Service Manual - MDT2C12

INTRODUCTION MDT2This manual provides the specifications and the NOTE: To retain the safety and performance builtstep-by-step procedures for the installation, into this ice machine, it is important that installationstart-up, operation, maintenance and cleaning for and maintenance be conducted in the mannerthe SCOTSMAN MDT2 counter top cubelet ice outlined in this manual.dispenser. Table of ContentsSPECIFICATIONS · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 2CABINET DIAGRAMS · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 3GENERAL INFORMATION AND INSTALLATION · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 4ELECTRICAL CONNECTIONS · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 5WATER SUPPLY AND DRAIN CONNECTIONS · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 6FINAL CHECK LIST · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 7OPERATING INSTRUCTIONS · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 8INITIAL START UP CONTINUED · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 9SETTING THE DISPENSING SELECTOR · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 11PRINCIPLE OF OPERATION · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 12REFRIGERANT CIRCUIT · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 13MECHANICAL SYSTEM · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 14COMPONENT DESCRIPTION · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 15COMPONENT DESCRIPTION · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 16COMPONENT DESCRIPTION · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 17COMPONENT DESCRIPTION · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 18SERVICE DIAGNOSIS · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 19SERVICE DIAGNOSIS · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 20MAINTENANCE AND CLEANING INSTRUCTION · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 21CLEANING INSTRUCTIONS OF WATER SYSTEM · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 22REMOVAL AND REPLACEMENT · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 23TOP BEARING REPLACEMENT · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 24BEARING REPLACEMENT - CONTINUED · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 25WATER SEAL · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Page 26 May 2002 Page 1

MDT2SPECIFICATIONSMDT2C12:Ice Maker Dispenser TouchFree 200 lb ice making capacity Cublet 12 lb storageImportant operating requirements:- Air temperature MIN MAX 50°F 100°F- Water temperature 40°F 95°F 20 psi 70 psi- Water pressure -10% +10%- Electrical voltage variations fromvoltage rating specified onnameplateTo keep your SCOTSMAN CUBELET DISPENSERat peak performance levels, periodic maintenancechecks must be carried out as indicated in thismanual.MACHINE SPECIFICATIONSModel Cond. Cabinet Size Finish Comp. Ice binMDT2C12-1A unit S. Steel HP cap Air 34 13/32” high x 15 9/32” wide x 26 7/64” deep 3/8 12 lb.Basic Amps Watts Amps fuseelectrical 6 550 15115/60/1Unit is equipped with leveling legs.The unit has a power cord. May 2002 Page 2

MDT2CABINET DIAGRAMS May 2002 Page 3

MDT2GENERAL INFORMATION AND INSTALLATIONUNPACKING AND INSPECTION LOCATION AND LEVELING1. Call your authorized SCOTSMAN Distributor or WARNING: This Ice Dispenser is designed forDealer for proper installation. indoor installation only. If the machine is operated for extended periods at temperatures exceeding2. Visually inspect the exterior of the packing and the following limitations it will constitute misuseskid. Any severe damage noted should be reported under the terms of the SCOTSMAN Manufacturer’sto the delivering carrier and a concealed damage Limited Warranty resulting in LOSS of warrantyclaim form filled in subject to inspection of the coverage.contents with the carrier’s representative present. Position the unit in the selected permanent3. a) Cut and remove the plastic strip securing the location. Criteria for selection of location include:carton box to the skid. Min Maxb) Cut open the top of the carton and remove the 100°Fpolystyrene protection sheet. Air Temperature 50°F 95°F 70 psic) Pull out the polystyrene posts from the corners Water Temperature 40°F +10%and then remove the carton. Water pressure 20 psi4. Remove the top and sides panels of the unit andinspect for any concealed damage. Notify carrier of Voltage -10%your claim for the concealed damage as stated instep 2 above. (Compared to the nameplate)5. Remove all internal support packing and Service access: adequate space must be left for allmasking tape. service connections through the rear of the ice machine.6. Check that refrigerant lines do not rub against ortouch other lines or surfaces, and that the fan This machine is air-cooled and sucks air throughblades move freely. the left side panel and blows air out the rear side of the top panel. Do not install the machine where the7. Check that the compressor fits snugly onto all its left and upper rear side airflows might be blocked.mounting pads. A minimum clearance of 6 inches is required at the8. Use clean damp cloth to wipe the surfaces left and upper rear side for air circulation.outside of the cabinet. It is important that the machine be installed in a9. See data plate on the rear side of the unit and location where it has enough space around it to becheck that local main voltage corresponds with the accessible for service. Avoid hot, dirty andvoltage specified on it. crowded locations.CAUTION: Incorrect voltage supplied to the ice NOTE: Do NOT place anything on top of themachine will void your parts replacement program. machine. Leave the upper louvers open for proper air exhaust.10. Remove the manufacturer’s registration card The base of the MDT2 must be sealed to thefrom the inside of the Users Manual and fill-in all counter top.parts including Model and Serial Number takenfrom the data plate. Forward the completed 1. Place the unit in its final position.self-addressed registration card to SCOTSMANfactory. 2. Place a bead of sealant on the counter top to match the outside edge of the cabinet base and sink. Food grade silastic sealant such as Scotsman part number 19-0529-01 is recommended. May 2002 Page 4

MDT2ELECTRICAL CONNECTIONSSee data plate for current requirements todetermine wire size to be used for electricalconnections. All SCOTSMAN ice machines requirea solid earth wire. This SCOTSMAN ice machine issupplied from the factory completely pre-wired andonly needs to be plugged into a nearby 115 voltoutlet.Make sure that the ice machine is connected to itsown circuit and individually fused (see data platefor fuse size).The maximum allowable voltage variation shouldnot exceed -10% and +10% of the data platerating. Low voltage can cause faulty functioningand may be responsible for serious damage to theoverload switch and motor windings.NOTE: All external wiring should conform tonational, state and local standards and regulations.Check voltage on the line and the ice machine’sdata plate before connecting the unit.May 2002 Page 5

MDT2WATER SUPPLY AND DRAIN CONNECTIONSGENERAL WATER DRAINWhen choosing the water supply for the ice flaker, The recommended drain tube is a copper, rigidconsideration should be given to: plastic or reinforced flexible tubing (supplied) with .75\" (19mm) I.D. which runs to an open trappeda) Length of run and vented drain. When the drain is a long run, allow1/4\" drop per foot.b) Water clarity and purity Note: Although soft, easily kinked vinyl tubing isc) Adequate water supply pressure not recommended for a drain, a short length of ¾” ID vinyl tubing is required to connect a rigid drainWater is the most important single ingredient in tube to the 20 mm (25/32”) fitting on the back ofproducing ice - these three items are very the MDT2.important.Low water pressure, below 20 psi may causemalfunction of the ice machine unit.Water containing excessive minerals will tend to Install a vertical open vent on the drain line highproduce scale build-up on the interior parts of the point at the drain connection to ensure goodwater system while water that’s too soft (water draining.contains too few mineral salts), will produce a veryhard flaked ice. The ideal drain receptacle is a trapped and vented floor drain.PLUMBING CONNECTIONS MUST CONFORMTO ALL APPLICABLE CODES NOTE: The water supply and the water drain must be installed to conform with the localCONNECT TO POTABLE WATER ONLY code. In some case a licensed plumber and/or a plumbing permit is required.The model MDT2 is capable of having waterconnections through the bottom base or throughthe rear bottom side of the machine. In this secondcase it is necessary to remove the small panel atthe bottom rear.WATER SUPPLYConnect to the 3/4\" male water inlet fitting, usingthe supplied fitting, to the cold water supply line. Ashut-off valve should be installed in an accessibleposition between the water supply line and the unit.If the water contains a high level of impurities,consider installing a water filter or conditioner. May 2002 Page 6

MDT2FINAL CHECK LIST1. Is the unit in a room where the ambienttemperatures are within a minimum of 50°F even inwinter months?2. Is there at least a 6\" clearance around the unitfor proper air circulation?3. Is the unit level?4. Have all the electrical and plumbing connectionsbeen made, and is the water supply shut-off valveopen?5. Has the voltage been tested and checkedagainst the data plate rating?6. Has the water supply pressure been checked toensure a flowing water pressure of at least 20 psi.7. Check all refrigerant lines and conduit lines toguard against vibrations and possible failure.8. Has the unit been sealed to the counter top?9. Has the owner/user been given the UsersManual and been instructed on the importance ofperiodic maintenance checks?10. Has the Manufacturer’s registration card beenfilled in properly? Check the model and serialnumber against the serial plate and mail theregistration card to Scotsman.11. Has the owner been given the name and thephone number of the authorized SCOTSMANService Agency serving them?May 2002 Page 7

MDT2OPERATING INSTRUCTIONS B. After 3 minutes have elapsed – the stand by period – the unit starts operating by activatingINITIAL START UP systems in following sequence:After having correctly installed the ice machine and 1. GEAR MOTORcompleted the plumbing and electrical connections,perform the following “Start-up” procedure. 2. COMPRESSORRemove the control board inspection panel and 3. FAN MOTOR – which is controlled by thecover to view the lights on the control board. condenser temperature sensor. The probe is within the condenser fins.A. Open the water supply line shutoff valve and 4. 2nd RED LED switches off (Fig. 2).turn the main switch on the power supply line tothe ON position. C. Two or three minutes after compressor start up; cubelet ice should begin dropping off the ice spoutThe GREEN LED will glow to signal that unit is into the storage bin.under power.NOTE: Every time the unit is turned on after beingshut off for a period of time (electricallydisconnected) the 2nd RED LED will blink for 3minutes (Fig.1). Fig 1 Reset buttonBLINKING – 3 MIN.STAND-BY PERIOD Bin empty Bin full Hi cond temp when Steady No water 3 minute wait when Blinking Power Auger Motor when Steady Reset button Hi evap temp when Blinking Fig 2 Bin empty Bin full No water Hi cond temp when Steady Power 3 minute wait when Blinking Auger Motor when Steady Hi evap temp when Blinking May 2003 Page 8

INITIAL START UP CONTINUED MDT2NOTE: If the evaporating temperature has not OPERATION CHECKS UPON THE UNIT STARTdropped lower than 30° F within ten minutes of UPcompressor start-up, the evaporating temperature D. Remove the service panels and (if needed)sensor will detect the abnormal temperature and connect the refrigerant service gauges to thestop the unit operation. corresponding service valves to check both the HI and LO refrigerant pressures.In this circumstance, the 3rd warning YELLOWLED will blink (Fig.3). NOTE:The condenser temperature sensor, which is located within the condenser fins, keeps theAfter diagnosing and eliminating the cause of the head (condensing) pressure between two presetpoor evaporating temperature (insufficient valves.refrigerant in the system, inoperative compressoror inoperative evaporator sensor), push the If proper flow of cooling are is prevented by aRESET BUTTON on the control board. clogged condenser or inoperative fan motor, the condenser temperature rises. When it reachesBefore resuming operation the unit will go through 158° F the condenser temperature sensorthe usual 3 minute STAND-BY period. shuts-off the ice machine and turns on the 2nd RED WARNING LIGHT (Fig.4).Fig 3 Reset button Bin empty Bin full Hi cond temp when Steady No water3 minute wait when Blinking Power Auger Motor when Steady Reset button Hi evap temp when Blinking Fig 4 Bin empty Bin full No water Hi cond temp when Steady Power3 minute wait when Blinking Auger Motor when Steady Hi evap temp when Blinking May 2003 Page 9

MDT2 signaling that there is a full storage bin (Fig.6).After diagnosing and fixing the cause of the Remove your hand to allow the electronic eye totemperature rise, push the RESET BUTTON on resume normal operation. After about 6 secondsthe control board. the flaker will resume the ice making process and the YELLOW LED will turn off – after the 3 minuteBefore resuming operation the unit will go through STAND-BY period.the usual 3 minute STAND-BY period. NOTE: The ICE LEVEL CONTROL (INFRAREDE. Check for the correct CUT-OUT and CUT-IN of SYSTEM) is independent of the temperature.the float reservoir water level sensors by shutting However, the reliability of its detection can beoff the valve on the water supply line. This will affected by dirt and scale sediment that maycause a gradual decrease of the water level in the deposit directly on the light source and on thefloat reservoir and as soon as the level gets below receiver.the sensors, the flaker stops operating and the 5thYELLOW WARNING LED will glow to signal the To prevent ice machine malfunction due toshortage of water (Fig.5). sediment build-up, be sure to follow the instructions for the periodic cleaning of the lightNOTE: The water level sensor detects the sensor elements as detailed in thepresence of sufficient water in the float reservoir MAINTENANCE AND CLEANINGand confirms it to the microprocessor by INSTRUCTIONS section of this manual.maintaining a low voltage current flow between thetwo sensors using the water as conductor.CAUTION: The use of Fig 5 Reset buttonde-mineralized water (waterwith no salt content) having an Bin empty Bin fullelectrical conductivity lower than Hi cond temp when Steady No water30mS, will cause the water 3 minute wait when Blinking Powersensors to stop workingproperly which will CUT-OUT Auger Motor when Steady Reset buttonthe flaker operations and turn on Hi evap temp when Blinkingthe YELLOW LED that indicates Bin fulla shortage of water, even though Fig 6 No waterwater is indeed in the reservoir. Power Bin emptyAfter this is done, open the water Hi cond temp when Steadysupply line shutoff valve to refill 3 minute wait when Blinkingthe float reservoir; the 5thYELLOW LED goes off and the Auger Motor when Steady2nd RED LED starts blinking. Hi evap temp when BlinkingThe gear motor will start-upimmediately, 2 seconds later thecompressor will start and afterthe 3 minutes the unit resumesnormal operation.F. To check for the correctoperation of the electronic eyethat controls ice bin level, placeone hand between the sensing“eye” (located in the ice spout) tointerrupt the light beam. Thisinterruption will cause the 1stRED LED to go out. After about6 seconds the unit shuts off andthe 6th YELLOW LED will light May 2003 Page 10

MDT2SETTING THE DISPENSING SELECTORSetting the dispensing time a) First, select the Dispensing Mode by pushing the proper switch.It’s possible to modify the dispensing time to 5, 10or 15 seconds. To modify the original setting time b) Place a glass or a carafe in front of the two(5 seconds): Optical Dispensing Devices.a) Push and hold the 4th switch (CONTINUOUS)for 10 seconds until the first 3 lights start to blink, c) The dispensing drive motor and/or the waterb) Push & release the 1st switch (ICE) for a 5 solenoid valve starts. Ice and/or water issecond dispense. discharged through the bottom plastic spout.c) Push & release the 2nd switch (ICE ANDWATER) for a 10 second dispense. The drive motor and/or the water solenoid valved) Push & release the 3rd switch (WATER) for a 15 remains in operation (per dispensing time settings)second dispense. unless the glass or carafe is removed.The unit resumes a default dispense setting (Ice, Push the CONTINUOUS switch and check againIce and Water or Water) after each dispense. for the dispensing mechanism operation per the steps above.To modify the resume mode (from factory set toICE) push the desired switch (ICE, ICE AND The drive motor and/or the water solenoid valveWATER or WATER ) for 5 seconds. will remain in operation until the glass or carafe is removed.H. CHECK OF THE DISPENSING OPERATINGMECHANISM I. If connected, remove the refrigerant service gauges and re-attach the service panels.To check for the correct operation of the dispensingmechanism: J. Instruct the owner/user on the general operation of the ice machine and its required cleaning and care.May 2002 Page 11

MDT2 In the freezer the incoming water gets chilled into soft (slush) ice, which is moved upward by thePRINCIPLE OF OPERATION rotating action of the auger. The stainless steel auger rotates counter-clockwise within the freezerWATER CIRCUIT and is powered by a direct drive gear motor. It carries the ice upward along the inner walls of theThe water enters the machine through the water freezer and as it raises the ice gets progressivelyinlet fitting (which has a strainer and is located at thicker and harder. As the ice rises upward itthe rear side of the cabinet) and goes to the water moves toward the icebreaker (which is located onreservoir through a float valve. the top end of the auger), where it gets compacted, cracked and shifted horizontally to be dischargedNOTE: The presence of the water in the float out through the ice spout, into the storage bin.reservoir is detected by a system of two sensorsthat operate in conjunction with the PC Board. The Once the ice machine is turned on it starts thetwo sensors use the water as a conductor to automatic ice making process, which will continuemaintain a low voltage current flow between them. until ice storage bin is full enough to trigger theIf the water used is very soft (de-mineralized) or control “eye” located on the sides of the ice spout.the float reservoir is empty, the current that flows As the ice level raises it interrupts the light beambetween the sensors may become weak or cease. running between the two infrared lamps. The unitIf this happens, the PC Board will shut off the stops after six seconds and the YELLOW LEDflaker’s operation and the YELLOW LED will light turns on to signal that there is a “Full Storage Bin”.signaling a “Shortage of water.” NOTE: The interruption of the light beam betweenThe float reservoir is positioned at the side of the the two light sensors is signaled by the 1st REDfreezing cylinder high enough to maintain a LED located on the front of the PC Board turningconstant water level around the freezer auger. In off.fact, the water flows from the reservoir into thebottom inlet of the freezing cylinder to surround the After about 6 seconds of steadystainless steel auger, which is vertically fitted in the interruption of the light beam the unitcenter of the freezer. stops and the “Full Storage Bin” YELLOW LED glows. The six second delay prevents the unit from stopping for small interruptions in the light beam such as is caused by flakes sliding along the ice spout before dropping into the bin. As ice gets scooped out of the storage bin, the light beam between the two sensors resumes. The 1st RED LED lights up; 6 seconds later the ice machine resumes making ice and the YELLOW LED goes off.May 2002 Page 12

REFRIGERANT CIRCUIT MDT2The hot gas refrigerant discharged from the When the condenser temperature goes below thecompressor reaches the condenser where it is pre-fixed limit, the temperature sensor changes itscooled down and condenses into liquid. electrical resistance again by reducing the flow of current to the PC Board to cause a temporary stopFlowing into the liquid line it passes through the of the Fan Motor.drier filter, then it goes all the way through thecapillary tube where it loses some of its pressure. NOTE: If the condenser temperature probe sensesAt this time the pressure and temperature are a rise in temperature to 158°F for one of thelowered and the refrigerant enters into the following abnormal reasons:evaporator coil wrapped around the freezer innertube. · CLOGGED CONDENSERThe water being constantly fed into the freezer · FAN MOTOR OUT OF OPERATIONinner tube exchanges heat with the refrigerant · AMBIENT TEMPERATURE HIGHER THANcirculating in the evaporator coil. This causes therefrigerant to boil-off and it evaporates, thereby 109.4°Fchanging from liquid into vapor. It will cause the total and immediate SHUT-OFF ofThe vapor refrigerant then passes through the the machine in order to prevent the unit fromsuction accumulator and the suction line where the operating in abnormal and dangerous conditions.refrigerant exchanges heat with the one flowing When the probe stops the ice machine the 2nd REDinto the capillary tube (warmer) before being LED will turn on, warning the user of the Hisucked into the compressor to be re-circulated. Temperature situation. After eliminating the causeThe refrigerant heat pressure is kept between two of the increase in temperature, push the RESETpre-set values 131¸145 psig by the condenser button (PC Board) to restart the ice machine. Thetemperature sensor (the probe is located within the 2nd RED LED starts blinking and three minutescondenser fins) in air-cooled versions. later the flaker unit resumes normal operation.When this condenser temperature sensor detects arise in condenser temperature (beyond the The refrigerant suction or Lo-pressure will be (inpre-fixed limit) it changes its electrical resistance normal ambient conditions about 70°F) about 14.5and sends a low voltage power flow to the PSIG within a few minutes from the unit’s start-up.microprocessor on the PC Board that energizes This value can vary by 1.5 to 2.9 psig in relation to(through a TRIAC) the Fan Motor in ON-OFF the water temperature variations influencing themode. freezer cylinder. NOTE: If no ice is made within ten minutes of unit start up and the evaporating temperature detected by the evaporator sensor is higher than 30° F the ice machine stops and the 3rd WARNING YELLOW LED blinks.May 2002 Page 13

MDT2MECHANICAL SYSTEM for the wrong rotation) and the 3rd YELLOW WARNING LED turns on. This is done to avoidThe mechanical system of the SCOTSMAN overloading the electrical and mechanicalNugget Ice Dispenser consists of a gear motor components of the entire Drive System and extendassembly that drives (through a ratchet coupling) a their durability.worn shaft or auger placed on its vertical axiswithin the freezing cylinder. NOTE: After diagnosing and eliminating the source of the gear motor slow rotation, restart the unit byThe gear motor is made of a single-phase electric pushing the RESET button to or turning the powermotor with a permanent capacitor. This motor is line main switch OFF and ON.directly fitted in the gear case through which itdrives – in a counter clockwise rotation at a speed NOTE: Any time the machine stops with a problemof 9.5 rpm – the freezer auger linked to it by the the front 4 LED’s start to blink.ratchet coupling. REFRIGERANT METERING DEVICE:NOTE If the gear motor rotates in the wrongdirection (counter-clockwise) or is not rotating at all ·Capillary tubethe unit will stop immediately and the 3RDWARNING YELLOW LED will turn on showing the OPERATING PRESSURESintervention of the Electromagnetic Safety Device -based on Hall Effect principle. (With 70°F ambient temperature)After diagnosing and eliminating the source of the ·Discharge pressure: 130 to 145 psigfailure, restart the unit by pressing the RESET ·Suction pressure: 14.5 psigbutton or turn the power switch OFF and ON (Fig. ·REFRIGERANT CHARGE (R 134 A): 13 oz.7). NOTE: Before charging the refrigerant systemThe RED LED will start blinking and after 3 always check the type of refrigerant and quantityminutes the ice machine will resume normal as specified on the individual ice machine dataoperations by running first the gear motor and then plate.the compressor. The refrigerant charges indicated are relatives toWhen the gear motor rotating speed is slowed averages operating conditions.below 1300 rpm - normal speed is 1400 rpm - theElectromagnetic Safety Device transmits anelectrical signal to the MICROPROCESSOR tostop the unit operation immediately (just as it does Fig 7 Reset button Bin empty Bin full Hi cond temp when Steady No water 3 minute wait when Blinking Power Auger Motor when Steady Hi evap temp when Blinking May 2003 Page 14

COMPONENT DESCRIPTION MDT2A. EVAPORATOR TEMPERATURE SENSOR - If the temperature rises to 158°F or above theBLUE 2 POLE CONNECTOR - MANUAL RESET current sent to the microprocessor causes the machine to cease operation and turns on the 2ndThe evaporator sensor probe is inserted into its RED WARNING LED.tube well, which is welded on the evaporator outletline. It detects the temperature of the refrigerant on NOTE: After fixing the problem that caused thethe way out of the evaporator and signals it by high condenser temperature, press the RESETsupplying a low voltage current flow to the PC button or turn the power line main disconnectBoard microprocessor. According to the current switch OFF and ON to restart the unit after the shutreceived, the microprocessor lets the ice machine down.to continue its operations or not. If within 10minutes of startup the evaporating temperature The fan motor will cycle on an off to maintain thedoes not go below 30°F the evaporator sensor discharge pressure.signals the microprocessor to stop the unitoperation immediately and causes the 3rd D. GEAR MOTOR ROTATION AND SPEEDWARNING YELLOW LED to blink. SENSOR - RED FOUR POLE CONNECTOR - MANUAL RESETB. WATER LEVEL SENSOR - RED TWO POLECONNECTOR – AUTOMATIC RESET This safety device is housed on top of the Drive Motor and detects - based on the Hall EffectThis sensor system consists of two small stainless principle - the rotating speed and rotating directionsteel rods vertically fitted on the inner face of the of the drive Motor. Should the rotating speed dropreservoir cover and electrically connected to the below 1300 rpm the magnitude measured by thislow voltage circuit of the PC Board. When the device signals the microprocessor to stop the unitcover of the reservoir is positioned properly the tips and turns on the 3rd YELLOW LED. The sameof both rods dip into the reservoir water and signal reaction occurs when the drive motor rotates in theits presence by supplying power to the PC Board. wrong direction (counterclockwise) or it doesn’t rotate at all.NOTE: In the event of shortage of water in thereservoir or if the water used is too soft NOTE: After diagnosing and eliminating the(de-mineralized) to cause greater resistance to the problem that caused the intervention of the safetycurrent flow (conductivity lower than 30mS) this device, press the RESET button or turn the powersensor system causes the machine to shutoff to line main disconnect switch OFF and ON to restartprotect it from running with an interrupted or the unit after the shut down.inadequate water supply.When this happens the 5th YELLOW LED will turnon warn that the ice machine is off and why.C. CONDENSER TEMPERATURE SENSOR -BLACK TWO POLE CONNECTOR –MANUALRESETThe condenser temperature sensor probe (locatedwithin the condenser fins) detects condensertemperature variations and signals them bysupplying current, at low voltage, to the PCBOARD.Current to the microprocessor on the PC Boardvaries and as it does the microprocessor supplies,through a TRIAC, power at a high voltage to thefan motor so that it can cool the condenser andreduce its temperature.May 2002 Page 15

MDT2COMPONENT DESCRIPTION F. ICE/WATER OPTICAL DISPENSING DEVICE - BLUE FOUR-POLE CONNECTORE. ICE BIN LEVEL LIGHT CONTROL – BLACKFOUR POLE CONNECTOR –AUTOMATIC Located on the front of the dispensing area itRESET consists of a combination of an infrared Transmitter and Receiver.The electronic ice bin level control (located on theice spout) stops the operation of the ice machine When a glass or a carafe is placed in front of thewhen the light beam between the light source and Infrared sources, the optical device transmits athe sensor gets interrupted by the ice which signal to the PC Board. This activates theaccumulates in the spout. dispensing drive motor, which in turn, puts into rotation a dispensing vane that pushes the iceWhen the light beam is interrupted for 6 seconds, towards a rectangular opening located in thethe 1st RED LED (on the front of the PC board) bottom of the storage bin.goes off and the ice machine stops ice productionand turns on the 6th YELLOW LED to show that After the glass/carafe is removed or the dispensingthere is a full storage bin. time has elapsed (5, 10 or 15 seconds according to the setting) the infrared transmitter switches off theThe 6-second delay prevents interruption of dispensing drive motor.machine operation in the case of minimal breaks inthe light beam that can occur due to the icedropping through the ice spout blocking the sensor.As soon as ice is scooped out of the bin, the lightbeam resumes contact with the two infraredsensors of ice level control. The RED LED lightsup and after 6 seconds the ice machine resume itsoperation and the 6th YELLOW LED turns off.Fig 6 Reset button Bin empty Bin full Hi cond temp when Steady No water3 minute wait when Blinking Power Auger Motor when Steady Hi evap temp when Blinking May 2002 Page 16

COMPONENT DESCRIPTION MDT2G. FRONT DISPENSING SELECTOR/DISPLAY - The PC BOARD is the brain of the system. ItBLACK SIX-POLE CONNECTOR relays through its microprocessor, the signals received from the sensors to control the operationPlaced in the upper front part of the dispensing of the different electrical components of the icearea it is used to select (varies by machine model): machine (compressor, gear motor, etc.) as well as the dispensing of the ice and water.a) Ice (first switch) The six LEDS on the front of the PC BOARD indicate the following:or RED LIGHT - Empty storage bina) Ice (first switch) RED LIGHTb) Ice and water (second switch) ON all the time - Unit shut-off due to a Too high-condensingc) Water - not chilled - (third switch) temperature > 158°F BlinkingIt is also possible to set up for “continuous” - 3 minutes start up delay timedispensing operation just by pushing the fourthswitch before or after the selection of the YELLOW LIGHTdispensed product. ON all the time - Unit shut-off due to the wrong rotation direction ofOnce completed the dispensing selector/display gear motorresumes its original dispensing setting mode. - Unit shut-off due to the too lo speed of gear motor BlinkingNOTE: It is possible to modify the original resume - Unit shut-off due to a Too high-evaporating temp.mode (default) by pushing the corresponding >-30°F after 10 min of operationswitch for 5 seconds (all machines are factory setto the ICE dispensing mode). GREEN LIGHT - Unit under electrical powerIt is also possible to modify the dispensing timecontrolled by the PC Board to 5, 10 or 15 seconds YELLOW LIGHTby: - Unit shut-off due to a too lo-water level into float tank a) Push and hold the 4th switch “continuous” forapproximately 10 seconds till the first 3 lights start YELLOW LIGHTto blink - Unit shut-off at full storage bin b) Pushing the 1st switch (ICE) is equivalent to 5 BLINKING – 3 MINUTE STAND-BY PERIODseconds. Pushing the 2nd switch (ICE+WATER) isequivalent to 10 seconds. Pushing the 3rd switch (WATER) is equivalent to15 seconds.H. PC BOARD (Data processor)The PC BOARD (in a plastic box on the right sideof the unit) consists of two separated printed circuitboards; one at high voltage and the other at lowvoltage, protected by three fuses, integrated with aRESET button. It also consists of six aligned LEDSmonitoring machine operation, input terminals forthe leads of the sensor probes as well as input andoutput terminals for the leads of the ice machineelectrical wires.May 2002 Page 17

MDT2COMPONENT DESCRIPTION The drive motor rotor is kept aligned on its vertical axis by two permanently lubricated ball bearings.I. FLOAT RESERVOIR The gear case contains a train of three spur gears, the first of which is fiber to limit the noise level. AllThe float reservoir consists of a plastic water pan three gears are encased in case bearings and arewhich has a float valve with a set screw on it. The covered by lubricant grease (MOBILPLEX IP 44).float valve modulates the incoming water flow tomaintain a constant water level in the reservoir that Two seal rings, one fitted on the rotor shaft and thecorresponds to the one in the freezing cylinder to other on the output shaft, keep the gear caseensure proper ice formation and fluidity. sealed. However, the interior can be inspected and serviced by unbolting the two halves of theOn the inside of the reservoir cover are two water aluminum gear case housing.level sensors that detect the presence or shortageof water in the reservoir. The gear reducer output shaft is connected to the freezer auger by a ratchet coupling which is madeNOTE: It is very important to make sure that the of two toothed halves that engage only if turned incover on the reservoir is seated properly to enable the correct direction (counter-clockwise).the sensors to efficiently control the water level toavoid undue shutoff. M. FAN MOTOR (Air cooled version)J. FREEZING CYLINDER (EVAPORATOR) The fan motor is controlled through the PC Board and the TRIAC by the condenser temperatureThe freezing cylinder is made of a stainless steel sensor. Normally it operates to draw cooling airvertical tube. The cooling coil is wrapped around through the condenser fins.its exterior with the evaporating chamber. In itsinterior is the auger which rotates on a vertical axis In a cold ambient situation, the fan motor can runthat is kept aligned by the top and bottom bearings. intermittently as the condenser pressure must beA water seal system is located in the bottom part of kept between two corresponding head pressurethe freezer and the ice breaker is fitted on top end. values.The water constantly flows into the cylinder bottom N. ICE DISPENSER DRIVE MOTORand it freezes into ice when it comes into contactwith the cylinder inner walls. The ice is then lifted Located on the upper side of the storage bin, itup by the rotating auger, compacted and forced out turns the dispensing vane by a milled shaft insideby the icebreaker. the round storage bin.K. ICE BREAKER By rotating, the dispensing vane pushes the ice towards the bottom rectangular opening to forceThe icebreaker is made up of several rectangular the nugget ice to go through the bottom outletopenings that the ice is forced to pass through. By spout.undergoing this process, the ice loses its excess ofwater content and drops into the bin in hard dry O. STORAGE BINbits of ice. The storage bin is located in the front of the iceThe icebreaker houses the top bearing, which is machine. It main purpose is to store the cubeletmade of two roller bearings, positioned to ice produced by the evaporator until it reaches itswithstand the auger axial and radial loads. This maximum level. In its bottom is placed the icebearing is lubricated with a food-grade, spout as well as the water drain hole.water-resistant grease. Inside the ice spout opening is the water outletNOTE: Check the conditions of both the lubricant tube connected to the solenoid valve.grease and the bearings every six months. P. DISPENSING WATER SOLENOID VALVEL. DRIVE GEAR MOTOR Energized and controlled by the PC Board, itThis motor reducer is made of a single-phase allows a metered quantity of not chilled water to beelectric motor with a permanent capacitor directly dispensed through the same opening of the ice.fitted on a gearbox. May 2002 Page 18

MDT2SERVICE DIAGNOSISSYMPTOM POSSIBLE CAUSE SUGGESTED CORRECTIONUnit will not run Blown fuse in P.C. Board Replace fuse & check for cause of blown fuseNo LED lights Master switch in OFF position Turn switch to ON position Inoperative P.C. Board Replace P.C. Board6th Yellow LED glows Loose electrical connections Check wiring5th Yellow LED glows Inoperative or dirty ice level control Replace or clean ice level control Shortage or too soft water See remedies for shortage of water or install a mineral salt metering device2nd LED glows High head pressure Dirty condenser. Clean Inoperative fan motor. Replace3rd Yellow LED blinks Too high evap. temperature Check and charge refrigerant system3rd Yellow LED glows Shortage or lack of refrigerant Gear motor tends to run on reverse Check gear motor capacitor Too low gear motor rotating speed Check rotor bearings, freezer bearings and interior of freezer for scores. Replace No rotation of gear motor whatever is worn or damaged. Check for power to drive motor (16 A Gear motor starts and stops fuses) Check for stator windingCompressor cycles intermittently Low voltage Check for correct operation of drive after a while motor magnetic sensorLow ice production Non-condensable gas in system Check for correct magnetic capacity ofWill not dispense Compressor starting device with loose magnetic cylinder wires Check circuit for overloading Capillary tube partially restricted Check voltage at the supply to the building. If low, contact the power Moisture in the system company Low water level in the freezer Purge the system Shortage of refrigerant Check for loose wires in starting device Pitted or stained auger surface Dispense motor open Blow charge, add new gas & drier, after No power to dispense motor evacuating system with vacuum pump Same as above Control board does not work Adjust to approx 20mm below ice spout Open harness Check for leaks & recharge Defective sensor Clean or replace auger Check windings Check harness connections from touch free sensors to control board & from board to motor Trace harness from touch free sensors to PC board, jump the two center pins, the dispense motor should turn. If not replace the board Check the harness for continuity, if any wire is open, replace the harness If the above does not prove to be a problem, replace the sensors May 2002 Page 19

MDT2SERVICE DIAGNOSISSYMPTOM POSSIBLE CAUSE SUGGESTED CORRECTIONWet ice Ambient temperature too high Move unit to cooler locationMachine runs but makes no ice High water level in the freezer Lower to approx. 20mm below ice spoutWater leaks Faulty compressor ReplaceExcessive noise or chattering Water not entering in the freezer Air lock in feed line to freezer. Clogged feed line to freezer. Clean itGear motor noise Gear stripped Check and repair Moisture in the system Purge, replace drier and re-chargeShortage of water Water seal leaking Replace water seal Water feed line to freezer leaking Check and fasten hose clamp Float valve not closing Check and adjust float valve setting screw Mineral or scale deposit on auger Remove and manually polish auger and inner freezer walls and inner walls of Low suction pressure freezer barrel using emery paper Add refrigerant to increase suction Water feed line to freezer clogged pressure Low water level into freezer Vent and clean it Adjust to approx. 20 mm below ice Worn rotor bearings spout Shortage or poor lubricant in gear case Check and replace Check for proper lubricant level by Gear case bearings and gear racers worn opening gear case. out Top of gears must be covered with Strainer at water inlet fitting clogged lubricant Float reservoir water nozzle clogged-up Check and replace worn parts nozzle Remove strainer and clean Remove float valve and clean May 2002 Page 20

MDT2MAINTENANCE AND CLEANING INSTRUCTIONA. GENERAL 8. Check for water leaks and tighten drain line connections. Pour water into the sink to be sureThe times and the procedures for maintenance and that drain line is open and clear.cleaning are given as guides and are not to beconstrued as absolute or invariable. Cleaning 9. Check the ice level control sensor to testespecially will vary depending upon local water and shut-off. Put your hand between the light sourceambient conditions and the ice volume produced. and the receiver on the upper side of the storageEach ice machine must be maintained individually, bin to cut off the light beam for at least 6 seconds.in accordance with its particular locationrequirements. This should cause the 1st RED LED on the front of the PC board to turn off and, 6 seconds later theB. ice machine ice machine will cease operation and the 6th YELLOW LED will turn on. Once you remove yourThe following maintenance should be scheduled at hand the ice machine should resume normalleast two times per year on these ice machines: operation within a few seconds.1. Check and clean the water line strainer or filter. NOTE: The ice level control uses a device that senses light, therefore they must be kept clean2. Remove the cover from the float reservoir – be enough so they can “see”.careful to not damage the two water sensors –anddepress the float to make sure that a full stream of Every month clean/wipe the sensing “eyes” with awater enters the reservoir. clean soft cloth.3. Check that the ice machine is level. 10. Check for refrigerant leaks and for proper frost line, approx. 8 inches from the compressor.4. Check that the water level in the water reservoiris below the overflow but high enough that it does When in doubt of refrigerant charge, connectnot run out of the spout opening. refrigerant gauges to corresponding Schräder valves and check for correct refrigerant pressures.NOTE: The float must stop the incoming water flow (See Operating Pressure on page 19 of thiswhen the rubber housed in the setting screw is manual).perpendicular to the water nozzle. 11. Check that fan blades move freely and are not5. Clean the water system, water reservoir and the touching any surfaces.interior of freezing cylinder using a solution ofSCOTSMAN Ice Machine Cleaner. Refer to 12. Remove the ice spout cover, loosen the boltsection C. CLEANING INSTRUCTIONS OF securing the casting ice sweep and remove it; thenWATER SYSTEM for cleaning procedures and inspect the top bearing. Wipe away existingafter cleaning will indicate frequency and grease and apply a coating of food gradeprocedure to be followed in local areas. waterproof grease (P/N F263612-00).NOTE: Cleaning requirements vary according to NOTE: Use of food-grade, waterproof grease tothe local water conditions and individual user lubricate the top bearing is recommended.operation.6. If required, polish the two sensor rods secured 13. Turn the ice-dispensing spout and remove it.to the float reservoir cover. Heavy scale sediment Wash and sanitize it.on them can be removed with the help of a bit ofSCOTSMAN Cleaner plain. 14. Remove the sink grill for washing and sanitizing.7. With the ice machine and fan motor OFF cleancondenser using vacuum cleaner, whiskbroom ornon-metallic brush taking care to do not damagethe condenser temperature sensor.May 2002 Page 21

MDT2CLEANING INSTRUCTIONS OF WATER SYSTEM1. Switch OFF the power supply to the MDT2. If this should occur it is recommended that you stop the ice machine for few minutes in order to2. Remove the top panel and the top cover of the allow the ice in the freezer to partially melt.storage bin with the dispensing drive motor. 12. When all of the cleaning solution has been3. Remove all ice stored in the bin to prevent it used up, open the water shutoff valve to allow newfrom getting contaminated with the cleaning fresh water to flow into the reservoir. Let the unitsolution. continue to run until the ice resumes the normal color and hardness.4. Close the water shutoff valve on water line. 13. Stop the ice machine and pour warm water on5. Remove the left side panel to gain access to the the ice deposited into the storage bin to melt it.water reservoir. NOTE: DO NOT use ice produced with the6. Remove the float reservoir cover and jump the cleaning solution. Be sure none remains in the bin.two water level sensors with a piece of copperwire.7. Remove the right service panel and loosen the SANITATIONdrain plug from the water purge tube to drain all ofwater our of the freezer. Then re-plug the purge 14. Pour into the water reservoir locally approvedtube. sanitizer mixed according to the directions for that sanitizer. A possible saniziter can be obtained byCLEANING mixing 1 ounce of liquid household bleach with 2 gallons of warm water.8. Prepare the cleaning solution by diluting it in aplastic container with 2.1 quarts (2 liters) of warm 15. Leave the unit running for approx 10 minuteswater (113°-122°F) with 7 ounces (0.2 liters) of then remove the copper wire used to jump the twoSCOTSMAN Ice Machine Cleaner. sensors for the water level and place the cover back on the float reservoir.WARNING: SCOTSMAN Ice Machine Cleanercontains Phosphoric and Hydroxyacetic acids. NOTE: DO NOT use ice produced with theThese compounds are corrosive and may cause sanitizing solution.burns if swallowed, DO NOT induce vomiting. Givelarge amounts of water or milk and call a Physician 16. With a sponge moistened with a sanitizingimmediately. In case of external contact, flush with solution, wipe clean all bin interior surfaces.water. KEEP OUT OF THE REACH OF CHILDREN9. Pour the cleaning solution into the water REMEMBER: To prevent the accumulation ofreservoir until it reaches the proper level. undesirable bacteria it is necessary to sanitize the interior of the storage bin with an anti-algae disinfectant solution every week.10. After 15 minutes switch ON the Master switchto start the unit.11. Wait till the machine starts to discharge ice,then continue to slowly pour the cleaning solutioninto the water reservoir taking care to maintain thelevel just below the overflow.NOTE: The ice made with the cleaning solution isslushy and colored. It may also loose fluiditycreating some resistance in being elevated andextruded; this situation can be heard by thecreaking noise made by the ice. May 2002 Page 22

REMOVAL AND REPLACEMENT MDT2Bearings, Auger, Water Seal To remove gear reducer. 1. Disconnect power leads and sensor wires fromNote: Metric tools are required for this procedure. motor. 2. Perform steps to remove bottom bearing.Disconnect electrical power. 3. Use a 10 mm socket or box wrench to remove the 5 bolts holding the gear reducer to the unit.1. Remove all panels and the sink assembly. 4. Remove the gear reducer from the unit. Reverse all individual sections to reassemble2. Remove the spout cover. that section except for the top bearing and water seal. See the next page.3. Use a 17mm socket to remove the top boltholding the ice sweep to the auger.4. Use a 13mm socket to remove the four boltsholding the breaker to the auger.5. Lift up to remove breaker.To remove top bearing:6. Remove snap ring from the top of the breaker.7. Turn breaker over and using a ¾” punch or bolt,tap the bearing out from the bottom.To remove auger:8. After removing breaker, pull up on the auger toremove it.To remove water seal or bottom bearing.9. Remove bin cover.10. Disconnect drain and water line from bin.11. Remove nut holding bin to chassis.12. Pull bin out of machine.13. Remove screws holding air deflector to chassisand pull deflector out of the unit.14. Remove screws holding reservoir to bulkheadpanel.15. Remove screws holding bulkhead panel tochassis frame, push panel back several inches.16. Use a 13 mm open end or box wrench andremove the three bolts holding the adapter stand tothe evaporator.17. Lift evaporator up and off the stand.18. Tap water seal and bottom bearing out of theevaporator from the top down.May 2002 Page 23

MDT2 3. The bearing’s inner race must be supported during installation. Make an insertion tool. Use aTOP BEARING REPLACEMENT 5/16 - 18 x 3” bolt, a ¾” copper coupling, two or three washers (one must be less than ¾” OD to goReplacement of the top bearing inside the breaker) and two nuts to hold it together: The MDT2 top bearing is a unique design. It is 5/16” bolt two bearings in one: a flat thrust bearing and a roller bearing. ¾” copper The bearing will separate if not installed coupling properly. Do not attempt to install it unless it is secured as described in these instructions.1. Carefully clean out the breaker, removing anydebris or dirt. If using a new breaker, skip this step.2. Separate the flat-bearing & thrust washer fromthe new roller bearing. Flat bearing Flat WasherThrust WasherNot Shown Large Flat Roller Washer Bearing Roller Bearing Nut for Flat centering washer Nut for tightening Construction of Bearing Insertion Tool ·Place copper coupling onto top of bearing ·Place large washers over coupling and small washer under bottom of bearing. ·Insert bolt through large washers, coupling and bearing. Run one nut into bearing to center the bolt. Add small washer and nuit. Tighten nut finger tight. May 2002 Page 24

MDT2BEARING REPLACEMENT - CONTINUED Tighten finger tight 6. Remove coupling, bolt, washers and nuts. before inserting into breaker 7. The roller bearing is fully seated when it is 13/16” from the top edge of the breaker.Bearing and Tool 8. Thoroughly lubricate the thrust bearing and place it on top of the roller bearing. The inner race of the roller bearing must project through the center of the flat thrust bearing. 9. Install the flat washer (provided with the new bearing) on top of the flat thrust bearing. 10. Return the snap ring to its normal position. 11. Add food grade water resistant grease to the top of the bearing area. 12. Assemble onto auger and secure with the original bolt.4. Add food grade lube to the edges of the breakerwhere the bearing will be inserted.5. Tap the new roller bearing into the breaker usinga plastic mallet.Tap Bearing & Tool into Breaker May 2002 Page 25

MDT2WATER SEALStationary Half1. Insert new water seal into bottom of evaporator.2. Insert new bearing under the water seal, push ortap both in until the bottom of the bearing is flush3. Assemble adapter to evaporator. Tightening themounting bolts will correctly position the bottombearing and bottom seal.Rotating Half1. Remove old rotating half from the auger. Cleanthe mounting area.2. Place a bead of food grade sealant (such asScotsman part number 19-0529-01) onto theshoulder of the auger where the rotating half of thewater seal will be installed.3. Wash the new seal in water. While wet, slip itonto the bottom of the auger, rubber side towardthe auger. Push up until seated against thesealant. Do not allow any sealant to come intocontact with the face of the seal.Bottom of Auger May 2002 Page 26