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Scotsman NME1250R, Руководство по обслуживанию

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Scotsman NME1250R Скачать руководство пользователя страница 17

OPERATION: Refrigeration

LOW CONDENSING TEMPERATURE

The refrigeration system under low condenser air
temperatures is much the same as it is under
higher temperatures, with the exception that the
resulting low head pressures cause the head
pressure control to close off the liquid line between
the condenser and the receiver.  

This forces 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 180 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

COMPRESSOR

LIQUID LINE

VALVE

DETAIL OF HEAD

PRESSURE CONTROL

VALVE

EVAPORATOR

THERMOSTATIC

EXPANSION

VALVE

REMOTE CONDENSER

NME1250R

August  1993

Page 17

Содержание NME1250R

Страница 1: ...stallation 9 FOR THE INSTALLER Final Check List 10 START UP 11 COMPONENT DESCRIPTION 12 ELECTRICAL SEQUENCE 14 OPERATION 15 MAINTENANCE AND CLEANING 19 ICEMAKER MAINTENANCE 20 SERVICE DIAGNOSIS Condition No Ice Being Produced 22 SERVICE DIAGNOSIS Condition Low Ice Production 26 REMOVAL AND REPLACEMENT 27 REMOVAL AND REPLACEMENT Bearing And Breaker 28 REMOVAL AND REPLACEMENT Auger 29 REMOVAL AND RE...

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Страница 3: ...the machine outside of the limitations is misuse and can void the warranty Scotsman Ice Systems 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 ot...

Страница 4: ...he 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 plac...

Страница 5: ...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 recommended for passing the refrigerant ...

Страница 6: ...ing the couplings together by hand then using two wrenches it is important that ONLY the nut on the precharged lines be turned the other parts of the couplings must NOT be allowed to turn or the process will tear out the diaphragms and they will be loose in the refrigeration system tighten the coupling until it bottoms out or a definite increase in resistance is felt 5 Using a marker or pen mark a...

Страница 7: ...ine 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 VA...

Страница 8: ... terminals 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 g...

Страница 9: ...INSULATED 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 NME1250R August 1993 Page 9 ...

Страница 10: ...r pressure a minimum of 20 psig 7 Has the machine been secured to the bin 8 Is there a water shut off valve installed near the machine 9 Is the remote condenser installed per local building codes and in a place where it has adequate ventilation and minimal solar heat gain 10 Has all shipping material under and next to the gearmotor and on top of the ice chute and literature inside the front panel ...

Страница 11: ... 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 the low side pressure can be checked it should be 30 psig or 4 p...

Страница 12: ...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 level of ice in the bin changes Gear Motor An oil filled speed reduction gearbox driving the auger ...

Страница 13: ...r with a built in time delay to clear the evaporator of ice when the unit turns off and for the liquid line 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 30 PSIG and opens at 15 PSIG Potential Relay The compressor start relay On Off Switch Manual control for the machine PUMP DOWN CONTROL S...

Страница 14: ...he sensors for more than 15 seconds bin full At that point the machine shuts down Shut Down consists of The liquid line solenoid relay opens lowering the suction pressure The pump down pressure control opens The compressor contactor opens The compressor stops The auger motor is run by the circuit board for 2 more minutes clearing out ice in the evaporator and then The auger motor relay opens and t...

Страница 15: ...evaporator condensation is routed to the drain RESERVOIR EVAPORATOR DRAIN WATER LEVEL STRAINER WATER INLET DRAIN Water Level The correct water level should be checked when the machine is making ice Locate the water level in the reservoir and compare it to he horizontal line molded into the side of the reservoir The correct level should be between 1 8 above and 1 4 below the line If needed bend the...

Страница 16: ...mostatic expansion 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 ...

Страница 17: ...r and the receiver This forces 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 180 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 COMPRESSOR LIQUID LINE VALVE DETAIL OF HEAD PRE...

Страница 18: ...gh 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 NME1250R ...

Страница 19: ...pour the cleaning solution into the water reservoir until it is full Wait 15 minutes then switch the master switch to ON 9 As the ice maker begins to use water from the reservoir continue to add more cleaning solution to maintain a full reservoir 10 After all of the cleaning solution has been added to the reservoir and the reservoir is nearly empty switch the master switch to OFF 11 After draining...

Страница 20: ... of mineral build up 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 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 if needed Do NOT use a wire br...

Страница 21: ...nels 2 Remove bail clip holding the ice chute cover to the ice chute body and remove the cover 3 Unscrew and remove ice sweep 4 Remove ice chute body from evaporator 5 Remove 4 allen screws holding breaker to evaporator 6 Pull up on breaker to remove auger Allow the auger to dry the stainless steel of the auger and evaporator must be clean and bright Clean the auger and evaporator as required DO N...

Страница 22: ...or the air around it kept cooler Check the fan motor for tight bearings and proper rotation Check that the fan blades are clean and the fan secure to the fan motor shaft b Check the head pressure control valve it should be maintaining a head pressure above 180 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...

Страница 23: ... the tester 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 ligh...

Страница 24: ...gerant if the unit begins to operate normal low side pressure being about 30 32 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 Thermostatic Expansion Valve that does not open if defective replace it Re...

Страница 25: ...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 should be closed and the compressor contactor should be energized If not a Check for power at the gearmotor terminal ...

Страница 26: ...ed 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 normal is about ...

Страница 27: ... reservoir from icemaker 9 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 boa...

Страница 28: ...r 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 will not install by hand Replace parts as required Re grease bearing with Scotsman part no A29123 001 bearing grease Rep...

Страница 29: ... 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 shining Sometimes an auger will appear clean when wet but after it is dry it will be seen to be stained Scrub the auger with ice machine cleaner and hot water Ice machine cleaner is an ac...

Страница 30: ...nd pull the water seal down against it 3 The part of the water seal that rotates with the auger must also be replaced Remove the old part from the auger and clean the mounting area 4 Place a small bead of food grade silastic sealant such as 732 RTV or Scotsman part number 19 0529 01 on the area of the auger where the water seal is to be mounted 5 Carefully push the water seal rubber side against t...

Страница 31: ... is in place between the gearcase cover and the drip pan gasket Torque the bolts to 110 inch pounds 2 Lower the auger into the evaporator barrel slightly turning it to match up with the drive end Do Not Drop Into the Evaporator 3 Complete the reassembly by reversing the disassembly for the breaker thrust bearing assembly REMOVAL AND REPLACEMENT Evaporator CHARGING PROCEDURES Extra care must be tak...

Страница 32: ... If there is evidence 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 t...

Страница 33: ...k with the leak detector manufacturer if in doubt As with any other refrigerant do NOT mix HP62 with pressurized air when leak testing VAPOR VAPOR TEMP PRESSURE TEMP PRESSURE DEG F PSIG DEG F PSIG 20 17 70 146 18 18 72 150 16 20 74 155 14 21 76 161 12 23 78 166 10 24 80 171 8 26 82 177 6 28 84 182 4 29 86 188 2 31 88 194 0 33 90 200 2 35 92 206 4 37 94 212 6 39 96 219 8 41 98 225 10 43 100 232 12 ...

Страница 34: ... repaired This system has a critical charge it must be recharged with the correct amount of refrigerant as listed on the nameplate of the ice machine or performance will suffer Anytime the refrigeration system has been opened the dryer should be replaced Note Only a HFC type dryer should be used When brazing the tubing connections to components such as the TXV the component must be protected by he...

Страница 35: ... 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 replaced b If the light on the tester IS on move the bin full 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 the machine still does not run replace the i...

Страница 36: ...ter 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 NME1250R June 1994 Page 36 ...

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