Hoshizaki 73168 service manual Removal and Replacement of Expansion Valve

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8)Braze the fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG.

9)Replace the removed evaporator parts in their correct positions.

10)Once the repair is complete, return to step 15 in "IV.B.1. Recovery Procedure" for refrigeration system cartridge replacement.

E.Removal and Replacement of Expansion Valve

Moisture in the refrigeration circuit may exceed drier capacity and freeze up at the expansion valve.

CAUTION

1.Always install a new drier every time the sealed refrigeration system is opened.

2.Do not replace the drier until after all other repair or replacement has been made. Install the new drier with the arrow on the drier in the direction of the refrigerant flow.

3.When brazing, protect the valve body and drier by using wet cloths to prevent the valve body and drier from overheating. Do not allow the valve body or drier to exceed 250°F (121°C).

1)Move the power switch to the "OFF" position, then unplug the unit.

2)Remove the panels.

3)Recover the refrigerant and store it in an approved container.

4)Remove the insulation and the expansion valve bulb on the suction line.

5)Remove the expansion valve cover and disconnect the expansion valve. Place the new expansion valve in position.

6)Remove the drier, then place the new drier in position.

7)Braze all fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG.

8)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 nitrogen gas (140 PSIG). DO NOT use R-404A as a mixture with pressurized air for leak testing.

9)Evacuate the system and charge it with refrigerant; see the nameplate for the required refrigerant charge.

10)Attach the expansion valve bulb to the suction line in the same location as the previous bulb. The bulb should be between the 10 and 2 o'clock position on the tube. Be sure to secure the bulb with the clamp and holder and to insulate it.

11)Place the expansion valve cover in position.

12)Replace the panels in their correct positions.

13)Plug in the unit, then move the power switch to the "ON" position to start the unit's cooling process.

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Contents Superior Degree Reliability Number Issued Revised Hoshizaki AMERICA, INC Contents Page Page Serious injury Important Safety InformationIndicates important information about the use and care UnitDimensions Specifications Nameplate RatingsII. General Information Construction Power Switch ON, Rail Cooling Switch Normal or LOW Power Switch ON, Rail Cooling Switch OFFSequence of Operation Cabinet Defrost Cool Down RestartRail Defrost Cabinet Defrost Power Switch ON, Rail Cooling Switch OFFOperation Power Switch ON, Rail Cooling Switch OFF CabinetRail Cooling Power Switch ON, Rail Cooling Switch Normal or LOW PositionCabinet and Rail Cooling Control Board Location Control BoardControl Board Layout Front RearAlarm Signal LED Display and Service Lock-OutService Menu Compressor Short Cycle ProtectionSwitch Settings Controls and AdjustmentsTemperature Display Energy Saving Mode Temperature SetpointCabinet Defrost Temperature Correction Factor Service Menu Access Service MenuService Menu Chart Control Board Check Procedure Alarm SignalsControl Board Replacement Perimeter Heater Thermistor CheckCompressor Protector Alarm Signals III. Service DiagnosisAlarm Priority Problem Reset, Corrections, and Adjustments Reset Options High Temperature Alarm E1Low Temperature Alarm E2 Cabinet Defrost Alarm E3 High Condenser Temperature Alarm clogged filter E7 Possible Causes Defrost Thermistor cabinet Malfunction Alarm E85a. Secondary Defrost Thermistor Rail, not used Condenser Thermistor Malfunction Alarm E9 Control Board Alarms EA and ED Service ChartNo Operation Cabinet Cooling Problem Possible Cause Remedy Rail Cooling Cabinet Defrost Other Service for Refrigerant Lines IV. Removal and Replacement of ComponentsRefrigerant Recovery Evacuation and Recharge R-404A BrazingPage Refrigerant Recovery Procedure Removal and Replacement of Refrigeration System CartridgePage Refrigeration System Pump‑Down Procedure Page Defrost Thermistor Rail Thermistor Removal and Replacement of Compressor Removal and Replacement of Cabinet Evaporator Removal and Replacement of Expansion Valve Removal and Replacement of Liquid Line Valve Removal and Replacement of Condenser Cabinet Thermistor Removal and Replacement of Thermistors and ThermostatDefrost Thermistor Rail Thermistor Defrost ThermostatCondenser Thermistor clogged filter Removal and Replacement of Defrost HeaterCabinet Fan Motor Removal and Replacement of Fan MotorsRail Fan Motor Condenser Fan MotorDoor Re-Hinging and Drawer Conversion Removal and Replacement of Door GasketWork Surface Cleaning and Maintenance InstructionsExterior Rail and Rail CoverCabinet Interior Door/Drawer GasketsPower Supply Connection MaintenanceRail Condensate Pan Air FilterShutdown and Long Storage HPR100A-D Refrigeration Circuit VI. Technical InformationHPR46A-D Wiring Diagrams2a. HPR72A-D Auxiliary Code U-5 and Earlier 2b. HPR72A-D Auxiliary Code U-6 and Later Awaiting Data