Hoshizaki KM-470AJ Service Manual Download Page 30

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2. Harvest Timer (S4 dip switch 1 & 2)

The harvest timer starts counting when the thermistor reaches 9°C at the evaporator

outlet and the control board reads 3.9 kΩ from the thermistor. The harvest timer is

factory set, and generally no adjustment is required. However, a setting longer than the

factory setting may be advised in cases where the drain provided at harvest needs to be

prolonged for extra cleaning. Before changing this setting, contact Hoshizaki Technical

Support at 1-800-233-1940 for recommendations. Keep in mind that setting the harvest

timer to a longer setting decreases 24-hour production.

Note that the pump-out timer (S4 dip switch 3 & 4) acts in place of the harvest timer

during cycles with a pump out. For details, see "III.C.3. Pump-Out Timer (S4 dip switch

3 & 4)."

Note: On models with a pump-out every cycle, the harvest timer is only relevant during

the initial harvest cycle since a pump out occurs every cycle thereafter.

S4 Dip Switch Setting

Time

(sec.)

No. 1

No. 2

OFF

120

180

3. Pump-Out Timer/Harvest Time During Pump-Out (S4 dip switch 3 & 4)

NOTICE

• On models with harvest pump timer, do not adjust 3 off and 4 on. Pump

does not run in pump-out rotation in this setting.

When a pump-out is called for, the pump motor stops for 2 sec., then energizes in the

reverse direction, taking water from the bottom of the water tank and forcing pressure

against the check valve seat allowing water to go through the check valve and down

the drain. At the same time, water flows through the small tube to power flush the float

switch. The pump motor drains the water tank for the time determined by the pump-out

timer. The pump-out timer also acts in place of the harvest timer during cycles with a

pump-out. The pump-out timer is factory set, and generally no adjustment is required.

However, where water quality is bad and the icemaker needs a longer pump-out time,

the pump-out timer can be adjusted. The pump-out timer control can be set to pump-out

for 10 or 20 sec.

S4 Dip Switch Setting

Time (sec.)

Inlet Water

Valve

No. 3

No. 4

S5-4 OFF S5-4 ON

S5-4 OFF

S5-4 ON

OFF

150

100

Closed

OFF

180

130

Closed

OFF

120

Open

Closed

180

Closed

T1: Time to drain the water tank

T2: Harvest timer at pump out

Summary of Contents for KM-470AJ

Page 1: ...MODULAR CRESCENT CUBER SERVICE MANUAL KM 470AJ F136 1056 042020 ...

Page 2: ...ump Time Harvest Assist Duration S4 dip switch 6 31 6 Harvest Pump Time Harvest Assist S4 dip switch 7 32 7 Factory Use S4 dip switch 8 32 8 Freeze Timer S4 dip switch 9 10 33 9 Float Switch Selector S5 dip switch 1 33 10 Refill Counter S5 dip switch 2 and 3 33 11 Minimum Harvest Time S5 dip switch 4 34 12 Anti Slush S5 dip switch 5 34 IV Refrigeration Circuit and Component Service Information 35 ...

Page 3: ...pplicable national state and local codes and regulations Electrical connection must be hard wired and must meet national state and local electrical code requirements Failure to meet these code requirements could result in death electric shock serious injury fire or severe damage to equipment The icemaker requires an independent power supply of proper capacity See the nameplate for electrical speci...

Page 4: ...ructions in this manual carefully to reduce the risk of costly water damage In areas where water damage is a concern install in a contained area with a floor drain Install the appliance in a location that stays above freezing Normal operating ambient temperature must be within 7 C to 38 C Do not leave the icemaker on during extended periods of non use extended absences or in sub freezing temperatu...

Page 5: ... Construction 1 KM 470AJ Water Supply Inlet Condenser Drier Control Box Spray Tubes Control Switch Water Pump Float Switch Compressor Thermostatic Expansion Valve Fan Motor Hot Gas Valve Cleaning Valve Inlet Water Valve Liquid Line Valve High Pres sure Switch ...

Page 6: ...mostatic Expansion Valve Compressor Hot Gas Valve High Pressure Switch Strainer Fan Drier Condenser Evaporator Discharge Line Suction Line Water Pump Thermistor Spray Tubes Inlet Water Valve Freeze Pump Out Water Tank Refrigeration Circuit Water Circuit Heat Exchanger Liquid Line Valve Cleaning Valve ...

Page 7: ...switch is placed in the ICE position Operation Flow Chart 1 1 Minute Fill Cycle Cycle Steps 2 Harvest Cycle WV time 6 min or the length of harvest minus HPT setting S4 dip switch 6 whichever is shorter Max harvest time 20 min Thermistor in control 3 Freeze Cycle Min freeze time 5 min Max freeze time freeze timer setting S4 dip switch 9 10 FS in control 4 Pump Out Cycle Factory set for every 10th c...

Page 8: ...lb icemaker shuts down Shutdown and Restart BC Operation Ice contacts BC bulb 2 Icemaker Off All components de energized 3 Ice Level Lowered No ice touching BC bulb Icemaker starts at 1 1 Minute Fill Cycle BC closed BC open All components de energized To 1 1 Minute Fill Cycle Shutdown Flow Chart ...

Page 9: ...oper voltage per nameplate and adequate water supply Check CB using the steps in II C Control Board Check Check dip switch settings to assure that S4 dip switches and S5 dip switches 1 through 5 are in the factory default position S4 dip switch 1 2 3 4 and 5 are cleaning adjustments and the settings are flexible For factory default settings see III C 1 Default Dip Switch Settings Note On 208 230 6...

Page 10: ...al W If 115VAC is present at HPS P and not at HPS BK HPS is open See HPS Diagnosis below If 115VAC is present at HPS BK check for 10 5VAC at CB K2 1 red wire to CB K2 2 red wire If 10 5VAC is not present check that the cleaning valve is closed and the interlock switch is closed Next check CT continuity If open replace CT b HPS Diagnosis Check that the condenser coil is not clogged or restricted Le...

Page 11: ...e suction line When the thermistor reaches 9 C CB reads 3 9 kΩ from the thermistor and turns harvest termination over to the harvest timer S4 dip switch 1 2 and S5 dip switch 4 WV and X11 relay are energized during harvest for a maximum of 6 min or the length of harvest minus HPT setting S4 dip switch 6 whichever is shorter See step 5b below a Comp Diagnosis Check that evaporator is warming If not...

Page 12: ...y If 115VAC is present on X10 relay terminal 4 R check control switch contact continuity between terminals 4 R and 5 W R If contacts are open replace control switch If contacts are closed and 115VAC is present between control switch terminal 5 W R and neutral W check PM capacitor and motor winding continuity 5c Initial Harvest Cycle Termination Diagnosis When the thermistor reaches 9 C CB reads 3 ...

Page 13: ...d check for 115VAC at CB K1 6 O to neutral W If 115VAC is present after PM energizes in harvest cycle replace CB If 115VAC is not present replace WV bypassing If HGV did not de energize at the end of harvest check for 115VAC at CB K1 2 P to neutral W If 115VAC is present 50 sec after PM energizes replace CB If 115VAC is not present replace HGV bypassing d PM Diagnosis Confirm water is flowing over...

Page 14: ...ove and clean CV replace rubber seat and spring if necessary If water tank is full see II E Float Switch Check and Cleaning for erratic operating FS 7 Pump Out Cycle LEDs 1 3 and 2 are on 10 20 second pump out Timing of the first pump out is determined by S4 dip switch 5 See the table below Control Board Settings S4 Dip Switch Setting Pump Out Frequency Control Board No 5 OFF Every 10 cycles After...

Page 15: ...eutral W If 115VAC is present on X12 terminal 6 DBU and not on X12 terminal 4 DBU check for 115VAC at X12 terminal 7 P to X12 terminal 8 W If 115VAC is not present check CB K1 pin 2 P wiring for loose connection If 115VAC is present and X12 is not energized check coil continuity Replace as needed If X12 is energized and X12 terminal 4 DBU does not have 115VAC replace X12 relay contacts sticking If...

Page 16: ... has proper voltage and the red LED is off replace CB If the secondary circuit does not have proper voltage check CT primary circuit Check for 115VAC at CB K1 connector pin 10 LBU to neutral W for 115VAC Always choose a white W neutral wire to establish a good neutral connection when checking voltages For additional checks see II H 1 No Ice Production 3 The OUTPUT TEST button provides a relay sequ...

Page 17: ...articularly at higher altitude locations Note A jumper 485134Z01 must be placed on CB red K4 connector Otherwise CB yellow BC OPEN LED is on and appliance will not start To check BC follow the steps below 1 Turn off the power supply 2 Remove the front panel then move the control switch to the OFF position 3 Remove the control box cover and base cover then clear any ice away from BC bulb 4 Disconne...

Page 18: ... to the bottom of the overflow pipe and be careful not to cross thread the overflow pipe 4 Remove the control box cover 5 Disconnect FS connector from CB K5 connector 6 Check for continuity across FS leads With the water tank empty FS should be open If open continue to step 7 If closed follow the steps in II E 2 Float Switch Cleaning After cleaning FS check it again Replace if necessary 7 Reconnec...

Page 19: ...water tank Remove the overflow pipe by turning it counterclockwise After the water tank has drained replace the overflow pipe and the rubber cap in their correct positions Note Be sure the overflow pipe o ring is in its correct position on the overflow pipe 4 Disconnect the vent tube and the flush tube from the top of FS then remove FS assembly and remove the rubber boot from the bottom of FS asse...

Page 20: ...orrect position See IV B Component Service Information 8 Reconnect the thermistor connector to CB K3 connector 9 Replace the control box cover in its correct position 10 Move the control switch to the ICE position 11 Replace the front panel in its correct position 12 Turn on the power supply 13 Once the harvest cycle starts Comp energizes begin timing the harvest cycle 14 The harvest timer and har...

Page 21: ... lines or components plugged 7 Control Transformer 115VAC 10 5VAC a Coil winding open or shorted 8 Control Board See II C Control Board Check a In alarm b Yellow BC OPEN LED on bin full K4 Jumper missing or loose c Defective 9 Water Supply a Water supply off or improper water pressure b External water filters clogged 10 Inlet Water Valve a Screen or orifice clogged b Coil winding open c Water valv...

Page 22: ... 1 Evaporator a Scaled up b Damaged 2 Cube Guides a Out of position b Damaged 3 Spray Tubes and or Spray Guides a Dirty b Out of position 4 Water Supply a Low water pressure b External water filters clogged c Insufficient water line size Minimum 1 4 Nominal ID 6 mm Nominal OD in the EU copper water tubing or equivalent 5 Inlet Water Valve a Screen or orifice clogged b Defective 6 Float Switch See ...

Page 23: ...n 3 Refrigerant Charge a Low 4 Control Board See II C Control Board Check a Freeze timer S4 dip switch 9 10 set incorrectly b Defective 5 Inlet Water Valve a Leaking by 6 Float Switch See II E Float Switch Check and Cleaning a Float does not move freely b Defective 7 Pump Motor a RPM too slow b Impeller damaged 8 Thermostatic Expansion Valve a Bulb loose or defective 9 Liquid Line Valve a Restrict...

Page 24: ...tive 7 Hot Gas Valve a Erratic or closed 8 Inlet Water Valve a Screen or orifice clogged 9 Compressor a Inefficient or off 10 Liquid Line Valve a Erratic or open 11 Thermostatic Expansion Valve a Defective Long Freeze Cycle 1 Evaporator a Scaled up dirty 2 Float Switch See II E Float Switch Check and Cleaning a Scaled up dirty b Float sticking c Defective switch 3 Inlet Water Valve a Leaking by 4 ...

Page 25: ...arvest pump time harvest assist all models and freeze time correction models with control board 2A7664 02 13 Is the cube guide positioned correctly 14 Are the evaporator separators positioned properly 15 Is the thermistor properly mounted tight and insulated 16 Is the TXV bulb properly mounted tight and insulated 17 Are splash guards in place if applicable Appliance of Operation Fill YES NO 18 Doe...

Page 26: ...tible to failure due to static discharge It is especially important to touch the metal part of the icemaker when handling or replacing the control board Do not touch the electronic devices on the control board or the back of the control board Do not change wiring and connections Do not misconnect K3 WHITE K4 RED and K5 BLACK because the same connector is used for the thermistor jumper and float sw...

Page 27: ...Closed LED green on continuously in thermostatic bin control application LED 2 X2 Relay LED 2 on K1 Connector Pin 2 LED 2 off K1 Connector Pin 3 LED 3 X3 Relay LED 3 on K1 Connector Pin 5 LED 3 off K1 Connector Pin 4 energized in freeze LED 4 X4 Relay K1 Connector Pin 6 LED 1 X1 Relay K1 Connector Pin 1 9 K2 Connector Control Transformer 10 5VAC S5 Dip Switch ALARM RESET Button S4 Dip Switch OUTPU...

Page 28: ... timer setting Alarms Type Alarm Notes 1 Beep High Evaporator Temp temperature 53 C Check for harvest problem stuck HGV or relay hot water entering unit stuck HM or shorted thermistor 2 Beep Harvest Backup Timer harvest 20 min for two cycles in a row Check thermistor open HGV not opening TXV or LLV leaking by low charge inefficient Comp 3 Beep Freeze Timer freeze freeze timer setting for two cycle...

Page 29: ... OFF OFF OFF OFF OFF ON OFF OFF OFF S5 Dip Switch Do Not Adjust J Control Board Dip Switch No 1 2 3 4 5 KM 470AJ OFF OFF OFF OFF ON Freeze Timer 9 10 Pump Out Frequency Control 5 Pump Out Time Harvest Time During Pump Out 3 4 Harvest Timer 1 2 Factory Use 8 Harvest Pump Time Harvest Assist 7 Do Not Adjust 1 2 3 4 5 6 7 8 9 10 ON S4 Dip Switch J Control Boards Harvest Pump Time Harvest Assist Durat...

Page 30: ...Harvest Time During Pump Out S4 dip switch 3 4 NOTICE On models with harvest pump timer do not adjust 3 off and 4 on Pump does not run in pump out rotation in this setting When a pump out is called for the pump motor stops for 2 sec then energizes in the reverse direction taking water from the bottom of the water tank and forcing pressure against the check valve seat allowing water to go through t...

Page 31: ...2nd freeze cycle 5 Harvest Pump Time Harvest Assist Duration S4 dip switch 6 NOTICE Factory set for proper operation Do not adjust Adjustment outside of the factory default setting may result in damage to the appliance Harvest pump time harvest assist duration is only active when S4 dip switch 7 is in the ON position In the factory default position the harvest pump time harvest assist duration sta...

Page 32: ...7 is in the on position and harvest begins X11 and X10 relays energize A latching circuit is created through the X11 and X10 relays For further details see VIII B Wiring Diagrams In the factory default position 50 sec before harvest termination LED 4 turns off inlet water valve and X11 relay de energize X10 relay remains energized through the latching circuit Next LED 3 turns on and control board ...

Page 33: ...ort at 1 800 233 1940 for recommendations S4 Dip Switch Setting Time min No 9 No 10 OFF OFF 60 OFF ON 50 ON OFF 70 ON ON 75 9 Float Switch Selector S5 dip switch 1 NOTICE Do not adjust This must be left in the factory default position or the icemaker will not operate correctly This dip switch setting allows use of this control board in single and dual float switch models This model uses a single f...

Page 34: ...per operation Do not adjust Adjustment outside the factory default setting may result in damage to the appliance This dip switch setting provides anti slush control during the freeze cycle When the evaporator temperature reaches 2 2 C the control board reads a 5 8kΩ signal from the thermistor and de energizes the water pump for 10 sec to melt ice slush and prevent ice slush from blocking the water...

Page 35: ... system if using an electronic leak detector and then raise the pressure using nitrogen gas 0 97MPa Do not use R 404A as a mixture with pressurized air for leak testing NOTICE Always recover the refrigerant and store it in an approved container Do not discharge the refrigerant into the atmosphere Do not leave the system open for longer than 15 min when replacing or servicing parts The Polyol Ester...

Page 36: ...l the new drier with the arrow on the drier in the direction of the refrigerant flow When brazing protect the drier by using a wet cloth to prevent the drier from overheating Do not allow the drier to exceed 121 C 2 Use an electronic leak detector or soap bubbles to check for leaks Add a trace of refrigerant to the system if using an electronic leak detector and then raise the pressure using nitro...

Page 37: ... scales if the service cylinder is not equipped with a dip tube invert the service cylinder then place it on the scales Open the high side valve on the gauge manifold 7 Allow the system to charge with liquid until the proper charge weight is met 8 If necessary add any remaining charge to the system through the low side NOTICE To prevent compressor damage use a throttling valve or liquid dispensing...

Page 38: ...clamp and holder then insulate it Hot Gas Valves Liquid Line Valves Replace the strainer if applicable Use copper tube of the same diameter and length when replacing valve lines Fan Motors Install a new capacitor Pump Motor Install a new capacitor Thermistor Attach the new thermistor to the suction line in the same location as the previous thermistor The thermistor should be at the 12 o clock posi...

Page 39: ...scoop using a neutral cleaner Rinse thoroughly after cleaning Bi Weekly Air Filters Inspect Wash with warm water and neutral cleaner if dirty Monthly External Water Filters Check for proper pressure and change if necessary Icemaker Exterior Wipe down with a clean soft cloth Use a damp cloth containing a neutral cleaner to wipe off oil or dirt build up Clean any chlorine staining rust colored spots...

Page 40: ...temperatures follow the instructions below 1 Remove the water from the icemaker water line 1 Turn off the power supply then remove the front panel 2 Close the icemaker water supply line shut off valve and open the icemaker water supply line drain valve 3 Allow the line to drain by gravity 4 Attach a compressed air or carbon dioxide supply to the icemaker water supply line drain valve 5 Make sure a...

Page 41: ...water tank has drained replace the overflow pipe and the rubber cap in their correct positions NOTICE Make sure the O ring is attached to the bottom of the overflow pipe and be careful not to cross thread the overflow pipe 4 Replace the base cover if applicable and front panel in their correct positions 5 Remove all ice from the dispensing unit ice storage bin Clean the storage bin liner using a n...

Page 42: ...posal The appliance contains refrigerant and must be disposed of in accordance with applicable national state and local codes and regulations Refrigerant must be recovered by properly certified service personnel ...

Page 43: ...43 VIII Technical Information We reserve the right to make changes in specifications and design without prior notice A Dimensions Specifications 1 KM 470AJ ...

Page 44: ...44 B Wiring Diagram 1 KM 470AJ High Pressure Switch Air Models Cut out 2 84 0 15 MPa Cut in 2 26 0 15MPa 0 ...

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