Hoshizaki RF28A Service Manual
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Hoshizaki RF28A Service Manual

Hoshizaki RF28A Service Manual

Commercial refrigerators & freezers
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Hoshizaki
Hoshizaki America, Inc.
"A Superior Degree
of Reliability"
www.hoshizaki.com
Commercial Refrigerators & Freezers
Models
RR28A
RR55A
RF28A
RF55A
SERVICE MANUAL
Number: 73139
Issued: 8-31-2006

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Summary of Contents for Hoshizaki RF28A

  • Page 1 Hoshizaki America, Inc. “A Superior Degree of Reliability” www.hoshizaki.com Commercial Refrigerators & Freezers Models RR28A RR55A RF28A RF55A SERVICE MANUAL Number: 73139 Issued: 8-31-2006...
  • Page 2 HOSHIZAKI provides this manual primarily to assist qualified service technicians in the service and maintenance of the unit. Should the reader have any questions or concerns which have not been satisfactorily addressed, please call, write or send an e-mail message to the HOSHIZAKI Technical Support Department for assistance. HOSHIZAKI AMERICA, INC.

  • Page 3: Table Of Contents

    I. Specifications... 5 A. Nameplate Ratings ... 5 B. Construction ... 5 C. Dimensions ... 5 1. RR28A, RF28A... 6 2. RR55A, RF55A... 7 II. General Information ... 8 A. Sequence of Operation ... 8 B. Time-Temperature Control Chart ... 9 C.
  • Page 4 Q. Removal and Replacement of Control Boards ... 40 R. Removal and Replacement of Fan Motors... 41 S. Door Re-Hinging ... 42 V. Cleaning Instructions ... 43 VI. Wiring Diagrams ... 44 A. RR28A ... 44 B. RR55A... 45 C. RF28A... 46 D. RF55A ... 47...

  • Page 5: Specifications

    B. Construction Access Valve Condenser Condenser Filter Control Defrost Thermal Fuse Safety Defrost Thermostat C. Dimensions RR28A, RF28A 571.5 1512.0 RR55A RF55A Design Pressure Amperes Intentionally Left Blank Intentionally Left Blank 450 PSIG 250 PSIG Intentionally Left Blank Condenser Fan...

  • Page 6: Rr28A, Rf28A

    1. RR28A, RF28A Units: mm...

  • Page 7: Rr55A, Rf55A

    2. RR55A, RF55A Units: mm...

  • Page 8: General Information

    [Minimum 3 minutes] 1. Compressor off 2. Condenser fan off Defrost End Defrost thermistor reaches defrost termination temperature [refrigerator = 68°F 4.1 kΩ (20°C) ; freezer kΩ = 95°F (35°C) 1.2 or defrost timer reaches 1 hour 1. Defrost heater off 2.

  • Page 9: Time-Temperature Control Chart

    B. Time-Temperature Control Chart...

  • Page 10: Control Board

    C. Control Board • A HOSHIZAKI exclusive solid-state control is employed in all Hoshizaki refrigerators and freezers. • All models are pretested and factory-adjusted. 1. Fragile, handle very carefully. 2. A control board contains integrated circuits, which are susceptible to failure due to static discharge.

  • Page 11: Control Board

    Rear K311 (6 pin) Relay Wiring Harness Board Part Number Chip Revision K251 (5 pin) K101 (3 pin) Transformer (12V) K151 (10 pin) Thermistor Wiring Harness F101 K361 (9 pin) 3 Amp Fuse Note: Fuse at position F101 on board is not used currently. The board can function without this fuse.

  • Page 12: Settings And Diagnostics

    D. Settings and Diagnostics Various settings and diagnostic information can be controlled via the display panel. The display panel is located behind the front panel. To open the front panel, swing the bottom of the panel up and allow the panel hinges to catch securely on the side panel frames in the locked position.

  • Page 13: Settings And Diagnostics Menu

    2) To change the setpoint, press and hold the down button. Refrigerator +21 to +54°F Freezer 3) The new setpoint will be saved automatically 10 seconds after releasing the buttons. Note: For refrigerators and freezers, the temperature differential for the compressor to turn off is -3.6°F (-2.0°C).

  • Page 14: A) Defrost Interval (F0)

    a) Defrost Interval (F0) This unit is preset at the factory to defrost once every 6 hours for general conditions. However, if it is determined that this interval does not suit actual conditions, the interval can be changed. To change the defrost interval, follow the steps below. 1) Press and hold both the not displayed, press the MANUAL DEFROST button until "F0"...

  • Page 15: C) High Temperature Alarm Delay Time (F3)

    4) Press the up or .9°F increments. Note: The - value can be adjusted between -0.9 and -6.3°F in .9°F increments (-0.5 to -3.5°C in .5°C increments). 5) Press the service button to save the - (minus) setting. The - (minus) sign will turn off and the display will change to the + (plus) differential setting.

  • Page 16: E) Temperature Display - °F Or °C (F5)

    Note: The time can be 0 or 60 minutes. The display corresponds to time as follows: 3) Press the service button to save the setting. 4) Press the MANUAL DEFROST button to return to the menu screen. Press and hold both the button and the and return to the temperature display.

  • Page 17: G) Compressor Run Time (F7)

    3) To reset the alarm history, press and hold both the DEFROST button for 5 seconds. 4) Press the MANUAL DEFROST button to return to the menu screen. Press and hold both the button and the and return to the temperature display. g) Compressor Run Time (F7) To display the compressor run time between the two most recent defrosts, follow the steps below.

  • Page 18: Cabinet Temperature Correction (Calibration Factor)

    The current correction calibration Setting Range -9.0 to 9.0°F in 0.9°F increments (-5.0 to 5.0°C in 0.5°C increments) up or down button to increase or decrease the value. Default Refrigerator Freezer 18 (1.8°F) 36 (3.6°F) (10 (1.0°C)) (20 (2.0°C))

  • Page 19: Service Diagnosis

    III. Service Diagnosis A. Alarm Codes If an error occurs, the alarm code and cabinet temperature are displayed in 1-second intervals. See the table below for a general description of the problem, then see the rest of this section for detailed instructions. Alarm Code Problem High Temperature Alarm Cabinet temperature has exceeded set...

  • Page 20: Alarm Display Priority

    1. Alarm Display Priority If multiple alarms occur simultaneously, only the alarm with the higher priority is displayed. Error Code Priority Description EEPROM Verification or Read Error Alarm EEPROM Write Error Alarm Defrost Thermistor Malfunction Alarm Clogged Filter Thermistor Malfunction Alarm High Pressure Alarm Clogged Filter Alarm Defrost Alarm...

  • Page 21: Alarm Details And Countermeasures

    2. Alarm Details and Countermeasures a) High Temperature Alarm (E1) If the cabinet temperature exceeds the setpoint temperature by 18°F (10°C) or more for more than x minutes, "E1" is displayed. The default value of x is "2" (120 minutes). The value of x can be changed under F3 on the Settings and Diagnostics Menu.

  • Page 22: B) Low Temperature Alarm (E2)

    b) Low Temperature Alarm (E2) If the cabinet temperature drops below the setpoint temperature by 9°F (5°C) or more for more than y minutes, "E2" is displayed. The default value of y is "1" (60 minutes). The value of y can be changed under F4 on the Settings and Diagnostics Menu. (0=0; 1=60 minutes) Note: •...

  • Page 23: C) Defrost Alarm (E3)

    c) Defrost Alarm (E3) If the defrost thermistor does not terminate defrost in one hour after defrost begins, "E3" is displayed. When "E3" is displayed, the next step in the defrost termination process (drain - fan delay - defrost display delay) begins. Reset Options To reset the alarm, turn the unit off and then back on.

  • Page 24: E) Clogged Filter Alarm (E7)

    e) Clogged Filter Alarm (E7) The unit is equipped with a filter for protecting the condenser from dirt, oils, grease, etc. The filter promotes clean condenser surfaces and efficient operation and should be checked twice monthly and cleaned when necessary. The unit is also equipped with a sensor (the clogged filter thermistor) to determine if this filter is excessively dirty.

  • Page 25: F) Defrost Thermistor Malfunction Alarm (E8)

    f) Defrost Thermistor Malfunction Alarm (E8) If input from the defrost thermistor is below the defrost open circuit detection point (equivalent to -67°F (-55°C)), "E8" is displayed. "E8" is also displayed when input from the defrost thermistor is above the defrost thermistor short circuit detection point (equivalent to 122°F (50°C)) for 10 minutes or more.

  • Page 26: G) Clogged Filter Thermistor Malfunction Alarm (E9)

    g) Clogged Filter Thermistor Malfunction Alarm (E9) If the input from the clogged filter sensor is below the clogged filter sensor open circuit detection point (equivalent to -7.6°F (-22°C)), "E9" is displayed. "E9" is also displayed when input from the clogged filter sensor is above the clogged filter sensor short circuit detection point (equivalent to 186.8°F (86°C)) for 10 minutes or more.

  • Page 27: H) Control Board Error Alarms (Ea And Ed)

    h) Control Board Error Alarms (EA and ED) "EA" is displayed when an EEPROM write error is detected. "ED" is displayed when an EEPROM verification or read error is detected. Reset Options Replacing the control board with a functioning replacement control board will eliminate this error condition.

  • Page 28: Diagnostic Chart

    B. Diagnostic Chart Problem Possible Cause [1] Compressor will a) Power Supply not start—no current draw. b) Cord and Plug c) Circuit Breaker (kitchen) d) Transformer e) Wiring to Control Board 1. Loose connection(s). f) Voltage g) High Pressure Switch h) Thermistor i) Control Board j) Compressor Overload...
  • Page 29 1. Remove blockage by interior. removing or redistributing food product. 1. Warm food recently 1. Allow time for unit placed in refrigerator. to return to setpoint temperature. 1. "OFF" position. 1. Move to "ON" position. 2. Loose connection(s). 2. Tighten or reconnect.
  • Page 30 Problem Possible Cause d) Compressor Relay e) Control Board [8] Evaporator does a) Defrost Thermistor not defrost b) Defrost completely. c) Defrost Heaters d) Safety Defrost Thermostat e) Defrost Heater Thermal Fuse f) Evaporator Shroud Heater [9] Defrost cycle a) Defrost Thermistor lasts too long.
  • Page 31 Problem Possible Cause [11]Abnormal Noise a) Fasteners b) Compressor c) Fan d) Relay Remedy 1. Loose fasteners allow 1. Tighten fasteners. vibration of part. 1. Problem with mount. 1. Properly mount compressor. Replace any missing grommets. 2. Floodback to 2. Check for signs of compressor.

  • Page 32: Thermistor Check

    C. Thermistor Check A thermistor (semiconductor) is used for the cabinet control sensor and defrost termination sensor. The resistance varies depending on temperature. No adjustment is required. If necessary, check for resistance between thermistor leads and visually check the thermistor mounting. Temperature °F °C...

  • Page 33: Removal And Replacement Of Components

    5) Disconnect the vacuum pump and attach a refrigerant service cylinder to the low-side line. Remember to loosen the connection, and purge the air from the hose. See the nameplate for the required refrigerant charge. Hoshizaki recommends that only virgin refrigerant be used.

  • Page 34: Brazing

    B. Brazing 1. Refrigerants R-404A and R-134a are not flammable at atmospheric pressure and ambient temperature. 2. Refrigerants R-404A and R-134a themselves are not explosive or poisonous. However, when exposed to high temperatures (open flames) these refrigerants can be decomposed to form hydrofluoric acid and carbonyl fluoride, both of which are hazardous.

  • Page 35: Removal And Replacement Of Drier

    D. Removal and Replacement of Drier Always install a new drier every time the sealed refrigeration system is opened. Do not replace the drier until after all other repair or replacement has been made. 1) Turn off the power supply, and unplug the unit. 2) Remove the panels.

  • Page 36: Removal And Replacement Of Defrost Heater

    Clogged Filter Thermistor 3) The thermistor element is secured to the condenser outlet pipe with a clip. Remove the clip and replace the thermistor. Clip the new thermistor to the same location as the previous thermistor. 4) Replace the panels in their correct positions. 5) Plug in the unit, and turn on the power supply.

  • Page 37: Removal And Replacement Of Capillary Tube / Heat Exchanger / Suction Line

    5) Wire tie the new thermal fuse in the same position as the old fuse. Make wiring connections outside of the cabinet. 6) Replace the parts and panels in their proper positions in the reverse order of the removal procedure. 7) Plug in the unit, and turn on the power supply.

  • Page 38: Removal And Replacement Of Primary Drain Tank Thermostat

    K. Removal and Replacement of Primary Drain Tank Thermostat 1) Turn off the power supply, and unplug the unit. 2) Remove the panels. 3) Remove the drain tank cover. 4) Remove the thermostat bulb from the heater element at the bottom of the tank. 5) Remove the thermostat assembly.

  • Page 39: Removal And Replacement Of Condenser

    4) Remove the panels and brackets. 5) Disconnect all wiring connections from the control boxes. 6) Remove the four hex head bolts securing the refrigeration unit to the cabinet. 7) Recover the refrigerant and store it in an approved container. 8) Disconnect the evaporator tubing next to the compressor.

  • Page 40: Removal And Replacement Of Door Gasket

    12) Replace the parts and panels in their proper positions in the reverse order of which they were removed. Be sure to clip the clogged filter thermistor in the same location as previous. 13) Plug in the unit, and turn on the power supply. P.

  • Page 41: Removal And Replacement Of Fan Motors

    4) Carefully remove the control board. 5) Identify the part number and software revision of the new board and make sure it is interchangeable with the old board. 6) Install the new board in the control box taking care not to damage it. 7) Hook all wiring connections back to the control board.

  • Page 42: Door Re-Hinging

    4) Remove the fan motor. Note the routing of the wiring. 5) Install the new motor. Be sure to route the wiring the same way as the previous motor with no slack around the fan motors. Make wiring connections outside of the cabinet. 6) Replace the parts and panels in their proper positions in the reverse order of the removal procedure.

  • Page 43: Cleaning Instructions

    V. Cleaning Instructions A. Stainless Steel Exterior Wipe the exterior occasionally with a clean, soft cloth. Use a damp cloth containing a neutral cleaner to wipe off oil or dirt build up. B. Stainless Steel Interior Spills should be wiped up promptly to avoid unpleasant odors. The cabinet interior should be cleaned periodically with a mild soap or detergent.

  • Page 44: Wiring Diagrams

    VI. Wiring Diagrams A. RR28A Before diagnosing and/or servicing the unit, confirm that you have the proper wiring diagram by checking against the diagram located inside the front panel. Intentionally Left Blank CAUTION...

  • Page 45: Rr55A

    B. RR55A Intentionally Left Blank CAUTION Before diagnosing and/or servicing the unit, confirm that you have the proper wiring diagram by checking against the diagram located inside the front panel.

  • Page 46: Rf28A

    C. RF28A CAUTION Before diagnosing and/or servicing the unit, confirm that you have the proper wiring diagram by checking against the diagram located inside the front panel.

  • Page 47: Rf55A

    D. RF55A Intentionally Left Blank CAUTION Before diagnosing and/or servicing the unit, confirm that you have the proper wiring diagram by checking against the diagram located inside the front panel.

This manual is also suitable for:

Rf55aRr28aRr55a

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