NME1250 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 system. The NME1250 features: front service for the evaporator, gearmotor, control box, water reservoir and bin control; electronic circuitry for monitoring ice and water level; a thermostatic expansion valve; and HP62 as the refrigerant.
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NME1250 FOR THE INSTALLER: Environmental Limitations Installation Limitations: This ice system is designed to be installed indoors, in a controlled environment: Min. Max. Air Temperature 500F 1000F Water Temperature 400F 1000F Water Pressure 20 psi 80 psi Voltage -5% +10% (Compared to the nameplate) Operating the machine outside of the limitations is misuse and can void the warranty.
NME1250 FOR THE INSTALLER Location LEVEL THE ASSEMBLY After uncrating and inspection, the unit is ready for installation. It is important that the machine be installed in a location where it has enough space around it to be accessible for service, and minimum of 6" be allowed to the left, right and top for air circulation on air cooled models. Try to avoid hot, dirty and crowded locations. Be sure that the location for the machine is within the limitations described on page 3.
NME1250 FOR THE PLUMBER CONFORM TO ALL APPLICABLE CODES Water Inlet Drains Air Cooled Models: The recommended water supply is cold water. Use 3/8" O.D. copper tubing, connect to the 3/8" male flare at the back of the cabinet. Install a hand valve near the machine to control the water supply. Air Cooled Models: There is one 3/4" FPT drain at the back of the cabinet, the drain line is of the gravity type, and 1/4 inch per foot fall is an acceptable pitch for the drain tubing.
NME1250 FOR THE ELECTRICIAN CONFORM TO ALL APPLICABLE CODES The electrical power to the unit is supplied through 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.
NME1250 FOR THE INSTALLER: Final Check List 1. Is the ice system installed indoors in a location where the air and water temperatures are controlled, and where they do not exceed the design limitations? 2. Is there an electrical service disconnect within sight of the installed machine? Has the voltage been checked, and compared to nameplate requirements? LEVELED? POWER SUPPLY? 3. Have all the plumbing connections been made and checked for leaks? 4. Has the machine and bin been leveled? 5.
NME1250 START UP Pre-Start Inspection 1. Remove the front, and left side service panels. 2. Check that the styrofoam shipping blocks under the gearmotor, on top of the ice discharge chute, and between the gearmotor and the right side panel have been removed. 3. 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 turns freely (air cooled). 4.
NME1250 COMPONENT DESCRIPTION Control Box: Contains the electrical controls that operate the machine. Low Pressure Cut Out: "A" models only: A manual reset switch set to shut the machine off should the low side pressure go below 0-4 psig. High Pressure Cut Out: A manual reset switch sensing the high side refrigeration pressure. It is set to shut the machine off at 450 psig. Evaporator: A vertical stainless steel tube, refrigerated, and water filled. In it, there is a stainless steel auger.
NME1250 COMPONENT DESCRIPTION: Control Box Contactor: A definite purpose contactor connecting the compressor to the power supply. Circuit Board: Controlling the ice machine through sensors and relays. The sensors are: ice level, and water level. The relays are for the gear motor (with a built in time delay to clear the evaporator of ice when the unit turns off) and for the compressor. Transformer: Supplies low voltage to the circuit board.
NME1250 COMPONENT DESCRIPTION Evaporator: A refrigerated vertical tube filled 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.
NME1250 ELECTRICAL SEQUENCE: "A" Models Refer the wiring diagram as needed. If the machine is switched off at the master switch, but is otherwise ready to go, switching the master switch to on and pressing the start reset switch does the following: • The bin empty light on the circuit board goes on • There is a 15 second delay • If there is enough water in the reservoir, the circuit board will allow the machine to start up.
NME1250 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 or evaporator condensation is routed to the drain.
NME1250 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.
NME1250 CLEANING & SANITIZING A Scotsman Ice System represents a sizable investment of time and money in any company’s business. In order to receive the best return for that investment, it MUST receive periodic maintenance. 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.
NME1250 MAINTENANCE 1. 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 base of the ice chute, and wipe the inside clean, as illustrated. 2. 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.
NME1250 MAINTENANCE: Auger ALLEN HEAD SCREWS Hazardous Moving Parts. Moving auger can cause personal injury. Disconnect electrical power before beginning. In some installations the water supply to the icemaker will be so concentrated with dissolved minerals, (such as calcium carbonate) that as ice is made, the evaporator and auger become coated with the minerals, requiring a more frequent cleaning than twice per year.
NME1250 SERVICE DIAGNOSIS: Condition - No Ice Being Produced STATUS: NOTHING OPERATES A. Check: Voltage to the unit, restore it if there is none. Compare to the nameplate. B. Check: The master switch, switch ON if off. C. Check: The reset switches, (high and low pressure): depress and release each switch. If the still does not start, check the high and the low side pressures. D.
NME1250 SERVICE DIAGNOSIS: Condition - No Ice Being Produced STATUS: NOTHING OPERATES G. Check: The gear motor, if it will not run, the compressor will not run. If no power to it: Check: The indicator lights on the circuit board, the bin empty light should be ON, the no water light should be OFF . 1. If the bin empty and no water lights are off, check the transformer. a. Transformer "load" side should have 12 to 15 volts. If not, check the "line" side. The line side should have between 208-230 volts.
NME1250 SERVICE DIAGNOSIS: Condition - No Ice Being Produced STATUS: GEARMOTOR OPERATES, COMPRESSOR DOES NOT A. Check the compressor relay. The relay is on the circuit board, if it does not supply power to the contactor coil, the compressor will not run. 1. Check for power at the contactor coil, if none: a. Check for power at the compressor relay at the circuit board. If there is power at the relay, but none at the contactor coil, Check for an open wire between the relay and the contactor. 2.
NME1250 SERVICE DIAGNOSIS: Condition - Low Ice Production STATUS: EVERYTHING IS OPERATING A. Check the air cooled condenser for dirt. Clean as required. Check the head pressure on water cooled. Adjust as required. If the head pressure is very high: 1. Air cooled. Check for high air temperatures, or restrictive air flow. Correct as needed. 2. Water cooled. Check for high water temperatures, or low water pressure. Correct as needed. 3.
NME1250 REMOVAL AND REPLACEMENT: Water Reservoir & Bin Control WATER RESERVOIR 1. Shut off the water supply to the icemaker. 2. Remove front panel and reservoir cover. 3. Disconnect water inlet compression fitting at reservoir inlet. 4. To remove float valve, push in on locking tab and lift float valve out of reservoir tank. Note: there is a plunger inside the float valve that is available separately. 5. To remove reservoir, remove drain hose from reservoir. 6. Remove evaporator inlet hose from reservoir.
NME1250 REMOVAL AND REPLACEMENT: Bearing And Breaker Note: Removal of the auger, water seal, evaporator and gearmotor must begin at the top of the assembly. Hazardous Moving Parts. Moving auger can cause personal injury. Disconnect electrical power before beginning. To Remove the Breaker Bearing Assembly: 1. Remove panels and disconnect electrical power. 2. Push back bail clamp and remove ice chute cover. 3. Unscrew and remove ice sweep. 4.
NME1250 REMOVAL AND REPLACEMENT: Auger 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. Hazardous Moving Parts. Moving auger can cause personal injury. Disconnect electrical power before beginning. 1. The top panel must be removed. 2. Push bail clamp off of ice chute cover, remove ice chute cover. 3. Unscrew ice sweep. 4. Remove ice BREAKER chute body. AND 5.
NME1250 REMOVAL AND REPLACEMENT: Water Seal REMOVAL OF THE WATER SEAL WATER SEAL RETAINING RING 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. 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.
NME1250 REMOVAL AND REPLACEMENT: Evaporator REPLACING THE WATER SEAL PLACE A BEAD OF FOOD GRADE SEALANT HERE 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.
NME1250 REMOVAL AND REPLACEMENT: Gearmotor Electrical Shock Hazard. Electrical power can cause personal injury. Disconnect electrical power before beginning. 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. 2. Unscrew the 4 cap screws holding the gearmotor to the gearmotor plate. 3. Remove the gearmotor from the WATER icemaker. SHED To Inspect the gearmotor.
NME1250 REFRIGERATION SERVICE: R-404a THIS ICE MACHINE USES R-404a (HP62) REFRIGERANT AND POLYOLESTER COMPRESSOR OIL. DO NOT USE MINERAL OIL IN THIS REFRIGERATION SYSTEM. • HP62 is a "Near Azeotrope", and therefore liquid charging is preferred. • When the system is serviced, a special liquid line dryer is required. • Polyolester oil absorbs water very easily, and therefore when the system is opened for service, it must be re-sealed as soon as possible (15 minutes maximum).
NME1250 REFRIGERATION SERVICE Recover, reclaim or recycle refrigerant. The General Information: method chosen is up to the service company. Any Work on the refrigeration system should only be refrigerant placed into a Scotsman ice machine done when it is certain that the system needs must meet ARI spec 700-88. Reclaim programs repair. are available through most refrigerant wholesalers. • Refrain from checking refrigeration Access Valves: To use the access valves: pressures without reason.
NME1250 CIRCUIT BOARD TESTING Electrical Shock Hazard. Electrical power can cause personal injury. Disconnect electrical power before connecting tester. INSTRUCTIONS FOR USING TESTER, (Optional, order part no. A33942-001) (These instructions assume that the unit will not run, and prior investigation of electric power, controls, and mechanical parts indicates that the electronic circuit may be at fault.
NME1250 CIRCUIT BOARD TESTING Water Level 1. Unplug “water sen” connector from control board. 2. Plug “water sen” connector from Scotsman tester into circuit board. a. Move “water” switch on tester to No Water position. The No Water light on the circuit board should go ON. If not, replace the circuit board. b. Move the “water” switch on the tester to the Water position. The No Water light on the board should go OFF. If not replace the circuit board. If the light does go off, replace the water level sensor.
