Scotsman MXG 327, MXG 427, MXG 437 Service Manual

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Scotsman Ice Srl Via Lainate, 31 - 20010 Pogliano M.se - Milano - Italy Tel. +39-02-93960.1 (Aut. Sel.)- Telefax +39-02-93550500 Direct Line to Service & Parts: Phone +39-02-93960350 - Fax +39-02-93540449 Website: www.scotsman-ice.it E-Mail: scotsman.europe@scotsman.it

ISO 9001 - Cert. n. 0080

MXG 327 MXG 427 MXG 437

R 290

Electronic

modular cubers

REV. 07/2018

SERVICE MANUAL

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LED

STATUS

REASON WHY-SIGNIFICATION-SIGNIFICATO

ON STEADY

FIXE

FISSO

UNIT UNDER POWER

SOUS TENSION

IN TENSIONE

ON STEADY

FIXE

FISSO

FREEZING CYCLE

EN RÉFRIGÉRATION

IN CONGELAMENTO

BLINKING

CLIGNOTANT

LAMPEGGIANTE

60 MINUTES DELAY AT START UP – JUMPER J3 OUT

60 MINUTES DE RETARD AU DEMARRAGE – CAVALIER J3 OUVERTE

60 MINUTI RITARDO PARTENZA – CONTATTI J3 APERTI

ON STEADY

FIXE

FISSO

TOO HI DISCHARGE PRESSURE/TEMP

COUPURE HP

FERMATA ALTA TEMP. CONDENSAZIONE

BLINKING

CLIGNOTANT

LAMPEGGIANTE

TOO HI EVAP. TEMP. (> 0C°) AFTER 15' FROM START UP

COUPURE BP (0°C LU PAR LA SONE EVAP, NON ATTEINTE APRES 15' FONCT.)

TEMP. EVAP >0 °C DOPO 15' DA INIZIO CONGELAMENTO

ON STEADY

FIXE

FISSO

UNIT OFF AT BIN FULL

CABINE PLEINE

CONTENITORE PIENO

BLINKING SLOW

CLIGNOTANT LENT

LAMPEGGIANTE LENTO

I/R BEAM CUTTED

FAISCEAU INFRA ROUGE CELLULE NIVEAU GLACE INTERROMPU

RAGGIO INFRAROSSO INTERROTTO

BLINKING FAST

CLIGNOTANT RAPIDE

LAMPEGGIANTE VELOCE

I/R ON AFTER TRIP OFF AT BIN FULL

FAISCEAU INFRA ROUGE CELLULE NIVEAU GLACE ETABLI

RAGGIO INFRAROSSO RIPRISTINATO DOPO FERMATA A CONT. PIENO

ON STEADY

FIXE

FISSO

I/R CALIBRATION DONE

CALIBRATION FAISCEAU INFRA ROUGE CELL. NIVEAU GLACE REALISE’

CALIBRAZIONE RAGGIO INFRAROSSO EFFETTUATA

BLINKING

CLIGNOTANT

LAMPEGGIANTE

UNIT IN CLEANING MODE OR TRIPPING OFF AFTER TEST – JUMPER TEST IN

MACHINE EN MODE DETARTRAGE OU ARRETE APRES LE TEST – CAVALIER TEST FERME’

MACCHINA NELLA FASE LAVAGGIO O FERMA DOPO IL TEST – PONTICELLO TEST CHIUSO

ON STEADY

FIXE

FISSO

BLINKING

CLIGNOTANT

LAMPEGGIANTE

CONDENSER SENSOR OUT OF ORDER

SONDE CONDENSEUR HS

SONDA CONDENSATORE MALFUNZIONANTE

EVAPORATOR SENSOR OUT OF ORDER

SONDE EVAPORATEUR HS

SONDA EVAPORATORE MALFUNZIONANTE

BLINKING ALTERNATIVELY

CLIGNOTANT ALTERNE’

LAMPEGGIO ALTERNATO

I/R SENSOR OUT OF ORDER

SONDE INFRA ROUGE CELLULE NIVEAU GLACE HS

SONDA ALL’INFRAROSSO LIVELLO GHIACCIO MALFUNZIONANTE

PUSH

PUSH > 5" DURING WATER FILLING TO MOVE THE UNIT INTO FREEZING

PUSH > 5" DURING FREEZING TO MOVE THE UNIT INTO DEFROST PUSH > 5" DURING DEFROST TO MOVE THE UNIT INTO FREEZING

PUSH 2" < 5" DURING WATER FILLING TO MOVE THE UNIT INTO CLEANING

PUSH DURING THE 60 MIN START UP DELAY TIME TO BY-PASS IT

APPUI > 5" EN REMPLISSAGE POUR BASCULER LA MACHINE EN REFRIGERATION

APPUI > 5" EN CONGELATION POUR BASCULER LA MACHINE EN DEGIVRAGE APPUI > 5" EN DEGIVRAGE POUR BASCULER LA MACHINE EN CONGELATION

APPUI 2"< 5" EN REMPLISSAGE POUR BASCULER LA MACHINE EN DETARTRAGE

APPUI PENDANT LE RETARD AU DEMARRAGE POUR LE BY-PASSER

PREMERE > 5" DURANTE CARICAMENTO ACQUA PER METTERE LA MACCHINA IN CONGELAMENTO

PREMERE > 5" DURANTE CONGELAMENTO PER METTERE LA MACCHINA IN SBRINAMENTO PREMERE > 5" DURANTE SBRINAMENTO PER METTERE LA MACCHINA IN CONGELAMENTO

PREMERE 2" < 5" DURANTE CARICAMENTO ACQUA PER METTERE LA MACCHINA IN LAVAGGIO

PREMERE DURANTE IL RITARDO ALLA PARTENZA PER BY-PASSARLO

PC BOARD 620462 06/11 – NEW RELEASE – NUOVELLE VERSION – NUOVA VERSIONE

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TABLE OF CONTENTS

Table of contents Specifications MXG 327

Specifications MXG 427 Specifications MXG 437

GENERAL INFORMATION AND INSTALLATION

Introduction Unpacking and Inspection - Ice maker Unpacking and Inspection - Storage bin Location and levelling Electrical connections Water supply and drain connections Final check list Installation practice

OPERATING INSTRUCTIONS

Start up Operatiobnal checks

OPERATING PRINCIPLES (How it works)

Freezing cycle Harvest cycle Control sequence Component description

ADJUSTMENT, REMOVAL AND REPLACEMENT PROCEDURES

Adjustment of the cube size Wiring diagram Service diagnosis

MAINTENANCE AND CLEANING INSTRUCTIONS

General Icemaker Cleaning instructions of water system

2 3 5 7

17 19 20 21

26 27 29

31 31 32

12 13

9 9 9

9 10 10 11 11

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ice making capacity

SPECIFICATIONS

ELECTRONIC CUBER MODEL MXG 327

NOTE. The daily ice-making capacity is directly related to the condenser air inlet temperature, water

temperature and age of the machine. To keep your SCOTSMAN MODULAR CUBER at peak performance levels, periodic maintenance

checks must be carried out as indicated on maintenance section of this manual. Production charts shown are indicating the production of "M" (medium) and "L" (large) models. For

"S" (small) models ice production is approx. 10% lower.

mportant operating requirements:

MIN. Air temperature 10°C (50°F) Water temperature 5°C (40°C) Water pressure 1 bar (14 psi) Electr. voltage variations from voltage rating specified on nameplate -10%

MAX.

40°C (100°F)

35°C (90°F)

5 bars (70 psi)

+10%

10 21

154 152 150 148 146 144 142 140 138 136 134 132 130 128 126 124 122 120 118 116 114 112 110 108 106 104 102 100

98 96 94 92 90 88

Kg.

10 °C

21 15

AIR COOLED MODELS

WA TER TEMPERATURE

AMBIENT TEMPERATURE

ICE PRODUCED PER 24 HRS.

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Page 4

Basic electr. Amps Watts N. of wires Amps. fuse

220230/50/1/50/1 4.9 N.A 1150 21.2 3 x 1.5 mm

16 3 x

-230/50/1 7 3 x

SPECIFICATIONS

MXG 327 - MACHINE SPECIFICATIONS

Starts Electric power cons. amps. Kwh x 24 HR

Cubes per harvest: 72 Large - 106 Medium - 198 Small * At 21°C (70°F) water temperature

MXG 327 AS 6 Air Stainless steel 480* MXG 327 WS 6 Water Stainless steel

Model Cond. unit Finish Water req. - lt/24 HR

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ice making capacity

SPECIFICATIONS

ELECTRONIC CUBER MODEL MXG 427

NOTE. The daily ice-making capacity is directly related to the condenser air inlet temperature, water

temperature and age of the machine. To keep your SCOTSMAN MODULAR CUBER at peak performance levels, periodic maintenance

checks must be carried out as indicated on maintenance section of this manual. Production charts shown are indicating the production of "M" (medium) and "L" (large) models. For

"S" (small) models ice production is approx. 10% lower.

mportant operating requirements:

MIN. Air temperature 10°C (50°F) Water temperature 5°C (40°C) Water pressure 1 bar (14 psi) Electr. voltage variations from voltage rating specified on nameplate -10%

MAX.

40°C (100°F)

35°C (90°F)

5 bars (70 psi)

+10%

172 170 168 166 164 162 160 158 156 154 152 150 148 146 144 142 140 138 136 134 132 130 128 126 124 122 120 118 116 114

Kg.

10 °C

21 15

AIR COOLED MODELS

WA TER TEMPERATURE

AMBIENT TEMPERATURE

ICE PRODUCED PER 24 HRS.

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220-230/50/1 7 1400 26.65 3 x

Basic electr. Amps Watts N. of wires Amps. fuse

230/50/1N 5 39 3 x 1.5 m/m

MXG 427 AS 6 Air Stainless steel MXG 427 WS 6 Water Stainless steel

Model Cond. unit Finish Water req. - lt/24 HR

SPECIFICATIONS

432*

MXG 427 - MACHINE SPECIFICATIONS

Starts Electric power cons.

amps. Kwh x 24 HR

Cubes per harvest: 72 Large - 106 Medium - 198 Small * At 21°C (70°F) water temperature

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ice making capacity

SPECIFICATIONS

ELECTRONIC CUBER MODEL MXG 437

NOTE. The daily ice-making capacity is directly related to the condenser air inlet temperature, water

temperature and age of the machine. To keep your SCOTSMAN MODULAR CUBER at peak performance levels, periodic maintenance

checks must be carried out as indicated on maintenance section of this manual. Production charts shown are indicating the production of "M" (medium) and "L" (large) models. For

"S" (small) models ice production is approx. 10% lower.

mportant operating requirements:

MIN. Air temperature 10°C (50°F) Water temperature 5°C (40°C) Water pressure 1 bar (14 psi) Electr. voltage variations from voltage rating specified on nameplate -10%

MAX.

40°C (100°F)

35°C (90°F)

5 bars (70 psi)

+10%

172 170 168 166 164 162 160 158 156 154 152 150 148 146 144 142 140 138 136 134 132 130 128 126 124 122 120 118 116 114

Kg.

10 °C

21 15

AIR COOLED MODELS

WA TER TEMPERATURE

AMBIENT TEMPERATURE

ICE PRODUCED PER 24 HRS.

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220-230/50/1 7 1400 26.65 3 x

Basic electr. Amps Watts N. of wires Amps. fuse

230/50/1N 5 39 3 x 1.5 m/m

SPECIFICATIONS

MXG 437 - MACHINE SPECIFICATIONS

Starts Electric power cons.

amps. Kwh x 24 HR

Cubes per harvest: 72 Large - 106 Medium - 198 Small * At 21°C (70°F) water temperature

MXG 437 AS 6 Air Stainless steel MXG 437 WS 6 Water Stainless steel

Model Cond. unit Finish Water req. - lt/24 HR

432*

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A. INTRODUCTION

This manual provides the specifications and the step-by-step procedures for the installation, startup and operation, maintenance and cleaning for the SCOTSMAN MODULAR CUBERS. The Electronic Modular Cubers are quality designed, engineered and manufactured. Their ice making systems are thoroughly tested providing the utmost in flexibility to fit the needs of a particular user. These icemakers have been engineered to our own rigid safety and performence standards.

NOTE. To retain the safety and performance built into this icemaker, it is important that installation and maintenance be conducted in the manner outlined in this manual.

Storage Bin

Since the MXG series Modular Cubers do not have their own attached ice storage bins, it is necessary to use an auxiliary bin such as:

SB 193 SB 322 SB 393 SB 530.

B. UNPACKING AND INSPECTION Modular Cuber

1. Call your authorized SCOTSMAN Distributor or Dealer for proper installation.

2. Visually inspect the exterior of the packing and skid. Any severe damage noted should be reported to the delivering carrier and a concealed damage claim form filled in subjet to inspection of the contents with the carrier’s representative present.

3. a) Cut and remove the plastic strip securing the carton box to the skid.

b) Remove the packing nails securing the

carton box to the skid.

c) Cut open the top of the carton and remove

the polystyre protection sheet.

d) Pull out the polystyre posts from the

corners and then remove the carton.

4. Remove top and sides panels of the unit and inspect for any concealed damage. Notify carrier of your claim for the concealed damage as stated in step 2 above.

5. Loose two nuts on left and rights side of the unit base and remove it from the skid. Save the two bolts and nuts to mount the machine on storage bin or on top of another Modular Cuber.

GENERAL INFORMATION AND INSTALLATION

6. Remove all internal support packing and masking tape and the hardware package.

7. Check that refrigerant lines do not rub against or touch other lines or surfaces, and that the fan blade moveS freely.

8. Check that the compressor fits snugly onto all its mounting pads.

9. See data plate on the rear side of the unit and check that local main voltage corresponds with the voltage specified on it.

CAUTION. Incorrect voltage supplied to the icemaker will void your parts replacement program.

10. Remove the manufacturer’s registration card from the inside of the User Manual and fillin all parts including: Model and Serial Number taken from the data plate. Forward the completed self-addressed registration card to Scotsman Ice srl.

C. LOCATION AND LEVELLING

WARNING. This Ice Cuber is designed for indoor installation only. Extended periods of operation at temperature exceeding the following limitations will constitute misuse under the terms of the SCOTSMAN Manufacturer’s Limited Warranty resulting in LOSS of warranty coverage.

1. Position the Bin in the selected permanent location. Criteria for selection of location include:

a) Minimum room temperature 10°C (50°F)

and maximum room temperature 40°C (100°F).

b) Water inlet temperatures: minimum 5°C

(40°F) and maximum 35°C (90°F).

c) Well ventilated location for air cooled

models.

d) Service access: adequate space must be left for all service connections through the rear of the ice maker. A minimum clearance of 15 cm (6") must be left at the sides of the unit for routing cooling air drawn into and exhausted out of the compartment to maintain proper condensing operation of air cooled models.

2. Level the Storage Bin Assy in both the left to right and front to rear directions by means of the adjustable legs.

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D. ELECTRICAL CONNECTIONS

See data plate for current requirements to determine wire size to be used for electrical connections. All SCOTSMAN icemakers require a solid earth wire. All SCOTSMAN ice machines are supplied from the factory completely pre-wired and require only electrical power connections to the wire cord provided at the rear of the unit. Make sure that the ice machine is connected to its own circuit and individually fused (see data plate for fuse size). The maximum allowable voltage variation should not exceed -10% and +10% of the data plate rating. Low voltage can cause faulty functioning and may be responsible for serious damage to the overload switch and motor windings.

NOTE. All external wiring should conform to national, state and local standards and regulations.

Check voltage on the line and the ice maker’s data plate before connecting the unit.

E. WATER SUPPLY AND DRAIN

CONNECTIONS General

When choosing the water supply for the ice modular cuber consideration should be given to:

a) Length of run b) Water clarity and purity c) Adequate water supply pressure

Since water is the most important single ingredient in producting ice you cannot emphasize too much the three items listed above. Low water pressure, below 1 bar may cause malfunction of the ice maker unit. Water containing excessive minerals will tend to produce cloudy coloured ice cubes, plus scale build-up on parts of the water system.

Water supply

Connect the 3/4" GAS male fitting of the solenoid water inlet valve, using flexible tubing or a 3/8" O.D. copper pipe, to the cold water supply line with regular plumbing fitting and a shut-off valve installed in an accessible position between the water supply line and the unit.

Water supply - Water cooled models

The water cooled versions of SCOTSMAN Ice Makers require two separate inlet water supplies, one for the water sprayed for making the ice cubes and the other for the water cooled condenser. Connect the 3/4" GAS male fitting of the water inlet, using the flexible tubing or a 3/8" O.D. copper pipe, to the cold water supply line with regular plumbing fitting and a shut-off valve installed in an accessible position between the water supply line and the unit.

3. Inspect the Storage Bin top mounting gasket which should be flat with no wrinkles, to provide a good sealing when the Modular Cuber is installed on top of it.

4. Place the Modular Cuber on top of Storage bin using care not to wrinkle or tear the gasket.

5. Lift a little bit the Modular Cuber right side in order to be able to mount the ice level control bracket taking care to align the hole located on unit base to mate with the one on the top of the Bin.

6. Remove the PVC plastic plug closing the round hole located on the side of the ice chute opening.

7. Trace the ice level control assy, secured for the transport of the Modular Cuber, and direct it down through the round hole into the Storage Bin.

8. Fasten the ice level control assy on its bracket by means of the two screws found in the hardware package supplied with the unit.

9. Make a cut (shear) in the PVC plastic plug that goes from its edge to the center; insert the ice level control cable in the center of the plastic plug so to prevent it from any sort of contact with the unit frame, then place again the PVC plug in the round hole keeping the cable exceeding portion inside the unit.

10. Place ice level sensor and related bracket as per below figure.

11. Secure the Modular Cuber on the top of the Storage Bin using the two bolts and diber washer found in the hardware package supplied with the unit.

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Water drain

The recommended drain tube is a plastic or flexible tube with 18 mm (3/4") I.D. which runs to an open trapped and vented drain. When the drain is a long run, allow 3 cm pitch per meter (1/4" pitch per foot). A vent at the unit drain connection is also required for proper sump drainage.

Water drain - Water cooled models

Connect the 3/4" GAS male fitting of the condenser water drain, using a second flexible tubing or a 3/ 8" O.D. copper tubing, to the open trapped and vented drain.

NOTE. The water supply and the water drain must be installed to conform with the local code. In some case a licensed plumber and/ or a plumbing permit is required.

F. FINAL CHECK LIST

1. Is the unit in a room where ambient temperatures are within a minimum of 10°C (50°F) even in winter months?

2. Is there at least a 15 cm (6") clearance around the unit for proper air circulation?

3. Is the unit level? (IMPORTANT)

4. Have all the electrical and plumbing connections been made, and is the water supply shut-off valve open?

5. Has the voltage been tested and checked against the data plate rating?

6. Has the water supply pressure been checked to ensure a water pressure of at least 1 bar (14 psi).

7. Have the bolts holding the compressor down been checked to ensure that the compressor is snugly fitted onto the mounting pads?

8. Check all refrigerant lines and conduit lines to guard against vibrations and possible failure.

9. Have the bin liner and cabinet been wiped clean?

10. Has the owner/user been given the User Manual and been instructed on the importance of periodic maintenance checks?

11. Has the Manufacturer’s registration card been filled in properly? Check for correct model and serial number against the serial plate and mail the registration card to the factory.

G. INSTALLATION PRACTICE

1. Hand shut-off valve

2. Water filter

3. Water supply line (flexible hose)

4. 3/4" gas male fitting

5. Power line

6. Main switch

7/9. Drain fitting

8/10. Vented drain line

11. Open trapped vented drain

WARNING. This icemaker is not designed for outdoor installation and will not function in ambient temperatures below 10°C (50°F) or above 40°C (100°F).

This icemaker will malfunction with water temperatures below 5°C (40°F) or above 35°C (90°F).

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OPERATING INSTRUCTIONS

Rx Tx

WATER IN VALVE

HOT GAS VALVE

CONTACTOR COIL

FAN MOTOR

WATER PUMP

- EVAPORATOR

- AMBIENT

- CONDENSER

TEMPERATURE SENSORSBINCOMPRESSOR

TRANSF.

DATA

PROCESSOR

ELECTR.

TIMER

DIP SWITCH

ELECTRONIC CARD

RELAYS

RELAY

TRIAC

WATER DRAIN VALVE

FIG. 1

START UP

After having correctly installed the ice maker and completed the plumbing and electrical connections, perform the following “Start-up” procedure.

A. Give power to the unit to start it up by switching "ON" the power line main disconnect switch.

NOTE.

Every time the unit returns under power, after having been switched off, the water inlet valve, the hot gas valve and the water drain valve get energized for a period of 5 minutes, thus to admit new water to the machine sump reservoir to fill it up and, eventually, to wash-off any dirt that can have deposited in it during the unit off period (Fig.1).

B. During the water filling operation, check to see that the incoming water dribbles, through the evaporator platen dribbler holes, down into the

sump reservoir to fill it up and also that the incoming surplus of water flows out through the overflow pipe into the drain line. During the water filling phase the components energized are:

THE WATER INLET SOLENOID VALVE THE HOT GAS SOLENOID VALVE THE WATER DRAIN SOLENOID VALVE/S

for the first 30 seconds.

NOTE

. If in the 5 minutes length of the water filling phase the machine sump reservoir does not get filled with water up to the rim of the overflow pipe, it is advisable to check:

1.The water pressure of the water supply line that must be at least 1 bar (14 psig) Minimum (Max 5 bar-70 psig).

2.The filtering device installed in the water line that may reduce the water pressure below the Minimum value of 1 bar (14 psig).

3. Any clogging situation in the water circuit like the inlet water strainer and/or the flow control.

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Rx Tx

WATER IN VALVE

HOT GAS VALVE

CONTACTOR COIL

FAN MOTOR

WATER PUMP

- EVAPORATOR

- AMBIENT

- CONDENSER

TEMPERATURE SENSORSBINCOMPRESSOR

TRANSF.

DATA

PROCESSOR

ELECTR.

TIMER

DIP SWITCH

ELECTRONIC CARD

RELAYS

RELAY

TRIAC

WATER DRAIN VALVE

FIG. 2

C. At completion of the water filling phase (5

minutes) the unit passes automatically into the freezing cycle with the start up of:

COMPRESSOR WATER PUMP FAN MOTOR/S (in air cooled version) controlled

by the condensing temperature sensor located within the condenser fins (Fig.2).

OPERATIONAL CHECKS D. If necessary install the refrigerant service

gauges on both the high side and low side Schräder valves to check the compressor head and suction pressures.

NOTE.

On air cooled models, in case of condenser clogging such to prevent the proper flow of the cooling air or, in case the fan motor is out of operation or shortage of water in the water cooled condenser, the condenser temperature rises and when it reaches 70°C (160°F) - for air cooled version - or 60°C (140°F) - for water cooled version - the condenser temperature sensor shuts-off the ice maker with the consequent light-up of the RED WARNING LED (Fig.3).

After having diagnosed the reason of the rise of temperature and removed its cause, it is necessary to unplug (wait few seconds) and plug in again the unit, thus to put the machine in condition to initiate a new freezing cycle.

The machine restarts with the usual 5 minutes water filling phase in order to provide enough water into the sump tank.

E. Check to see through the ice discharge opening that the self propeller spray bar is correctly rotating and that the water jets uniformely reach the interior of the inverted mold cups and there is not excessive water spilling through it.

F. The ice making process takes place thereby, with the water sprayed into the molds that gets gradually refrigerated by the heat exchange with the refrigerant flowing into the evaporator serpentine.

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Rx Tx

WATER IN VALVE

HOT GAS VALVE

CONTACTOR COIL

FAN MOTOR

WATER PUMP

- EVAPORATOR

- AMBIENT

- CONDENSER

TEMPERATURE SENSORSBINCOMPRESSOR

TRANSF.

DATA

PROCESSOR

ELECTR.

TIMER

DIP SWITCH

ELECTRONIC CARD

RELAYS

RELAY

TRIAC

WATER DRAIN VALVE

FIG. 4

Rx Tx

WATER IN VALVE

HOT GAS VALVE

CONTACTOR COIL

FAN MOTOR

WATER PUMP

- EVAPORATOR

- AMBIENT

- CONDENSER

TEMPERATURE SENSORSBINCOMPRESSOR

TRANSF.

DATA

PROCESSOR

ELECTR.

TIMER

DIP SWITCH

ELECTRONIC CARD

RELAYS

RELAY

TRIAC

WATER DRAIN VALVE

FIG. 3

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Rx Tx

WATER IN VALVE

HOT GAS VALVE

CONTACTOR COIL

FAN MOTOR

WATER PUMP

- EVAPORATOR

- AMBIENT

- CONDENSER

TEMPERATURE SENSORSBINCOMPRESSOR

TRANSF.

DATA

PROCESSOR

ELECTR.

TIMER

DIP SWITCH

ELECTRONIC CARD

RELAYS

RELAY

TRIAC

WATER DRAIN VALVE

FIG. 5

During the freezing process, when the evaporator temperature falls below an established value, to the evaporator temperature sensor supplies a low voltage power signal to the electronic control device (P.C.BOARD) in order to activate an electronic timer. This one takes over the control of the freezing cycle up to the complete formation of the ice cubes (Fig.4).

NOTE.

The length of the entire freezing cycle is governed by the evaporator temperature sensor which has its brobe placed in contact with the evaporator serpentine (Non adjustable) in combination with the electronic timer (Adjustable) incorporated in the P.C. BOARD). The timer adjustment is factory set in consideration of the ice maker model, cooling version and ice cube size (Small, Medium, Large). It is possible, however, to modify the timed length of the freezing cycle, by changing the DIP SWITCH keys setting. In Table B of PRINCIPLE OF OPERATION are shown the various time extensions of the freezing cycle second phase, in relation with the different DIP SWITCH keys settings.

G. After about 17-20 minutes from the beginning of the freezing cycle, in an hypothetic ambient temperature of 21°C , the defrost cycle takes place with the hot gas and the water inlet valves being simoultaneously activated (Fig.5). The electrical components in operation are:

COMPRESSOR WATER PUMP for the first 30 seconds WATER INLET SOLENOID VALVE HOT GAS VALVE WATER DRAIN SOLENOID VALVE/S

NOTE. The length of the defrost cycle is

related to the length of the second phase of freezing cycle T2. (Time to drop the evaporating temperature from 0°C (32°F) small Red LED blinking-to-15°C (5°F) small Red LED ON steady.

It is possible to extend the length of the defrost

cycle by changing the setting of DIP SWITCH 7 and 8 as shown on table at page 28.

H. Check, during the defrost cycle, that the incoming water flows correctly into sump reservoir in order to refill it and that the surplus overflows through the overflow drain tube.

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Rx Tx

WATER IN VALVE

HOT GAS VALVE

CONTACTOR COIL

FAN MOTOR

WATER PUMP

- EVAPORATOR

- AMBIENT

- CONDENSER

TEMPERATURE SENSORSBINCOMPRESSOR

TRANSF.

DATA

PROCESSOR

ELECTR.

TIMER

DIP SWITCH

ELECTRONIC CARD

RELAYS

RELAY

TRIAC

WATER DRAIN VALVE

FIG. 6

I. Check the texture of ice cubes just released.

They have to be in the right shape with a small depression of about 5-6 mm in their crown. If not, wait for the completion of the second cycle before performing any adjustment. If required, the length of the timed freezing cycle can be modified by changing the DIP SWITCH keys setting as illustrated in OPERATING PRINCIPLE. If the ice cubes are shallow and cloudy, it is possible that the ice maker runs short of water during the freezing cycle second phase or, the quality of the supplied water requires the use of an appropriate water filter or conditioner.

To be sure of the correct operation of ice level control device, place some ice cubes between its sensing “eyes” to interrupt the light beam. The Bin Full YELLOW LED starts blinking fill the end of defrost cycle afterward, the unit stops with the simultaneous glowing of the same LED to monitor the BIN FULL situation (Fig.6).

Remove ice cubes out from the ice level control sensors to allow the resumption of the light beam. Water inlet valve is energized for 45 seconds to refill the sump, the BIN FULL YELLOW LED blinks fast and after approximately 6 seconds

the ice maker resume its operation with the immediate glowing of the FIRST YELLOW LED indicating UNIT IN OPERATION and the extinguishing of the “BIN FULL” YELLOW LED.

NOTE. The ICE LEVEL CONTROL (INFRARED SYSTEM) is independent of the

temperature however, the reliability of its detection can be affected by external light radiations or by any sort of dirt and scale sediment which may deposit directly on the light source and on the receiver.To prevent any possible ice maker malfunction, due to negative affection of the light detector, it is advisable to locate the unit where it is not reached by any direct light beam or light radiation, also it is recommended to keep the bin door constantly closed and to follow the instructions for the periodical cleaning of the light sensor elements as detailed in the MAINTENANCE AND CLEANING PROCEDURES.

K. Remove, if previously installed, the refrigerant service gauges and re-fit the unit service panels previously removed.

L. Instruct the owner/user on the general operation of the ice machine and about the cleaning and care it requires.

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PRINCIPLE OF OPERATION

How it works

In the SCOTSMAN Modular Cubers the water used to make the ice is kept constantly in circulation by an electric water pump which primes it to the self propeller spray bar nozzles from where it is diverted into the inverted mold cups of the evaporator (Fig. B). A small quantity of the sprayed water freezes into ice; the rest of it cascades by gravity into the sump assembly below for recirculation.

FREEZING CYCLE (Fig. A) The hot gas refrigerant discharged out from the

compressor reaches the condenser where, being cooled down, condenses into liquid. Flowing into the liquid line it passes through the drier filter, then it goes all the way through the capillary tube where, due to the heat exchanging action, it looses some of its heat content so that its pressure and temperature are lowered as well. Next the refrigerant enters into the evaporator serpentine (which has a larger I.D. then the capillary) and starts to boil off; this reaction is emphasized by the heat transferred by the sprayed water. The refrigerant then increases in volume and changes entirely into vapor.

The vapor refrigerant then passes through the suction accumulator (used to prevent that any small amount of liquid refrigerant may reach the compressor) and through the suction line. In both the accumulator and the suction line it exchanges heat with the refrigerant flowing into the capillary tube (warmer), before to be sucked in the compressor and to be recirculated as hot compressed refrigerant gas. The freezing cycle is controlled by the evaporator temperature sensor (which has its probe in contact with the evaporator serpentine) that determines the length of its first portion of the cycle. When the temperature of the evaporator serpentine drops to a pre-set value, the evaporator sensor probe changes its electrical resistance allowing a low voltage current (12 volts) to flow to the P.C. BOARD which in turn activates an electronic timer. The timer, which is built-in the P.C. BOARD, takes over from the evaporator temperature sensor, the control of the freezing cycle up to its completion.

NOTE.

The change of the electric potential of the evaporator sensor with the consequent activation of the timer (Time mode) is signalled by the glowing-up of the RED LED located beside the FREEZING yellow one in the front of the P.C. BOARD.

MXG-S 327 A MXG-S 327 W MXG-M 327 A ON ON OFF ON OFF ON ON ON OFF ON MXG-M 327 W MXG-M 327 W MXG-L 327 A MXG-L 327 W MXG-S 427-437 A MXG-S 427-437 W MXG-M 427-437 A ON ON OFF ON OFF ON ON ON OFF ON MXG-M 427-437 W MXG-L 427-437 A MXG-L 427-437 W

TAB. A

DIP SWITCH FACTORY SETTING COMBINATIONS PER MODEL AND VERSION

DIP SWITCH

12345678910

FREEZING CYCLE

DEFROST

CYCLE

DEFR. CYCLE

ADD. TIME

15/30°

AIR

WATER

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ATTENTION. In case, after 15 minutes from the beginning of the freezing cycle, the temperature of the evaporator sensor probe is higher then 0°C (32°F) (shortage of refrigerant, inoperative hot gas valve, etc.) the P.C. BOARD switch OFF immediately the unit with the simultaneous blinking of the WARNING RED LED.

The length of this second portion of the freezing cycle is pre-fixed and related to the setting of the first four DIP SWITCH keys. The DIP SWITCH keys setting is made in consideration of the type of condenser used. In Table B are indicated the various lengths of the second portion of freezing cycle (Time mode) in relation to the different combinations of the DIP SWITCH KEYS. In Table A herebelow are illustrated the DIP SWITCH key combinations for the three different factory. The electrical components in operation during the freezing cycle are:

COMPRESSOR FAN MOTOR (in air cooled version) WATER PUMP

and during the second phase of freezing cycle (Time mode) they are joined by the

ELECTRONIC TIMER

At average 21°C amb/15°C water temp. t he refrigerant head pressure, in the course of the freezing cycle, ranges between 12 and 10 bars (175-145 psig) being controlled by the temperature sensor probe located within the condenser fins (air cooled version) or, on the condenser tube coil (water cooled version). On the air cooled version, the condenser temperature sensor, when senses a rising of the condenser temperature beyond the pre-fixed limit, changes its electrical resistance and send a low voltage power flow to the Micro Processor of P.C. BOARD which in turn energizes, through a TRIAC, the FAN MOTOR. When the opposite situation occures, i.e. the condenser temperature gets below the pre-fixed limit, the temperature sensor changes again its electrical resistance reducing therefore the current flow to the P.C. BOARD to cause the fan motor temporary cut-off.

NOTE. On this model the condenser sensors are used just to switch off the unit in case the condensing temperature rise up to more then 70°C (for air cooled version) or more then 62°C (for water cooled version) for one of the following abnormal reasons:

CLOGGED CONDENSER (Air cooled version)

FAN MOTOR OUT OF OPERATION (Air cooled version)

INSUFFICIENT FLOW OF COOLING WATER (Water cooled version)

AMBIENT TEMPERATURE HIGHER THEN 40°C (100°F)

it causes the total and immediate SHUT-OFF of the machine in order to prevent the unit from operating in abnormal and dangerous conditions. When the ice maker stops on account of this protective device, there is a simultaneous glowing of the RED LED, warning the user of the Hi Temperature situation. After having efiminated the source of the condenser hi-temperature, to restart the machine just switching OFF and ON the unit at main line switch. The ice machine resumes its normal operation by going through the 5 minutes water filling phase.

MXG refrigerant operating pressures (suction/ discharge) may change according to models. See related table at pag. 25. The total length of the freezing cycle ranges f rom 20 to 25 minutes.

DEFROST OR HARVEST CYCLE (Fig. D) As the electronic timer has carried the system

throughout the second phase of freezing cycle, the defrost cycle starts.

ATTENTION. In case the unit be able to reach 0°C (32° F) evaporating temperature within 15 minutes, but after 45 minutes from the beginning of the freezing cycle it has not yet reached the evaporator temperature of -15°C (5° F) the machine goes straight into the defrost cycle omitting the timed portion of the freezing cycle relied to the setting of the first four DIP SWITCHES.

NOTE. The length of the defrost cycle is

related to the length of the second phase of freezing cycle T2. (Time to drop the evaporating temperature from 0°C (32°F) small Red LED blinking-to-15°C (5°F) small Red LED ON steady.

It is possible to extend the length of the defrost

cycle by changing the setting of DIP SWITCH 7 and 8 as shown on table at page 28.

The electrical components in operation during this phase are:

COMPRESSOR CONTACTOR COIL WATER INLET VALVE HOT GAS VALVE WATER DRAIN VALVE

and the

WATER PUMP

on the first 30 seconds.

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The incoming water, passing through the water inlet valve and the flow control, runs over the evaporator platen and then flows by gravity through the dribbler holes down into the sump/ reservoir (Fig. D). The water filling the sump/reservoir forces part of the surplus water from the previous freezing cycle to go out to the waste through the overflow pipe. This overflow limits the level of the sump water which will be used to produce the next batch of ice cubes. Meanwhile, the refrigerant as hot gas, discharged from the compressor, flows through the hot gas valve directly into the evaporator serpentine bypassing the condenser. The hot gas circulating into the serpentine of the evaporator warms up the copper molds causing the defrost of the ice cubes. The ice cubes, released from the cups, drop by gravity onto a slanted cube chute, then through a curtained opening they fall into the storage bin. At the end of the defrost cycle, both the hot gas and the water inlet valves close and the machine starts again a new freezing cycle.

OPERATION - CONTROL SEQUENCE

At the start of freezing cycle, the evaporator temperature sensor controls the length of the first part of the freezing cycle. As it reaches a predetermined temperature, it supplies a low voltage current to the P.C. BOARD in order to activate the electronic timer which, takes over the control of the freezing cycle for a pre-fixed time, according to the DIP SWITCH keys setting (see Tab. B).

NOTE. The evaporator temperature sensor, factory pre-set, is the same for all the models and is not adjustable.

Once completed the freezing cycle 2nd phase the system goes automatically into the defrost cycle which also has a pre-fixed length. At completion of the defrost cycle the P.C. BOARD commands the unit to start again a new freezing cycle.

OPERATION - ELECTRICAL SEQUENCE

The following charts illustrate which switches and which components are ON or OFF during a partÌcular phase of the icemaking cycle.

BEGINNIING FREEZE

Electrical components (Loads). ON OFF

Compressor.................................. •

Fan Motor (Air cooled only) and TRIAC

•

Hot Gas Valve .............................. •

Inlet Water Valve.......................... •

P.C. Board Relay 1 Coil ............... •

P.C. Board Relay 2 & 3 Coil......... •

Water Pump ................................. •

Electronic Timer ........................... •

Electronic Controls & Sensors .. ON OFF

Evaporator Sensor ....................... •

Condenser Sensor ....................... •

Ice Level Control .......................... •

TIMED FREEZE

Electrical components (Loads). ON OFF

Compressor.................................. •

Fan Motor (Air cooled only) and TRIAC

••

Hot Gas Valve .............................. •

Inlet Water Valve.......................... •

P.C. Board Relay 1 Coil ............... •

P.C. Board Relay 2 & 3 Coil......... •

Water Pump ................................. •

Electronic Timer ........................... •

Electronic Controls & Sensors . ON OFF

Evaporator Sensor ....................... •

Condenser Sensor ....................... • •

Ice Level Control .......................... •

HARVEST (Drain portion - first 30 sec.)

Electrical components (Loads). ON OFF

Compressor.................................. •

Fan Motor (Air cooled only) and TRIAC .

•

Hot Gas Valve .............................. •

Water Inlet Valve.......................... •

Water Drain Valve ........................ •

P.C. Board Relay 1 & 2 Coil......... •

P.C. Board Relay 3 Coil ............... •

Water Pump ................................. •

P.C.B. Timer................................ •

HARVEST (Water filling portion)

Electrical components (Loads). ON OFF

Compressor.................................. •

Fan Motor (Air cooled only) and TRIAC .

•

Hot Gas Valve .............................. •

Water Inlet Valve.......................... •

Water Drain Valve ........................ •

P.C. Board Relay 1 & 2 Coil......... •

P.C. Board Relay 3 Coil ............... •

Water Pump ................................. •

P.C. Board Timer ......................... •

Electronic Controls & Sensors . ON OFF

Evaporator Sensor ....................... •

Condenser Sensor ....................... •

Ice Level Control .......................... •

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Freeze Cycle

NOTE. Before charging the refrigerant system

always check the type of refrigerant and quantity as specified on the individual ice machine dataplate. The refrigerant charges indicated are related to average operating conditions.

COMPONENTS DESCRIPTION

A. EVAPORATOR TEMPERATURE

SENSOR

The evaporator temperature sensor probe, located in contact with the evaporator serpentine, detects the dropping of the evaporator temperature during the freezing cycle and signals it by supplying a current flow to the micro processor of P.C. BOARD. According to the current received, the evaporator sensor supplies power to the P.C. BOARD first, when it reachs 0°C (32° F), second at -15°C (5°F); in this second case it supply power to the electronic timer built into the P.C. BOARD so that it may take control of the fength of the 2nd phase of freezing cycle. The length of the timed phase is pre-f ixed by the setting of the keys 1, 2, 3 and 4 of the DIP SWITCH.

The activation of the electronic timer (-15°C 5°F) is monitored by the lighting up of the RED LED placed in the front of the P.C. BOARD. This lighting up occures usually in the mid period of the freezing cycle and signals the switching from the first to the second phase of the freezing cycle.

NOTE. Whenever, after 15 minutes from the beginning of the freezing cycle, the evaporating temperature have not yet reached the value of 0°C (32°F), the P.C. BOARD switches OFF the machine with the BLINKING of RED LED.

B. CONDENSER TEMPERATURE

SENSOR

The condenser temperature sensor probe, located within the condenser fins (air cooled version) or in contact with the tube coil (water cooled version) detects the condenser temperature variations and signals them by supplying current, at low voltage, to the P.C. BOARD. In the air cooled versions, in relation to the different current received, the micro processor of the P.C. BOARD supplies, through a TRIAC, the power at high voltage to the fan motor so to cool the condenser and to reduce its temperature.

MODEL VOLTAGE CUBE SIZE

discharge

MXG 327 A 230/50/1 M 145 2,8 / 1 10 - 13,5

MXG 327 W 230/50/1 M

MXG 427-437 A 230/50/1 M 150 1,9 / 0,7 10 - 12

MXG 427-437 W 230/50/1 M

OPERATING PRESSURE

(bar)

at 21°C amb. / 15°C water

suction

(beg./end freez.)

REF. CHARGE

(R290 - gr.)

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In case the condenser temperature rises and reaches 70°C (1 60°F) - on air cooled models - or 62°C (145°F) - on water cooled models - the current

arriving to the micro processor is such to

cause an

immediate and total stop of the machine

operation.

C. ICE BIN LEVEL LIGHT CONTROL

The electronic ice bin level control, located into the storage bin, has the function to stop the operation of the ice machine ONLY AT THE END OF THE HARVEST CYCLE when the light beam is interrupted by the ice cubes stored into the bin. When the light beam is interrupted the Bin Full YELLOW LED starts blinking

SETTING OF THE ICE LEVEL CONTROL SENSIVITY

In case of any need it's possible to up to date calibrate the sensivity of the optical ice level control just by turn OFF and ON the Power supply by main switch.

NOTE. The setting of the Ice Level Control Sensivity must be done any time a new PC Board or a new lce Level Control is installed in the machine.

D. P.C. BOARD (Data processor)

The P.C. BOARD, fitted in its plastic box located in the front of the unit, consists of two separated printed circuits one at high and the other at low voltage integrated with fuse on power out (6.3 A), of four aligned LEDS monitoring the operation of the machine, of one extra monitoring RED LED (blink 0°C - steady - 15°C), of one DIP SWITCH with ten keys, of one push button, of input terminals for the leads of the sensor probes and input and output terminals for the leads of the ice maker electrical wires. The P.C. BOARD is the brain of the system and it elaborates, through its micro processor, the signals received from the three sensors in order to control the operation of the different electrical components of the ice maker (compressor, water pump, solenoid valves, etc.).

SYEN

CONDENSER

SENSOR

EVAPORATOR

SENSOR

PUSH BUTTON

0¡C-BLINKING

-13¡C-STEADY

TERMINAL BOARD

FUSE

COMPRESSOR RELAY

TRIAC

TRANSFORMER

VARISTOR

WATER PUMP RELAY

HOT GAS, WATER INLET AND

PURGE VALVES RELAY

ALARM

BIN FULL

POWER

EVAPORATOR SENSOR

CONDENSER SENSOR

OPTICAL ICE LEVEL CONTROL SENSOR

WATER LEVEL SENSOR

EC SERIES ONLY

EXTERNAL

SWICHES

SOCKET

COMPRESSOR ELECTRICAL CONNECTIONS

WATER DRAIN PUMP RELAY EC SERIES ONLY

JUMP OUT - EC SERIES

JUMP IN Ð AC SERIES

WATER SYSTEM

CLEANING REMIND

JUMP OUT - 12 MONTHS

JUMP IN Ð NO REMIND

START UPDELAY TIME JUMP OUT Ð 60Õ DELAY JUMP IN - NO DELAY

TEST

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At restart, from any tripping OFF at Bin Full, the new PC Board assures 45 seconds water filling phase so to refill the water sump up to the maximum level. In case of malfunction of the Optical Ice Level Control, thenew PC Board switch ON alternativelt the Yellow and Red Led continuously.

On the PC Board there are four jumpers to select:

• "no remind" or 12 months remind time for the water system cleaning

• Operation of the Purge Out Water Pump (Jump IN on EC series)

• "no delay" or 60 minutes delay time at first start up

• TEST

In case the TEST contacts are closed with the Jumper, at the Start Up of the machine the PC Board energizes all the electrical components for maximum 3 minutes time. At the end of the 3 minutes the PC Board switch OFF the entire machine with the blinking of all the LED's as shown on the bottom drawing.

E. PUSH BUTTON OPERATION

DURING WATER FILLING PHASE

• Push for more then 2” but less then 5” the

machine enters in Cleaning Mode

• Push for more then 5” the machine by-pass the

Water Filling Phase

DURING FREEZING/HARVEST CYCLE

• Push for more then 5” during the Freezing

cycle the machine goes immediately into Harvest

• Push for more then 5” during the Harvest cycle

the machine enters immediately in the Freezing cycle

SYEN

CONDENSER

SENSOR

EVAPORATOR

SENSOR

ON STEADY

BLINKING

JUMP OUT - EC SERIES

JUMP IN Ð AC SERIES

WATER SYSTEM

CLEANINGREMIND

JUMP OUT - 12 MONTHS

JUMP IN Ð NO REMIND

START UPDELAY TIME JUMP OUT Ð 60Õ DELAY JUMP IN - NO DELAY

TEST

The length of Harvest is equal to:

•35” if Push Button is activated before 15°C evaporating temperature LED activation

•As per Harvest cycle chart, if Push Button is activated after -15°C evaporating temperature LED activation (Red LED inside PC Board ON steady)

F. LED MEANING

GREEN LED ON

Unit under power

YELLOW BIN FULL LED ON

Unit shut-OFF at storage bin full

YELLOW BIN FULL LED BLINKING

Infrared beam break out

RED ALARM LED ON

Too hi condensing temperature

RED ALARM LED BLINKING

Too hi evaporating temperature

YELLOW FREEZING CYCLE ON

Unit in freezing cycle mode

YELLOW FREEZING LED AND RED ALARM LED ON

Condenser sensor out of order

YELLOW FREEZING LED AND RED ALARM LED BLINKING

Evaporator sensor out of order

FREEZING CYCLE

BIN FULL

POWER

TOO HI EVAP TEMP

TOO HI COND TEMP

PUSH BUTTON

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LED STATUS

REASON WHY

ON STEADY UNIT UNDER POWER

ON STEADY FREEZING CYCLE

BLINKING

60 MINUTES DELA Y AT START UP JUMPER J3 OUT

ON STEADY

TOO HI DISCHARGE PRESSURE/TEMP

BLINKING

TOO HI EVAP. TEMP. (> 0C°) AFTER 15’ FROM START UP

ON STEADY UNIT OFF AT BIN FULL

BLINKING

SLOW

I/R BEAM CUTTED

I/R ON AFTER TRIP OFF AT BIN FULL

BLINKING

FAST

ON STEADY I/R CALIBRATION DONE

BLINKING

UNIT IN CLEANING MODE OR TRIPPING OFF AFTER TEST - JUMPER TEST IN

ON STEADY

CONDENSER SENSOR OUT OF ORDER

BLINKING

EVAPORATOR SENSOR OUT OF ORDER

BLINKING

ALTERNATIVELY

I/R SENSOR OUT OF ORDER

PUSH

PUSH > 5” DURING WATER FILLING TO

MOVE THE UNIT INTO FREEZING

PUSH > 5” DURING FREEZING

TO MOVE THE UNIT INTO DEFROST

PUSH > 5” DURING DEFROST

TO MOVE THE UNIT INTO FREEZING

PUSH 2” > 5” DURING WATER FILLING

TO MOVE THE UNIT INTO CLEANING

PUSH DURING THE 60 MIN START UP

DELAY TIME TO BY-PASS IT

G. DIP SWITCH

The P.C.BOARD which controls the entire operation of the ice maker, has a DIP SWITCH with ten switching keys which allow to set up the micro processor program in order to extend or to shorten the length of freezing cycle in relation to the different model and versions of ice machines.

The DIP SWITCH first four keys setting

determines the length of the 2nd phase of freezing cycle (controlled by the electronic timer) as detailed in the table B.

The DIP SWITCH keys 5 & 6 setting determines the length of the defrost cycle according to the size of the cubes (Large or Medium) as per the following setting:

ON ON : PROGRAM A ON OFF : PROGRAM B OFF OFF : PROGRAM C OFF ON : PROGRAM D

LENGTH OF HARVEST CYCLE

ACCORDING TO THE TIME TO DROP THE

EVAP. TEMPERATURE FROM 0°C TO -15°C

LENGTH PROGRAMS

HARVEST

CYCLE

ABC D

180” Up to 6’30” *** Up to 9’30” xxxx 165” 6’30”-7’ Up to 3’ 9’30”-10’ xxxx 150” 7’-8’ 3’-3’15’ 10’-11’ xxxx 135” 8’-9’ 3’15”-3’30” 11’-12’ xxxx 120” 9’-10’30” 3’30”-4’30” 12’-13’30” < 3' 105” 10’30”-12’ 4’30”-6’ 13’30”-15’ 3' - 4'

90” >12’ >6’ >15’ > 4'

The DIP SWITCH N° 7 and 8 allow the extention of the length of the harvest/defrost cycle according to their combination as per following chart:

DIP SWITCH ADDITIONAL DEFROST TIME

ON ON 0

OFF ON 30"

ON OFF 60"

OFF OFF WATER PUMP OFF

LENGTH OF TIMED PORTION OF FREEZING CYCLE ACCORDING TO THE

DIP SWITCH SETTING COMBINATIONS

TAB. B

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The 9th key is used to supply power to the water pump for the first 15 seconds of the defrost cycle

- position OFF - or for the first 30 seconds -

position ON. The 10th key is used to modify the CUT-OUT

condensing temperature from 70°C (160°F) for the air cooled versions - ON position - to 60°C (140°F) - OFF position - for the water cooled versions.

H. WATER SPRAY SYSTEM

Through its nozzles, the water pumped, is sprayed in each individual cup to be frozen into ice. It consists of one spray tube wheve are located several spray nozzles.

I. WATER PUMP

The water pump operates continually throughout the freezing cycle and on the first 15 or 30 seconds of the defrost cycle so to such the remaining water from the sump tank (reach in mineral salts) and drain it out. During the freezing cycle the pump primes the water from the sump to the spray system and through the spray nozzles sprays it into the

inverted cup molds to be frozen into crystal clear ice cubes. It is recommended that the pump motor bearings be checked at least every six months.

J. WATER INLET SOLENOID VALVE -

3/4 GAS MALE FITTING

The water inlet solenoid valve is activated by the micro processor of the P.C. BOARD during the first 5 minutes of water filling phase and as well during the defrost cycle. When energized it allows a metered amount of incoming water to flow overt he evaporator cavity to assist the hot gas in defrosting the ice cubes. The water running over the evaporator cavity drops by gravity, through the dribbler holes of the platen, into the sump reservoir where it will be sucked by the water pump and primed to the spray system.

K. HOT GAS SOLENOID VALVE

The hot gas solenoid valve consists basically in two parts: the valve body and the valve coil.

Located on the hot gas line, this valve is energized through the micro processor of P.C. BOARD during the defrost cycle and as well during the water filling phase. During the defrost cycle the hot gas valve coil is activated so to attract the hot gas valve piston in order to give way to the hot gas discharged from the compressor to flow directly into the evaporator serpentine to defrost the formed ice cubes.

L. FAN MOTOR (Air cooled version)

The fan motor is controlled through the P.C. BOARD and the TRIAC by the condenser temperature sensor. Normally it operates only during the freezing cycle to draw cooling air through the condenser fins. In the second part of the freezing cycle, the fan motor can run at intermittance as the condenser pressure must be kept between two corresponding head pressure values (16÷18 bars- 225÷250 psig).

M. COMPRESSOR

The hermetic compressor is the heart of the refrigerant system and it is used to circulate and retrieve the refrigerant throughout the entire system. It compresses the low pressure refrigerant vapor causing its temperature to rise and become high pressure hot vapor which is then released through the discharge valve.

N. WATER DRAIN SOLENOID VALVE

The water drain solenoid valve, electrically connected in parallel to the water inlet and to the hot gas solenoid valves, is energized for all the length of the defrost cycle. By means of the water pump, that remains energized for 30 seconds at the beginning of the defrost cycle, it allows the drain out of all remaining water (rich of minerals deposited during the previous freezing cycle) from the sump tank. By doing so it allows to the ice maker to make every new freezing cycle with new fresh water, avoiding thereby the accumulation of sediments and scales, which soon or later will cause the partial or total clogging of the water system on the unit.

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ADJUSTMENT, REMOVAL AND REPLACEMENT

PROCEDURES

SMALL IDENTATION

LITTLE OR NO ICE IN CENTER OF CUBES

THICK BULGE SOLID ICE

OVER SIZE

NORMAL SIZE-SHAPE

SHALLOW SIZE

ADJUSTMENT OF THE CUBE SIZE

CAUTION. Before performing actual adjustment of the cube size, check other possible causes for cube size problems, refer to the Service Diagnosis Section for problem review and analysis. Do not perform any adjustment till the icemaking system has progressed through severaÏ complete freezing and harvest cycle, to observe size and quality of ice cubes and whether or not the cube size problem exists.

I. lf the cubes are shallow size (Indentation is

too deep) probably the length of the second phase of the freezing cycle is too short so, to extend such length you have to:

1. Locate the DIP SWITCH on the front of the P.C. Board.

2. Take note of thecombination of the first four DIP SWITCH KEYS and check the corrisponding length of freezing cycle 2nd phase on Table B.

3. Change the same DIP SWITCH KEYS setting so that it will correspond to the combination on table B pre-ceding the one remarked at step 2. This will allow an extension of the freezing cycle of two more minutes.

4. Observe the ice cubes in the next two harvests and eventually repeat steps 2 and 3 above until proper ice cubes size is achieved. See figure.

II. lf the cubes are oversize size (Indentation is too full) probably the length of the second phase of the freezing cycle is too long. To shorten such length you have to:

1 . Locate the DIP SWITCH on the front of the P.C. Board.

2. Take note of the combination of the first four DIP SWITCH KEYS and check the corrisponding length of freezing cycle 2nd phase on Table B.

3. Change the same DIP SWITCH KEYS setting so that it will correspond to the combination on table B coming next to the one remarked at step 2. This will reduce an the freezing cycle length of two minutes.

4. Observe the ice cubes in the next two harvests and eventually repeat steps 2 and 3 above until proper ice cubes size is achieved. See figure.

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WIRING DIAGRAM

MXG 327 - 427 - 437 A 230/50/1

Page 30

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Page 31

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SERVICE DIAGNOSIS

SYMPTOM POSSIBLE CAUSE SUGGESTED CORRECTION

Unit will not run Blown power in fuse in P.C.Board Replace fuse & check for cause of (No warning LEDS glows) blown fuse

Main switch in OFF position Turn switch to ON position Inoperative P.C.Board Replace P.C.Board Loose electrical connections Check wiring

(Green LED-Power ON glows)

Blown power out fuse in P.C. Board

Replace fuse & check for cause of blown fuse

(Bin full LED glows) Inoperative ice level control Clean or replace ice level control

Inoperative P.C.Board Replace P.C.Board

(Red-alarm LED glows) High head pressure Dirty condenser. Clean

Inoperative fan motor. Replace Shortage of water (WC)

(Red-alarm LED blinks) High evaporating temperature Hot gas valve leak - Replace it.

after 15 mins. beginning freeze Water inlet valve leak - Replace it.

Short of refrigerant. Compressor cycles intermittently

(Freezing or Bin Full LED + Condenser sensor out of order Replace it Red-alarm LED glow)

(Freezing or Bin Full LED + Evaporator sensor out of order Replace it Red-alarm LED blink)

(Freezing or Bin Full LED + Ice Level Control out of order Replace it Red-alarm LED blink alternatively)

Compressor cycles intermittently Low voltage Check circuit for overloading

Check voltage at the supply to the

building. If low, contact the power company Contactor with burnt contacts Replace it Non-condensable gas in system Purge the system Compressor starting device with Check for loose wires in starting

loose wires device Mechanical problem Replace compressor

Cubes too small Freezing cycle too short Review setting of DIP SWITCH keys

Capillary tube partially restricted

Blow charge, add new gas & drier, after

evacuating systemwithvacuum pump Moisture in the system Same as above Shortage of refrigerant Check for leaks & recharge

Cloudy cubes Shortage of water See remedies for shortage of water

Dirty water supply Use water softner or water filter Accumulated impurities

Use SCOTSMAN Ice Machine cleaner

Shortage of water Water spilling out through curtain Check or replace curtain

Water solenoid valve not opening Replace valve Water leak in sump area Locate and repair Water flow control plugged Replace water inlet valve Leak of water drain valve Replace valve

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SYMPTON POSSIBLE CAUSE SUGGESTED CORRECTION

Irregular cubes size & some Some jets plugged Remove spray bar & jet bearing cloudy and clean them

Shortage of water See shortage of water Unit not level Level as required Spray bar not rotating Remove spray bar & jet bearing

and clean them

Cubes too large Freezing cycle too long

Review setting of DIP SWITCH keys

Inoperative evaporator sensor Replace sensor

Decreased ice capacity Inefficient compressor Replace

Leaky water valve Repair or replace Non-condensable gas in system Purge the system Poor air circulation or excessive Relocate the unit or provide for

hot location (Red-alarm LED glows

) more ventilation

Overcharge of refrigerant

Correct the charge. Purge off slowly

Capillary tube partially restricted Blow charge, add new gas & drier,

after evacuating system with

vacuum pump Hot gas solenoid valve leaking Replace valve Short of refrigerant Charge to data plate indication

Discharge head pressure too high See incorrect discharge pressure

Poor harvest Restriction in incoming water line

Check water valve strainer and flow

control. If necessary enlarge the

flow control orifice Water inlet valve not opening Valve coil with open winding

Replace valve Hot gas valve orifice restricted Replace hot gas valve assy Clogged air vented holes in mold cups

Clean out holes plugged Discharge head pressure too low See incorrect discharge pressure

Unit won’t harvest Inoperative P.C.Board Replace P.C.Board

Hot gas valve not opening Valve coil with open winding

Replace valve Water solenoid valve not opening Valve coil with open winding

Replace valve

Incorrect discharge pressure Inoperative condenser sensor Replace sensor

Inoperative P.C.Board Replace P.C.Board Water regulating valve misadjusted

Adjust its setting stem

Excessive water in unit base Water tubing leaking Check. Tighten or replace

SERVICE DIAGNOSIS

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MAINTENANCE AND CLEANING INSTRUCTIONS

A. GENERAL

The periods and the procedures for maintenance and cleaning are given as guides and are not to be construed as absolute or invariable. Cleaning, especially, will vary depending upon local water and ambient conditions and the ice volume produced; and, each icemaker must be maintened individually, in accordance with its particular location requirements.

B. ICEMAKER

The following maintenance should be scheduled at least two times per year on these icemakers.

1 . Check and clean the water line strainer.

2. Check that the icemaker is levelled in side to side and in front to rear directions.

3. Clean the water system, evaporators, bin and spray bar/s using a solution of SCOTSMAN Ice Machine Cleaner. Refer to procedure C cleaning instructions and after cleaning will indicate frequency and procedure to be followed in local areas.

4. Reach the water spray bar from the inside of the freezing chamber lifting it from its seat with its bottom race washer.

Dip it into a tray filled with cleaning solution then rinse it under a tap water stream.

With a pick clean the orifice of the water stream jet that propells the spray bar.

NOTE. Cleaning requirements vary according to the local water conditions and individual user operation. Continuous check of the clarity of ice cubes and visual inspection of the water spraying parts before and after cleaning will indicate frequency and procedure to be followed in local areas.

5. With the ice machine and fan motor OFF on air cooled models, clean condenser using vacuum cleaner, whisk broom or non metallic brush taking care to do not damage both the condenser and ambient temperature sensor probes.

6. Check for water leaks and tighten drain line connections. Pour water down through the storage bin drain line to be sure that drain line is open and clear.

7. Check size, condition and texture of ice cubes. Perform adjustment of DIP SWITCH keys as required.

8. Check the ice level control sensor to test shut-off. Put some ice cubes between the light source and the receiver so to cut off the light beam for at least one minutes. This should cause the ice maker to shut off and the light-up of the 2nd LED (yellow light).

IMPORTANT. Perform the above check only at the end of harvest cycle or at the beginning of freezing cycle in order to do not cause to the unit to make a double freezing cycle.

NOTE. Within few seconds after the removal of the ice cubes from the Infrared sensing light the icemaker restarts in freezing cycle. The ice level control uses devices that sense light, therefore they must be kept clean enough so they can "see". Every month clean/wipe the sensing "eyes" with a clean soft cloth.

9. Check for refrigerant leaks.

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C. CLEANING INSTRUCTIONS OF

WATER SYSTEM

1. Remove left, center and right front panels to gain access either to the control box and to the evaporator.

2. Wait till the end of defrost cycle then turn the unit OFF by the main switch (disconnect power supply).

3. Prepare for each freezing chamber the cleaning solution by diluting in a plastic container two or three liters of warm water (45°-50°C) with a 0,2-0,3 liters of SCOTSMAN Ice Machine Cleaner.

WARNING. The SCOTSMAN Ice Machine Cleaner contains Phosphoric and 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 immediatelly. In case of external contact flush with water. KEEP OUT OF THE REACH OF CHILDREN

4. Scoop out all the ice cubes stored into the bin in order to prevent them from being contaminated with the cleaning solution then flush out the water from the sump reservoir by bending down the vertical sump drain hose.

5. Remove the evaporator cover then slowly pour onto the evaporator piaten the cleaning solution- With the help of a brush dissolve the most resistant and remote scale deposits in the platen. Perform the same for all the four evaporators.

6. Give power to the unit by the main switch.

7. During the Water Filling Phase push RESET BUTTON for more then 2” but less then 5” the machine enter in Cleaning Mode (Fig.7)

Rx Tx

WATER IN VALVE

HOT GAS VALVE

CONTACTOR COIL

FAN MOTOR

WATER PUMP

- EVAPORATOR

- AMBIENT

- CONDENSER

TEMPERATURE SENSORSBINCOMPRESSOR

TRANSF.

DATA

PROCESSOR

ELECTR.

TIMER

DIP SWITCH

ELECTRONIC CARD

RELAYS

RELAY

TRIAC

WATER DRAIN VALVE

FIG. 7

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FIG. 8

8. With the system in Cleaning mode the water pump is the only component in operation to circulate the cleaning solution in the entire water system

9. Let the unit remain in the cleaning mode for about 20 minutes then turn the main switch to OFF (disconnect unit from POWER)

10. Flush out the cleaning solution from the sump reservoirs then pour onto each evaporator cavity two or three liters of clean potable water with a capfull of antibacteria solution to rinse and sanitize the mold cups and the platen. If necessary remove the water spry bar to clean it separately as per steps 3 and 4 of paragraph B.

11. Give power to the unit by the main switch

12. During the Water Filling Phase push RESET BUTTON for more then 2” but less then 5” the machine enter in Rinsing Mode (Fig.7)

13. Let the unit remain in the RINSING MODE mode for about 10 minutes then turn the main switch to OFF (disconnect unit from POWER)

14. Flush out the rinsing solution from the sump reservoirs

15. Place again the evaporator cover and the unit service panels.

16. Give POWER to the unit.

17. At completion of the freezing and harvest cycle make sure of proper texture and clearness of the ice cubes and that, they do not have any acid taste.

ATTENTION. in case the ice cubes are cloudy, white and have an acid taste, melt them immediatelly by pouring on them some warm water. This to prevent that somebody could use them.

18. Wipe clean and rinse the inner surfaces of the storage bin.

REMEMBER. To prevent the accumulation of undesirable bacteria it is necessary to sanitize the interior of the storage bin with an anti-algae disinfectant solution every week.

Rx Tx

WATER IN VALVE

HOT GAS VALVE

FAN MOTOR

WATER PUMP

- EVAPORATOR

- AMBIENT

- CONDENSER

TEMPERATURE SENSORSBINCOMPRESSOR

TRANSF.

DATA

PROCESSOR

ELECTR.

TIMER

DIP SWITCH

ELECTRONIC CARD

RELAYS

RELAY

TRIAC

WATER DRAIN VALVE

CONTACTOR COIL

FIG. 8

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Sanitation

NOTE. Sanitation of the water system is

recommended to be done once a month.

19. Prepare in a plastic container the sanitation solution as per manufacturer dilution using warm water (45-50 °C).

NOTE. Never mix the cleaning with the sanitising solution.

20. Follow the procedures as per cleaning (from item 10 to item 13) just shorting the operation of the water pump to 10 minutes.

21. Place again the evaporator cover and the unit service panels.

22. At completion of the freezing and harvest cycle make sure of proper texture and clearness of the ice cubes and that, they do not have any acid taste.

ATTENTION. In case the ice cubes are cloudy-white and have an acid taste, melt them immediately by pouring on them some warm water. This to prevent that somebody could use them.

23. Wipe clean and rinse the inner surfaces of the storage bin.

REMEMBER.

To prevent the accumulation of undesirable bacteria it is necessary to sanitize every week the interior of the storage bin.