year. A. Check the bearing by: · unscrewing the breaker cover. Auger Stud · removing the ice chute cover Ice Sweep Cap Screw · unscrewing the auger stud · unscrewing the ice sweep · removing the water shed Breaker Cover Off Inspect the bearing. There should be plenty of grease in sight. If grease is needed the bearing and breaker should be removed to check the action of the bearing.
PAGE 19
MDT6N90 AUGER MAINTENANCE In some areas, the water supply to the ice maker will contain a high concentration of minerals, and that will result in an evaporator and auger becoming coated with these minerals, requiring a more frequent removal than twice per year. If in doubt about the condition of the evaporator and auger, the auger can be removed so the parts can be inspected. Note: Water filters can filter out suspended solids, but not dissolved solids. “Soft” water may not be the complete answer.
PAGE 20
MDT6N90 SERVICE DIAGNOSIS Symptom No ice is made, nothing operates No ice, auger motor is turning Unit makes ice, but very slowly. Possible Cause Unit off due to no power Unit off due to master switch in OFF position. Unit off due to low water level. Probable Correction Restore Power Switch master switch to ON. Check water supply, filter, float valve. Correct water supply. Check/clean ice level sensors. Unit off due to ice level sensors (photo-electric eyes) blocked.
PAGE 21
MDT6N90 CONTROL SYSTEM DIAGNOSTICS The control system consists of: · Control Board · Water Sensor · Ice Sensors · Vending Sensors 1, Power Light 2, Bin Empty Light 3, Delay Timer Light 4, No Water Light Explanation of Indicator Light On at all times when the master switch is ON and machine is connected to electrical power. On when ice level is low (unit making ice). Normal 6 minute off/delay start.
PAGE 22
MDT6N90 REMOVAL AND REPLACEMENT WATER RESERVOIR 1. Shut off the water supply to the icemaker. 2. Remove front panel and reservoir cover. 3. To remove float only, pry the mounting flanges apart enough to lift one float pivot pin out of the flange hole, and pull float up and out of the reservoir. 4. To remove reservoir, disconnect water inlet compression fitting at reservoir inlet. 5. Remove drain hose from reservoir. 6. Remove evaporator inlet hose from reservoir. 7. Remove water level sensor probe. 8.
PAGE 23
REMOVAL AND REPLACEMENT: Bearing And Breaker Note: Removal of the auger, water seal, evaporator and gearmotor must begin at the top of the assembly. To Remove the Breaker Bearing Assembly: Moving Parts Hazard. Disconnect electrical power to the icemaker dispenser before beginning. 1. Remove panels and disconnect electrical power. 2. Unscrew three studs and remove ice chute cover. 3. Unscrew and remove ice sweep. 4. Lift up and remove ice chute. 5.
PAGE 24
MDT6N90 REMOVAL AND REPLACEMENT To Remove the Auger: Turn off the water to the machine, and unclip the evaporator drain hose, pull it down and drain the evaporator into the bin or a container. e. If the auger is stuck use a slide hammer type puller to pull on the auger at the threaded hole. The size of that hole is 5/8"-18. Inspect the auger, the critical areas of the auger are: 1. The auger body. It should be clean and shining.
PAGE 25
REMOVAL AND REPLACEMENT: Water Seal To Remove the Water Seal: (Assuming all steps to remove the auger have been performed.) 1. The gearmotor/evaporator assembly will have to be exposed. (See illustration - next page) 2. Remove the 4 hex head cap screws holding the evaporator to the gearmotor assembly. Lift the evaporator up and off of the gearmotor. 3. Remove the snap ring or wire retainer from the grove under the water seal. 4. Pull or drive out the lower half of the water seal.
PAGE 26
MDT6N90 REMOVAL AND REPLACEMENT To Replace the Evaporator: (Assuming all the steps for removal of the thrust bearing, breaker, auger, and water seal have been performed.) 1. Recover the refrigerant from the ice maker. 2. Unsweat the refrigerant connections: a) At the thermostatic expansion valve outlet. Heat sink the TXV body when unsweating or resweating the adjacent tubing. b) At the suction line at the joint about 3" from the evaporator. 3. Remove the evaporator. 4.
PAGE 27
MDT6N90 TO REMOVE AND REPAIR THE GEARMOTOR ASSEMBLY (Assuming that the procedures through removal of the water seal have been performed.) 1. Remove the electrical wires from the gear drive motor. Electrical Shock Hazard. Disconnect electrical power to the icemaker dispenser before beginning. D) After replacing parts as required, (if any) reassemble the gearcase. The two smaller gears and the oil should be in the lower case, the output gear will be with the cover.
PAGE 28
MDT6N90 REFRIGERATION SERVICE General: This ice machine uses R-404A refrigerant and polyolester oil. Do NOT use mineral oil in this refrigeration system. Instructions for Liquid Charging R-404A In preparation for charging, the low side hose should have a sight glass, and/or a restricting device (such as a “Charge Faster”) installed in it for · When the system is serviced, a special liquid metering liquid into the low side of the system. line drier is required. It is included with 1.