Service Manual REFRIGERATED BASE
Contents
1. Service Manual REFRIGERATED BASE gt MODEL RB 72 Please read this manual completely before attempting to install operate or service this equipment This manual is Copyright 2011 Duke Manufacturing Company All rights reserved Reproduction without written permission is prohibited Duke is a registered trademark of the Duke Manufacturing Company Duke Manufacturing Company 2305 N Broadway St Louis MO 63102 Phone 314 231 1130 Toll Free 1 800 735 3853 Fax 314 231 5074 www dukemfg com P N 219207C Service Manual for Refrigerated Base Model RB 72 MEM IMPORTANT WARNING AND SAFETY INFORMATION WARNING READ THIS MANUAL THOROUGHLY BEFORE OPERATING INSTALLING OR PERFORM ING MAINTENANCE ON THE EQUIPMENT WARNING FAILURE TO FOLLOW INSTRUCTIONS IN THIS MANUAL CAN CAUSE PROPERTY DAMAGE INJURY OR DEATH WARNING DO NOT STORE OR USE GASOLINE OR OTHER FLAMMABLE VAPORS OR LIQUIDS IN THE VICINITY OF THIS OR ANY OTHER APPLIANCE WARNING UNLESS ALL COVER AND ACCESS PANELS ARE IN PLACE AND PROPERLY SE CURED DO NOT OPERATE THIS EQUIPMENT CAUTION Observe the following Minimum clearances must be maintained from all walls and combustible materials Keep the equipment area free and clear of combustible material Adequate clearance for air openings e Operate equipment only on the type of electricity indicated on the specification plate e Retain this manual fo2. aking care to not block airflow to the fans Outside Unit Be sure that the unit has access to ample air avoid hot corners and locations near stoves and ovens Leveling Be sure that the units are placed on a firm flat surface floor Check for cracks in flooring or tile and avoid these areas if possible If necessary place support pads properly rated for the weight of the unit to bridge uneven or cracked flooring Level unit accordingly Stabilizing Use the leg adjustments to insure that the unit is solid to the floor surface at all six contact points Insure that the unit does not rock when pressure is applied to the top corners Electrical Connection The RB 72 is available as a 120VAC 60 Hz or as a 220VAC 50 Hz dependent on model All electrical connections should be performed by a certified electrician and should comply with local electrical codes for your municipality WARNING REFER TO THE AMPERAGE DATA LIST IN THE SPECIFICATIONS OR THE SERIAL TAG DATA AND YOUR LOCAL CODE OR THE NATIONAL ELECTRICAL CODE TO BE SURE UNIT IS CONNECTED TO THE PROPER POWER SOURCE A PROTECTED CIRCUIT OF THE CORRECT VOLTAGE AND AMPERAGE MUST BE RUN FOR CONNECTION OF THE SUPPLY CORD OR PERMANENT CONNECTION TO THE UNIT THE POWER MUST BE TURNED OFF AND DISCONNECTED WHENEVER PERFORMING MAINTENANCE OR RE PAIR FUNCTIONS Mn Service Manual for Refrigerated Base Model RB 72 MAINTENANCE Stainless Steel Care and Cl
3. eaning Stainless steel contains 70 80 iron which will rust It also contains 12 3096 chromium which forms an invisible passive film over the steel surface and acts as a shield against corrosion As long as the protective film remains intact the metal will not corrode However if the film is broken or contaminated outside elements can begin to breakdown the steel and begin to form rust or discoloration To prevent rust and discoloration on stainless steel several important steps need to be taken CAUTION Never use steel wool pads or wire brushes or scrapers Avoid AN cleaning solutions that contain alkaline or chloride Use alkaline based or non chloride cleaning solutions Anything containing chloride will damage the protective film on stainless steel Chlorides are found in household and industrial cleaners and also in hard water and salts If a chloride or alkaline cleaner has been used rinse repeatedly and dry thoroughly Always use only soft cloths or plastic scouring pads For routine cleaning use warm soapy water For stubborn stains use a non abrasive cleanser For heavy grease use a degreaser For best results rub with the grain of the steel Pitting and cracking are early signs of stainless steel breakdown But special stainless steel cleaners can restore and preserve the protective film If signs of breakdown appear thoroughly clean and dry all surfaces Begin regular application of a high quality stainless st
4. ect wiring Remove evaporator fan and fan vent mounting hardware Remove evaporator fan Install replacement evaporator fan and fan vent mounting hardware Using tags connect evaporator fan wiring Install evaporator control box cover fan and thermostat assembly 10 Install shelves 11 Connect unit to power source and test unit Refrigeration System Replacement General The refrigeration system assembly is located in the far right lower compartment behind the filter cover 10 T1 12 13 14 15 Disconnect unit from power source Remove filter cover Using a refrigeration charging unit evacuate refrigerant from the system according to Duke Manufacturing Service Bulletin Number 26 Remove expansion valve from refrigeration assembly Remove refrigeration assembly mounting hardware Tag and disconnect wiring at junction box Slide the refrigeration system assembly out through the front of the unit Install replacement refrigeration assembly onto slide bars Slide in refrigeration system assembly to original position Install refrigeration system assembly mounting hardware Install expansion valve and evaporator tubing to refrigeration system assembly Using tags connect wiring at junction box Connect unit to power source ChargesystemaccordingtoDukeManufacturing Service Bulletin Number 26 Install filter cover Mn Service Manual for Refrigerated Base Model RB 72 D
5. eel cleaner according to the manufacturer s instructions Again always rub with the grain of the steel for best results CAUTION Never use an acid based cleanser Be sure to clean all food products AN from any stainless surface Many food products contain acid which can deteriorate the finish Common foods include tomatoes peppers and other vegetables WARNING THE POWER MUST BE TURNED OFF AND DISCONNECTED AT ALL TIMES DURING MAINTENANCE OR REPAIR FUNCTIONS Service Manual for Refrigerated Base Model RB 72 MEM PREVENTIVE MAINTENANCE Cleaning the Condenser Coil Failure to maintain a clean condenser coil can initially cause high temperatures and excessive run times Continuous operation with dirty or clogged condenser coils can result in compres sor failure Neglecting the condenser coil cleaning procedures will void all warranties and repair or replacement costs associated with the compressor CAUTION Toclean the condenser never use ahigh pressure water wash which AN can damage electrical components located at or near the condenser coil Condensing Coil Figure 2 Location of Condensing Coil The condenser coil is located and accessed at the front of the unit see Figure 2 The condenser coil requires regular cleaning and should be done every 60 days However if large amounts of dust and grease accumulate sooner clean the condenser coil every 30 days For light dust use a soft non w
6. hoses as close to factory crimps as possible 2 Usetemporary valves to perform repair Duke Manufacturing will not reimburse the cost of permanently installed valves 3 Aftercompleting repair evacuate systemusing thetriple evacuation method described in Duke Manufacturing Service Bulletin Number 26 4 After completing proper evacuation method recharge system using proper refrigerant according to information on data plate 5 Continue crimping process hose just below temporary valve and again 2 below crimp 6 With crimp tool in place remove temporary valve 7 Braze shut end of process hose 8 Allow to cool for about 5 minutes 9 Remove crimp tool 10 Check brazed end for leaks Heater Thermostat Replacement General The heater thermostat is located on the far right front of the unit above the filter cover 1 Disconnect unit from power source Remove filter cover Remove thermostat cover which is mounted directly above the refrigeration system assembly Tag and disconnect thermostat wiring In upper heated compartment remove thermostat probe cover 6 Carefully remove thermostat probe 7 Tag and disconnect warning lamp at thermostat Remove thermostat knob Remove thermostat mounting hardware and thermostat 10 Install replacementthermostat and thermostat mounting hardware 11 Install thermostat knob 12 Using tags connect warning lamp at thermostat 13 Carefully install the
7. ire brush For heavier dust use a vacuum or blow with compressed air For heavy grease use a degreasing agent made specifically for condenser coils on refrigeration units Spray the degreasing agent on the coil and then blow with compressed air Never wash with high pressure water which can damage the electrical components located at or near the condenser coil Door Gasket Maintenance Door gaskets require regular cleaning to prevent mold and mildew build up and to maintain elasticity for proper seal function Warm soapy water is adequate for cleaning the gasket Avoid using full strength cleaning products which can cause the gasket to become brittle and result in improper seal function Never scrape or clean the gasket with sharp tools or knives which can tear the gasket Mn Service Manual for Refrigerated Base Model RB 72 Drain Maintenance Base Located at the rear of each unit is a drain hose which removes the condensation from the evaporator coil and deposits it into a drain pan for evaporation see Figure 3 Drain Hose Figure 3 Location of Drain Hose and Drain Pan If excessive water accumulates inside the unit check to see that the drain hose is connected from the evaporator housing to the drain pan If water accumulates underneath the unit check to see that the drain hose is located above the drain pan A level unit is essential for proper drainage Be sure to provide a level surface belo
8. o cold Set thermostat to a lower number for a warmer temperature Cabinet too cold Thermostat switch is stuck in the closed position Replace thermostat Drain hose plugged Clear drain hose Water in bottom of unit Drain hose loose or disconnected from drain pan Tighten or connect drain hose Duke Manufacturing Company 2305 N Broadway St Louis MO 63102 Phone 314 231 1130 Toll Free 1 800 735 3853 Fax 314 231 5074 www dukemfg com P N 219207
9. oor and Hinge Replacement General The door and hinge can be replaced 1 With the door closed remove the sheet metal cover from the door side of the hinge 2 While supporting the door remove three mounting screws and spacer from the unit side of the hinge 3 Repeatthe above procedure on the remaining hinge Remove the door Remove three screws and spacer from the door side of the hinges Remove the hinges 6 Inserthinges onthe door and secure with three screws and spacer 7 Position the door with hinges on the unit for installation Secure with three screws and spacer in each hinge 8 Install sheet metal covers over the door side of the hinges Door Gasket Replacement General The door gasket has a retaining panel 1 Remove gasket door panel and mounting screws Remove gasket and door panel Position new gasket and panel on door Secure with mounting screws Tighten screws evenly around door panel Recharging Refrigeration System General To analyze the performance of a refrigeration system temperature readings are recorded and converted to pressure readings using a standard pressure temperature chart When it is necessary to service a factory sealed refrigeration system and return it to its properly sealed condition strictly adhere to the following approved procedure Tools e Standard hand and refrigeration tools Refrigerant Type R 134A 4 5 ounces Charging Procedure NOTE P
10. pad ubE Hia app inate Palau SMS qubd GNIS Gad CIBUS 9 Door Gasket Replacement ccccccccccccecceeeee cette eee e eee ttrt ttrt e ener eect ee enemene nnn nnne nen nenne eren nennen 9 Recharging Refrigeration SyStemM issirinksi iiaa NKEA NANN iea 9 TOOS e Nbre E Re NP dE FTU e E UD FEIES 9 i oiobgircs o peut EAA 9 Heater Thermostat Replacement sse nennen nnn nnn 10 Heating Element Replacement enint nen en Pete akku uaa ERERRERE M E UNE FEE KK RN K idei ii 10 58 ELI PIN cte 1 m c aeeees 11 Service Manual for Refrigerated Base Model RB 72 MEM SPECIFICATIONS MODEL DESCRIPTION VOLTAGE AMPS PH RB 72 72 Refrigerated 120 VAC 60 Hz 8 8 1 Base 220 VAC 50 Hz 4 4 1 MODEL DESCRIPTION HEIGHT WIDTH LENGTH RB 72 72 Refrigerated 38 00 In 33 50 In 72 00 In Base INSTALLATION Location The unit represented in this manual is intended for indoor use only Be sure the chosen location has a floor or counter strong enough to support the total weight of the unit Reinforce the floor or counter if necessary to provide for maximum loading For the most efficient operation be sure to provide good air circulation inside and out The outline dimensional drawing for the unit is shown below in Figure 1 Figure 1 72 Refrigerated Base RB 72 Inside Unit Provide adequate space along the front back and sides t
11. r future reference Mn Service Manual for Refrigerated Base Model RB 72 CONTENTS SPECIFIGCALIONS erica ucaadiree tence nauaanesuasivialeacnisinadaeint ct ceases au abet E EE S A Aaa 4 INSTALEA TION mere PTT 4 LOCATON m 4 Iriside Ant iode edere aedes Rn nd nt n x nea nnd ten Ran om qu ap em nbi n a en Re Ek eni der d ena 4 OUTSIDE m A 4 E Cl em 4 eA NUN MARNE E SEE 4 Electrical Connection sessssssssssssssssssssssssssseeeeeeeneeennennne nnne nnne n hehehe nnne nnne nnne 4 Ul gliz7in elc 5 Stainless Steel Care and Cleaning sissie REM 5 PREVENTIVE MAIN TENANCE miasastitgnncitpalgnns atia mtt bx mpi dus ticcng cda o titu to gne rcd EEN 6 Cleaning the Condenser UTI PN Et 6 Door Gasket Maintenance ener nen nennen rennen rens 6 Drain Maintenance Base oree e e enne nnnm nnne nnne nnne nennen nennen nennen 7 PARTS REPLACEMEN Me 7 Thermostat Replacement c ceccececceeceeeaaeeeaeeaaeeeaeeaaeeaaeeaeceaeeeaecececeaeceaeceaeeeaeeeeeceeseeeeseeeeeees 7 Evaporator Fan Replacement sssssssssssesseeseees eene nennen herren nennen 8 Refrigeration System Replace Tell socia sateen p bi bars Oir t den triste teda ind t etu nenas 8 Door and Hinge IeplacerDilllsisyasccpaizissta toa att netug bua cti
12. rior to refrigeration system service special care must be taken during the evacuation process to remove air moisture and other non condensables from the system Duke Manufacturing recommends the following triple evacuation method Failure to follow this procedure may result in poor refrigeration system performance 1 Evacuate system to 1500 microns 2 Break vacuum to 2 psig with dry nitrogen If dry nitrogen is unavailable use same type of refrigerant as used in system Evacuate system to 1500 microns 4 Break vacuum to 2 PSIG with dry nitrogen If dry nitrogen is unavailable use same type of refrigerant as used in system 5 Evacuate system to 500 microns The system is now ready to receive refrigerant charge according to information on data plate CAUTION Never use oxygen or acetylene in place of dry nitrogen orrefrigerant AN for leak testing Aviolentexplosion may result causing property damage personal injury or death When using nitrogen to pressure test always use a pressure regulator Failure to do so will result in extremely high pressure of the compressor or other system components and resultin property damage personal injury and death NOTE Prior to repair ensure there is enough process hose approximately 12 present to complete the repair using the above procedure If not install a new process hose before repair sequence 1 Install a temporary access valve on the high and low side of process
13. rmostat probe 14 Install thermostat probe cover 15 Using tags connect thermostat wiring 16 Install thermostat 17 Install filter cover 18 Connect unit to power source Heating Element Replacement General The heating elementis located in the upper heated compartment 1 Disconnect unit from power source 2 Remove filter cover Remove thermostat cover which is mounted directly above the refrigeration system assembly 4 Tag and disconnect heating element wiring In upper heated compartment remove heating element mounting hardware and heating element from support brackets 6 Install replacement heating element and mounting hardware 7T Using tags connect heating element wiring 8 Install thermostat cover 9 Install filter cover 10 Connect unit to power source TROUBLESHOOTING SYMPTOM CAUSE REMEDY Cabinet too warm Unit not plugged in Plug unit in Thermostat set too warm Set thermostat to a higher number for a colder temperature Thermostat switch stuck open in coldest position Replace thermostat Doors not sealing Torn or damaged door gaskets Adjust doors Replace gaskets Evaporator fan not running Check and repair or replace motor Condenser fan motor not running Check and repair or replace motor Dirty condenser coil or filter Clean coil or filter Refrigerant leak Find leak repair and recharge Thermostat set to
14. w the unit especially if the floor is not level Keep the drain pan free from dirt dust and debris to prevent water from backing up and overflowing from the drain pan onto the floor PARTS REPLACEMENT Thermostat Replacement General The thermostat is located inside the cooling compartment and is accessible through the doors Disconnect unit from power source 2 Remove shelves Remove evaporator control box cover fan and thermostat assembly Tag and disconnect thermostat wiring Remove thermostat probe from evaporator coil 6 Remove knob thermostat and mounting screws Remove thermostat from control box Install replacement thermostat knob and mounting screws NOTE Do not kink thermostat probe NOTE To ensure proper operation place 8 of thermostat probe into evaporator coil 9 Install thermostat probe in evaporator coil 10 Using tags connect thermostat wiring 11 Install evaporator control box cover fan and thermostat assembly 12 Install shelves 13 Connect unit to power source and test unit Service Manual for Refrigerated Base Model RB 72 i 7777777 Evaporator Fan Replacement General The evaporator fan is located and accessed inside the cooling compartment and is removed as an assembly from the back panel 1 Disconnect evaporator fan wiring from power source Remove shelves Remove evaporator control box cover fan and thermostat assembly Tag and disconn
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