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Scotsman NM1250R, Service Manual, Page: 2 / 39

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Scotsman NM1250R Service Manual Download Page 2

The NM1250R is designed to fit the following
Scotsman storage bins:

B590 and extensions (with bin top KBT18)
HTB500 or BH500
BH800 using bin top KBT15
BH1000 using bin top KBT16

When installing a new system, check to be
sure that you have everything you need
before beginning: 

Correct Condenser
Correct Bin
Correct Ice Machine
Correct Bin Top (if required)
Correct Precharged line set
Fan Relay kit (if needed)
All kits, legs, and information required for the

specific job.

FOR THE INSTALLER

SPECIFICATIONS: ICEMAKER

+ Minimum Circuit Ampacity is used to determine wire size per National Electric Code. 
The standard finish is enamel sandalwood. A stainless steel panel kit, SPKCMD-1, may be field
installed to convert the unit to a stainless steel finish.

MODEL

DIMENSIONS

(without bin)

H" x W" x D"

NM1250RE-32A

NM1250RE-3A

27 x 30 x 24

same

COND.

TYPE

REM0TE-

AIR

COMP.

H.P.

1.75

same

BASIC

ELECTRICAL

208-230/60/1
208-230/60/3

MINIMUM

CIRCUIT  

A

9.5

na

MAXIMUM

FUSE

SIZE

20

na

ICE

TYPE

NUGGET

same

NM1250R

November, 1988

Page 2

Summary of Contents for NM1250R

Page 1: ...l stackable with kit KSTACK30 an electronic circuit for monitoring ice and water level a thermostatic expansion valve and R 502 as the refrigerant TABLE OF CONTENTS For the Installer Specifications 2 Location 5 Remote Condenser 6 For the Plumber 9 For the Electrician 10 Final Check List 14 Start Up 15 Component Description 16 Operation 18 Maintenance Cleaning 23 Service Diagnosis 26 Removal and Re...

Page 2: ...All kits legs and information required for the specific job FOR THE INSTALLER SPECIFICATIONS ICEMAKER Minimum Circuit Ampacity is used to determine wire size per National Electric Code The standard finish is enamel sandalwood A stainless steel panel kit SPKCMD 1 may be field installed to convert the unit to a stainless steel finish MODEL DIMENSIONS without bin H x W x D NM1250RE 32A NM1250RE 3A 27...

Page 3: ...are designed and manufactured with the highest regard for safety and performance They meet or exceed the standards of UL NSF and CSA Scotsman assumes no liability or responsibility of any kind for products manufactured by Scotsman that have been altered in any way including the use of any part and or other components not specifically approved by Scotsman Scotsman reserves the right to make design ...

Page 4: ...aker Use this valve to determine wire size and type between ice maker and fan motor RT625 Precharged line set 25 R502 RT640 Precharged line set 40 R502 KCMR230 Fan relay kit used when two icemakers are on one two circuit condenser MODEL DIMENSIONS H x W x D USE WITH BASIC ELECTRICAL MINIMUM CIRC AMPACITY SHIPPING WEIGHT RC1051 32A RC1052 32A 27 81 x 22 x 37 94 same 1 NM1250R 1 or 2 NM1250Rs 208 23...

Page 5: ...e bin gasket Install bin top if required follow the directions included with the bin top Note Do not push bin into position but lift it there Pushing a bin especially one with ice in it can cause damage to the legs and the leg mounts Ice Maker The machine is heavy so the use of a mechanical lift is recommended for lifting the machine high enough to install on top of the bin After the unit is place...

Page 6: ...nnecting instructions 1 Each set of precharged refrigerant lines either 25 foot or 40 foot consists of a 3 8 inch diameter liquid line and a 1 2 inch diameter discharge line Both ends of each line have quick connect couplings one end has a schrader valve connection that end goes to the condenser Note The openings in the building ceiling or wall listed in the next step are the minimum sizes recomme...

Page 7: ...out or a definite increase in resistance is felt 4 Using a marker or pen mark a line lengthwise from the coupling union nut to the bulkhead Then tighten the coupling and additional 1 4 turn As the nut turns the line will show when 1 4 turn is made 5 Connect the 3 8 inch liquid line schrader valve end to the remote condenser fitting marked liquid line 6 Connect the other end of the liquid line to t...

Page 8: ...he new ice chute cover then slide the connecting chute down into the hole in the new cover e In the upper unit reinstall the ice chute and cover Remove the upper unit bin control sensors from their circuit board connections Install the relay from the kit in the location illustrated f Install interconnecting wires from the kit between the upper unit circuit board opto purple wire and LED yellow wir...

Page 9: ...ne is of the gravity type and 1 4 inch per foot fall is an acceptable pitch for the drain tubing There should be a vent at the highest point of the drain line and the ideal drain receptacle would be a trapped and vented floor drain Use only 3 4 rigid tubing Storage Bin A separate gravity type drain needs to be run Insulation of this drain line is recommended WATER INLET 3 8 FLARE HAND SHUT OFF VAL...

Page 10: ...erminals for the compressor and the fan motor operates whenever the compressor operates Electrical connections are made at the junction box at the back of the icemaker and at the junction box on the remote condenser The remote condenser must be wired to the icemaker in accordance with local and national electrical codes with a minimum of 18 Awg wire with an ground bonding wire connected to the gro...

Page 11: ...ervices of a licensed electrician will be required 1 Mount the control box in a convenient location 2 Attach a solid earth ground wire to the ground screw 3 Route connecting wires from the first ice maker junction box marked condenser fan and connect it to the KCMR230 terminal strip marked NO 1 ICE MACHINE 4 Route connecting wires from the second machine junction box marked condenser fan and conne...

Page 12: ... must be operating for this test Do this after start up 2 Test with a volt meter between terminals 2 and 4 then between terminals 1 and 3 Compare the readings obtained to the ones in the following list C Test terminals 1 2 Full Voltage 208 230 Test terminals 1 3 No voltage Test terminals 2 3 Full Voltage Test terminals 2 4 No voltage Test terminals 3 4 Full voltage Test terminals 1 4 Full voltage ...

Page 13: ...NSULATED PRECHARGED REFRIGERANT TUBING A typical installation should generally appear as illustrated below The remote condenser must be located above the icemaker and the precharged lines installed per the instructions on page 6 NM1250R November 1988 Page 13 ...

Page 14: ... psig 7 Has the machine been secured to the bin 8 If stacked has the stacking kit been installed 9 Is there a water shut off valve installed near the machine 10 Is the remote condenser installed per local building codes and in a place where it has adequate ventilation and minimal solar heat gain 11 Has all shipping material under and next to the gearmotor and on top of the ice chute and literature...

Page 15: ... the start reset switch The electrical start up sequence is now on automatic A There should be a short 15 second delay before the gearmotor starts B After the gearmotor starts the liquid line valve will open the pump down control will close and the compressor will start 5 The remote condenser fan turns and the condenser begins to discharge warm air 6 The unit should soon be making ice if desired t...

Page 16: ... water level sensor Water Level Sensor Senses if there is water in the reservoir to make ice out of Will shut the machine off it there is none Ice Discharge Chute Directs the ice produced by the evaporator into the storage bin Ice Level Sensor An electronic eye it senses the presence of ice in the bottom of the ice discharge chute Operates to turn the ice machine on and off automatically as the le...

Page 17: ...e valve Transformer Supplies low voltage to the circuit board Pump Down Control A switch to control the compressor depending upon low side pressure closes at 18 PSIG and opens at 8 PSIG Potential Relay The compressor start relay On Off Switch Manual control for the machine Reset Switch Manual reset Glows when the unit shuts off from ice discharge chute being overfilled opening the microswitch at t...

Page 18: ...ure The pump down pressure control opens The compressor contactor opens The compressor stops The auger motor is run by the circuit board for 2 5 more minutes clearing out ice in the evaporator and then The auger motor relay opens and the auger motor stops If the ice level sensor is clear bin empty for more than 15 seconds the machine will start up again Another purpose of the circuit board is to t...

Page 19: ... 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 RESERVOIR EVAPORATOR DRAIN WATER LEVEL STRAINER WATER INLET DRAIN ADJUSTMENT OF THE WATER LEVEL NM1250R November 1988 Page 19 ...

Page 20: ...nsion valve meters liquid refrigerant into the evaporator the volume of liquid refrigerant depending upon the temperature of the evaporator warmer evaporators get more refrigerant and colder evaporators get less At the evaporator the refrigerant enters an area of relatively low pressure where it can easily boil off or evaporate As it evaporates it absorbs heat from the evaporator and whatever is i...

Page 21: ...es more refrigerant into the condenser with a small amount of discharge gas going into the receiver to maintain pressure until the head pressure is built back up to the rated gauge pressure of 220 psig At that pressure the valve opens up the liquid line from the condenser to the receiver LIQUID LINE DISCHARGE LINE HEAD PRESSURE CONTROL VALVE RECEIVER HIGH PRESSURE CONTROL SWITCH COMPRESSOR EVAPORA...

Page 22: ...h the head pressure control and into the receiver At this point the refrigerant flow is stopped by the closed liquid line valve This action forces the refrigerant into the receiver and keeps it out of the compressor The pump down continues until the pump down control opens turning the compressor off REMOTE CONDENSER LIQUID LINE VALVE CLOSED COMPRESSOR RECEIVER LIQUID LINE DISCHARGE LINE NM1250R No...

Page 23: ...d Hydroxyacetic acids These compounds are corrosive and may cause burns If swallowed DO NOT induce vomiting Give large amounts of water or milk Call Physician immediately In case of external contact flush with water KEEP OUT OF THE REACH OF CHILDREN 7 Prepare the cleaning solution Mix eight ounces of Scotsman Ice Machine Cleaner with three quarts of hot water The solution should be between 90 and ...

Page 24: ...lean of mineral buildup 3 The top bearing in the breaker should also be checked at least two times per year Check the thrust bearing by removing the ice chute cover unscrewing the ice sweep removing the water shed using a spanner wrench and unscrewing the breaker cover unscrewing the auger stud Inspect the assembly looking for wear 4 Clean the remote condenser Use a vacuum cleaner or coil cleaner ...

Page 25: ... auger remove front and top panels If top panel cannot be removed or if there is less than 6 clearance over the top of the machine the gearmotor evaporator may be slid out for service access See Removal and Replacement 2 Remove 3 hex studs holding the ice chute cover to the ice chutebody and remove the cover 3 Unscrew and remove ice sweep 4 Loosen band clamp under ice chute and remove ice chute bo...

Page 26: ...g a head pressure above 220 psig If the unit has the correct charge and the condenser is clean and the refrigerant lines are not kinked or twisted and the condenser is not overheated by external heat loads the head pressure should be under the trip out point of the head pressure control switch If all of the above are found to be good and the machine trips out on high head pressure replace the head...

Page 27: ...ester should be ON if not replace the circuit board If the bin full light on the tester is ON move the tester switch to bin empty the light on the tester should go OFF and the bin empty light on the circuit board should go ON If not replace the circuit board If it does as above and the machine still does not run replace the ice level sensors 3 If the transformer is fine and the no water light is O...

Page 28: ...r and replace in the machine b Check for low charge add some refrigerant if the unit begins to operate normal low side pressure being about 30 psig stop and look for a leak repair replace the drier evacuate and weigh in the nameplate charge If with added charge the unit does not operate Check for a restricted system replace the drier evacuate and weigh in a nameplate charge Check for a Thermostati...

Page 29: ...ifugal switch or the drive motor 4 If the compressor relay on the circuit board has power on the NO contact but not on the COM contact replace the circuit board C Check the compressor contactor 1 If the liquid line valve is open and the gearmotor is running the low pressure control shoud be closed and the compressor contactor should be energized If not a Check for power at the gearmotor terminal t...

Page 30: ...be restricted defective or not adjusted properly If needed replace the TXV evacuate and recharge per nameplate 4 Check the insulation on the evaporator It should be dry with no wet spots or frost If the insulation has failed replace the evaporator or add extra insulation in the form of foam tape to the evaporator C Check the compressor 1 The compressor may be inefficient a Check the amp draw if lo...

Page 31: ...maker 8 Reverse to reassemble BIN CONTROLS Ice Level Sensors 1 Disconnect electrical power 2 Remove front panel 3 Remove control box cover 4 Locate ice chute at the base of the chute in front of and behind it are two plastic bin control mounts 5 Slide each bin control to the left and in the control box disconnect the electrical leads connecting the bin control to the circuit board 6 Reverse to rea...

Page 32: ...breaker to evaporator d Lift up and remove breaker bearing assembly from auger evaporator 6 Service the bearing Check for rust rough spots and damage a The bearing is pressed into the breaker to remove the bearing and replace it an arbor press is needed b Replace lower seals before installing new bearing in breaker Note seals must be pressed in with a tool pushing against the outer edge only they ...

Page 33: ...uger a Use spanner wrench and unscrew stainless breaker cover from breaker left hand threads b Unscrew auger stud from top of auger c Unscrew 4 allen head cap screws holding breaker to evaporator d 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 a The auger body It should be clean and shi...

Page 34: ...er shoulder and the silastic CAUTION Do not get any silastic onto the face of the seal 6 Allow the auger and seal to air dry until the silastic is dry on the surface 7 If the original water seal was leaking it would be a good idea to inspect the interior of the gearmotor To Replace the Evaporator Assuming all the steps for removal of the thrust bearing breaker auger and water seal have been perfor...

Page 35: ...nk the valve body 7 Sweat in the new valve and the new dryer 8 Evacuate the system and weigh the nameplate charge into the receiver CHARGING PROCEDURES Extra care must be taken when recharging this remote system No liquid refrigerant maybe placed in the system at the compressor DO NOT use the schrader valves at the front of the unit for weighing in the charge All liquid refrigerant must be weighed...

Page 36: ... of water in the oil rusty bearings and gears the oil having a creamy white appearance oil level too high carefully inspect the bearings and gears If in doubt about the condition of a part replace it The oil quantity is 14 fluid ounces do not overfill Note The gears and bearings are available only as pressed together sets D After replacing parts as required if any reassemble the gearcase The two s...

Page 37: ...CH DRIVE MOTOR MOTOR BEARING SHAFT SEAL 1ST GEAR AND BEARINGS 2ND GEAR AND BEARINGS GASKET GEARCASE GEARCASE COVER OUTPUT SHAFT OUTPUT GEAR AND BEARINGS OUTPUT SHAFT SEAL REMOVAL AND REPLACEMENT Gearmotor NM1250R November 1988 Page 37 ...

Page 38: ... Note All testing is done with the electrical power on the master switch on and all reset switches reset 1 Unplug photo trans and LED connectors from the circuit board 2 Plug photo trans and LED connectors from the tester into the circuit board a Move the bin full switch on the tester to Full The light on the tester should be ON If the light on the tester is not on the circuit board should be repl...

Page 39: ...r 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 ELECTRONIC CONTROL TESTER LIGHT ON WATER SENS SWITCH TO NO WATER LIGHT OFF SWITCH TO WATER NM1250R November 1988 Page 39 ...

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