Hoshizaki JWE-620UA-6B service manual Thermistor Check

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E. Thermistor Check

If the error code “H1” “H2” “H3” or “H4” or an abnormal temperature [above 231°F (111°

C)or below -6°F (-21°C)] appears in the display, or the wash tank water boils, check the thermistor(s) according to the procedure below. If replacement is required, see “IV.M. Removal and Replacement of Thermistor.”

1)Move the power switch (GFCI) to the “OFF” position, then turn off the power supply. Lockout/Tagout to prevent the power from being turned back on inadvertently.

2)Remove the control box cover, then disconnect the CN7 connector from the control board (see “II.D.2. Control Board Layout”).

3)To check the wash tank thermistor, check the resistance across the brown wires (#1 and #2). To check the internal booster tank thermistor, check the resistance across the purple wires (#3 and #4). See the table below for proper resistance and temperature relations.

Temperature [°F (°C)]		Resistance [kΩ]
194	(90)	4.30 to 4.62
176	(80)	5.87 to 6.38
158	(70)	8.13 to 8.96
140	(60)	11.5 to 12.8
104	(40)	24.3 to 28.0
68 (20)		56.3 to 67.1
32	(0)	145.6 to 180.6

4)If any problem is found, replace the thermistor according to “IV.M. Removal and Replacement of Thermistor.”

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Contents Model JWE-620UA-6B Hoshizaki AMERICA, INC Contents Page Important Safety Information Display Speciﬁcations Speciﬁcation SheetNameplate Rating Dimensions/Connections Dishwasher II. General Information A. ConstructionInternal Booster Tank Auxiliary Code U-1, U-2, U-3, V-0, A-0 Control BoxAuxiliary Code A-1 and Later Auto Fill lamp ﬂashing and RINSE, STANDARD, or Long lamp on Sequence of OperationAuto Fill Cycle Wash Cycle Rinse Cycle STANDBY/CLEANING Button StartDrain Rinse lamp ﬂashingSequence of Operation Flow Chart Auxiliary Code A-1 and Later Control Board Location Control Board and Operation BoardCN5 Control Board LayoutCN9 Control Board DiagramX10 Mode Lamps Error CodesReady Lamp Auto Fill LampSTANDBY/CLEANING Button Mode ButtonService Menu Access Standby LampDefault Service Menu Chart Auxiliary Code U-1, U-2, U-3, V-0, A-0Service Menu Chart Auxiliary Code A-1 and Later Temperature Display Internal Booster Tank Energy Saving Mode Error CodesBuzzer Special ModesAlert Function Auxiliary Code A-1 and Later Continuous Wash ModeConsecutive Rinse Mode OFF Switch Open/Closed Display Mode III. Service DiagnosisDiagnostic Procedure Page Error Code Table Error CodesError Code Log Auto Fill Error A1 Error Code DetailsInternal Booster Tank Auto Fill Error A2 Wash Tank Water Level Error A3 Defective Replace Control Board Repair or replace Replace Wash Tank Thermistor Error H1, H2 Internal Booster Tank Thermistor Error H3, H4 Eeprom Error H6 ROM/RAM Error H5Phase Reversal Error H7 Unit Will Not Start Service Flow ChartsPage Dishes Not Clean Page Inadequate Rinse Dishwasher Will Not Start When Door Closed Wash Tank Water Boils No or Inadequate Detergent/Rinse Aid SupplyWash Tank Water Not Draining Float Switch Cleaning Float Switch Check and CleaningFloat Switch Check Thermistor Check Removal of Panels IV. Removal and Replacement of ComponentsAccessing the Control Box Page Removal and Replacement of Internal Booster Tank Removal and Replacement of Wash Pump Motor Removal and Replacement of Rinse Pump Motor Removal and Replacement of Handle Removal and Replacement of Door Removal and Replacement of Spring Removal and Replacement of Spring UnitAdjustment of Door Opening/Closing Force Removal and Replacement of Flush Pipe Packing Installation Instructions Removal and Replacement of Thermistor Operation Board Removal and Replacement of Control Board or Operation BoardControl Board Page Cleaning and Maintenance Instructions Daily Maintenance Pump Filter Water Level Sensor Location Front Self-Cleaning Monthly Inspection Weekly MaintenanceDescaling As Required Shutdown Long Storage, Relocation, Disposal, Transfer VI. Operating Instructions VII. Technical Information Water Circuit Auxiliary Code U-1, U-2, U-3, V-0, A-0 Wiring DiagramAuxiliary Code A-1 and Later