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IM SERVICE TRAININGFeaturing theIM-51BAE

80041 9/9/99

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All IM models have similar sequence of operation. This manual is designed as ageneric IM Training manual.

The Hoshizaki IM series ice machineuses a horizontal evaporator design.This compact unit is designed forcounter-top, under-counter, or free-standing installations.

A standard 120 volt power cordprovides the electrical connection.The unit is designed to operate on aseparate 15 amp circuit.

The water supply connection is½”FIP and is located at the bottomright rear of the unit. A minimum3/8” water line is required for properoperation.

The drain connection is ¾”MIP andis located on the left rear of the unit.Since the unit will likely be enclosed,it is recommended to use flexiblesupply and drain connections. Thiswill allow easy removal if service isnecessary.Access to the evaporatorcompartment is gained by removingthe front and top covers.

Open the bin door and remove thefront cover screws and drain panthumbscrews. Lower the drain panpipe into the drain hole.

Lift upward on the front panel andpush backward to remove the topcover.

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This horizontal evaporator and waterdistribution system is unique to theIM series.

The ABS water plate sprays water upinto the evaporator cells to form thesquare IM cube.

The moveable water pan assemblyincludes the water plate, reservoirpan, and pump motor assembly.

Tension springs connect two camarms to the water plate assembly. Anactuator motor rotates the cam armsto raise and lower the water panduring the ice making cycle.

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The front cam arm has a switch leverthat operates the actuator toggleswitch located above the panassembly.

The actuator toggle switch controlsthe direction of rotation for theactuator motor and energizes thepump motor during the freeze cycle.• When the switch is in the right

position, the actuator motorrotates counter clock wise tolower the water pan assembly.

• When the switch is in the leftposition, the actuator motor turnsclock wise to raise the water panassembly.

The IM51 uses a mechanicalproximity switch bin controlassembly located in the bin area.

When ice fills the bin and pushes thecontrol arm over, the activatormagnet moves to the switch andcloses the contacts.

The IM bin control closes thecontacts to signal the control boardto shut down the unit. This isdifferent from the standard KMcontrol, which opens the contacts tode-energize the unit.

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The louver has a flip down cover toaccess the control switch.

The switch has 3 positions.

ICE, OFF, & WASH.

The louver covers the compressorcompartment. Remove the louverscrews and lift the louver forward toaccess the condenser coil fanassembly and compressor.

For easy access during preventativemaintenance or service, the inletwater valve is located in the frontright hand corner of the compressorcompartment.

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The control box is accessed from therear of the unit. Remove the screwsholding the pipe cover and thecontrol box cover to reach thecontrol board and other components.

A solid state board controls the IMoperation. Several adjustments areincluded on the board. Theseadjustments are factory set for properoperation.

Later, we will cover the adjustmentsand discuss the proper settings.

Now, lets take a look at the basic IMsequence of operation. When thecontrol switch is placed in ICE, theunit starts in the Initial Harvest cycle.

When power is supplied, thecompressor, hot gas valve, andactuator motor energize. Thecompressor starts in harvest toreduce the starting load and increasecompressor life. This will also clearany ice from the evaporator platebefore the freeze cycle begins.

CONTROL SWITCH TO ICE.

INITIAL HARVEST CYCLE.

FREEZE CYCLE.

NORMAL HARVEST CYCLE.

FREEZE, HARVEST, FREEZE, HARVEST, FREEZE, HARVEST,

“ “

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The actuator motor turns counterclock wise to rotate the cam armsand lower the water pan away fromthe evaporator. When the water plateis completely down the switch levermoves the actuator toggle switch tothe left. The board energizes theinlet water valve and condenser fanmotor and de-energizes the hot gasvalve.

Switching the actuator toggle switchto the left position also reverses theactuator motor. The motor now turnsclock wise to raise the water plateupward.

When the plate reaches theevaporator, the cam arm switch levermoves the actuator toggle switch tothe right position. This stops theactuator motor and sets up the circuitto lower the plate in the next harvestcycle. It also energizes the pumpmotor and the board de-energizes theinlet water valve. The Freeze Cyclenow begins.

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The freeze cycle is controlled by athermistor, which is mounted at theevaporator outlet. The pump isspraying water up into the evaporatorcells to form the square IM cubes.The evaporator temperature lowersas the ice cubes form.

A thermistor temperature of –9.4°Fsignals the control board to beginharvest and energize the hot gasvalve and actuator motor circuit. Theactuator motor now turns counterclock wise to lower the water pan.The switch lever moves the actuatortoggle switch to the left. This sets theactuator motor circuit to raise thewater plate at the end of harvest. Theboard energizes the inlet water valve.

Unlike the initial harvest, the normalharvest is controlled by thethermistor. When the thermistorreaches 59°F, the control board de-energizes the hot gas valve andenergizes the condenser fan motor.The actuator motor energizes to raisethe plate. When the plate reaches theevaporator, the actuator toggleswitch is moved back to the right.The board de-energizes the inletwater valve and the freeze cyclebegins again. The average harvestcycle is about 3 minutes.

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The unit will continue through thefreeze and harvest cycle until the bincontrol shuts down the refrigerationsystem.

When pushed over, the bin controlhas a 10-second delay before shutdown occurs. An 85-second delayoccurs at startup when the bincontrol is released.

Now let’s take a look at the controlboard adjustments. Remember thatthe adjustments are factory set toprovide proper operation in normaloperating conditions.

NO SEASONAL ADJUSTMENTS!

The board adjustments are madethrough variable resistors on theboard. The cube control is markedVR5. This adjusts the thermistorswitching temperature of - 9.4°F andthe length of the freeze cycle. Thedimple size in the cube also changes.Adjusting to a larger dimple willresult in a shorter freeze cycle and asmaller cube. A smaller dimplesetting will result in a longer cycleand a larger cube. The factorysetting is 5.

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The maximum freeze timer is VR3.This timer will automatically switchthe unit to the harvest cycle if thefreeze cycle last longer than thesetting time. The factory setting is45 minutes.

The defrost control VR2 will adjustthe time period between ice-drop andactuator motor restart during harvest.The factory setting is 4. This settingrepresents approximately 40 seconds.VR2 would be adjusted longer if theunit is operating in a cooler ambienttemperature.

The control board includes a push-button reset. Pressing this buttonwill initiate a harvest cycle anytimethe control switch is in ICE position.

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A red Service Indicator LED is alsoincluded on the control board. ThisLED will either light continually orflash to indicate a service fault. Afault diagnosis chart in the servicemanual will help the techniciandetermine the actual problem.

See chart next page.

Preventative maintenance for the IMis simple. Follow these steps to allowthe unit to operate efficiently.1. Clean the mesh air filter twice

monthly to ensure good airflow.2. Clean the condenser once a year

using a brush or vacuum.3. Check and clean the inlet water

valve screen as needed to assureproper water flow.

4. Clean and sanitize the waterdistribution system annually usingthe recommended cleaner.

5. Wipe down the exterior using asoft cloth and neutral cleaner.

Cleaning tips:• A detailed cleaning label is

located under the top cover. Moredetailed instructions are includedin the customers InstructionManual or in the product ServiceManual.

• Always follow the cleaninginstructions and use therecommended ice machinecleaner.

• Use the cleaning brush shippedwith the unit to clean tight places.

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FAULT DIAGNOSIS

Check the status of the Service lamp on the Controller Board (LED-5) by removing theControl Box Cover.

Lamp ON – Water Plate closedThis tends to indicate the Back-up Timer has stopped machine operation during thefreeze cycle. High ambient and water temperature are an obvious cause. But checkout each component that could result in an extended freezing time (See guide below).

Lamp ON – Water Plate openThe Timer has stopped the machine because if an excessive defrost time. See theguide below to check out the probable cause.

Lamp flashing ON/OFFIf on the first cycle, check out the Cam operation and/or Toggle Switch. If the machinehas been in service for some time, the Controller Board may be at fault.

REMEMBER: Hoshizaki controllers are very reliable. They also control every component’s Operation. So if a component malfunctions, the controller will respond.

Do not replace controllers in an attempt to shorten the diagnosis process andnot before carefully checking the actual fault and possible cause.

When the icemaker stops, the Controller Board Interlock indicator shows possible faults.

PATTERN INTERLOCKINDICATOR

WATER TANK POSITION

POSSIBLE CAUSE REMEDY

1

2

3

1.

4

OnlyFirstCycle

ActuatorToggle SwitchLever bent

ReplaceActuatorToggleSwitch

Replace

Replace

Replace

Can Arm (A) Broken

DefectiveActuator Motor

DefectiveController Board

O

Cam Arm

Flashing

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PATTERN INTERLOCKINDICATOR

WATER TANK POSITION

POSSIBLE CAUSE REMEDY

1

2 0V

Leak

3

Hot Gas leak

4

5 Gas

2

6

1

115v

2 Gas

3

3

1 Lever

2

3

4Actuatormotor Pin

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5

Freeze Cycle

Clogged Air Filterand/or Condenser

Clean orReplace

Replace

Replace

Checkfor leak

ReplaceComp. StartCapacitor

Replace

Water leak fromWater SolenoidValve

Gas leak from HotGas SolenoidValve

Fan Motorstopped

Gas leak

Compressorstopped

Hot Gas SolenoidValve closed andwill not open

Replace

Gas leak Checkfor leak

Compressorstopped

ReplaceComp. StartCapacitor

Replace

Replace

ReplaceActuatorToggle Swt.

ActuatorToggle SwitchLever bent

Can Arm (A) Broken

Cam Pindamaged

ReplaceCam Pinand CamArm (A)

Defective CubeControl Thermistor

Replace

HarvestCycle

OR

Defective ActuatorMotor

Cam Arm

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WIRING DIAGRAMIM-51BAE

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IM SERIES REVIEW QUIZChoose the best answer for each question below.

1. The IM control board is located in the rear or the unit. True False

2. The IM unit uses a thermostatic bin control.True False

3. The bin control switch must OPEN or Close to shut the unit down.

4. The IM series uses R-404A or R-134A refrigerant.

5. To raise the water pan assembly the actuator toggle switch must be in the RIGHT or LEFT position.

6. With the actuator toggle switch in the left position, the actuator motor turns CLOCKWISE or COUNTER CLOCKWISE.

7. Adjusting the cube control or dimple adjustment changes which temperaturesetting? - 9.4ºF or 59ºF.

8. The maximum freeze timer on the control board is factory set at 60 MINUTES or 45 MINUTES.

9. The black push button reset is included on the control board forHARVEST INITIATION or SAFETY RESET.

10. The control transformer used in the IM series units is a 12VOLT or 24 VOLT output.

NOTE: Quiz answers are at the bottom of next page.

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NOTES:

Quiz answers:1.True, 2. False, 3. Close, 4. R-134A , 5. Left , 6. CW , 7. – 9.4ºF, 8. 45 min., 9. Harvest initiation, 10. 24 volt