Bunn WDG-2 User's Manual
Contents
1. 1 Disconnect grinder from the power supply VEL TO J1 1 2 Remove all wires from the switch terminals 3 Place the selector switch in the left position I PLU TO RIGEN MOTOR 4 Check for continuity across the center and right terminals on the rear of the switch VIO TO 4 3 5 Continuity must not present across the center WHI BLU TO LEFT MOTOR and left terminals on the rear of the switch REAR VIEW 6 Check the bottom row then the top row of ter minals Motors If continuity is present as described proceed to 77 If continuity is not present as described replace the switch 7 Place the selector switch in the right position 8 Check for continuity across the center and left terminals on the rear of the switch 9 Continuity must not be present across the cen ter and right terminals on the rear of the switch 10 Check the bottom row then the top row of ter minals If continuity is present as described reconnect the wires the switch is operating properly If continuity is not present as described replace the switch Removal and Replacement 1 Remove all wires from the switch terminals 2 Compress the clips inside the front of the hous ing and gently push the switch through t2. INSTALLATION amp OPERATING MANUAL BUNN O MATIC CORPORATION POST OFFICE BOX 3227 SPRINGFIELD ILLINOIS 62708 3227 PHONE 217 529 6601 FAX 217 529 6644 10854 0000 3 00 1995 0 Corporation CONTENTS Treppe 2 ERREUR 2 Usei NOTICES 3 Electrical Requirements sn 4 Operating 15 8 4 Initial Set Up esses rne tnn tnn 5 Cleaning d Baisse ben eii rats 6 Coffee Grinding 202 2 200 002 0400000000000000000000000000 6 Adjustments ce 7 Trouble Shooting sss 9 12 thru 23 Wiring Diagrams 24 25 INTRODUCTION This equipment will store up to six pounds of whole bean coffee in each of two hoppers and grind it to a preset grind and amount into an awaiting funnel and filter from most commercial drip coffee brewers The equipment is only for indoor use on a sturdy counter or shelf Adequate space must be available above the grinder to raise the lids when adding beans Use only with whole bean coffee The grind is preset at the factory to drip specifications as set forth by the United States Department of Commerce and adopted by the Coffee Brewing Center of the Pan American Coffee Bureau Adjustments may be made to alter both the amount and
3. automatically after the preset amount of ground coffee is dispensed into the funnel Remove the funnel from the grinder and level the bed of grounds by gently shaking The loaded funnel is now ready for use in any commercial drip coffee brewer according to the manufacturer s instructions 5 P931 P934 STEP 1 STEP 72 STEP 73 P933 STEP 4 STEP 5 9 8 10854 030300 ADJUSTMENTS The grind can be set from fine to very coarse The grind may be adjusted for use in most commercial coffee brewers The following procedures should be used to make adjustments NOTE On DG 2 grinders a change in the burr adjustment will also change the amount dispensed Any adjust ment to the burrs should be followed by an adjustment of the timer Burr Adjustment 1 Unplug the grinder and empty all beans from the 5 2 Plug in the grinder place funnel with filter into the funnel rails Momentarily press the off on start switch to the START lower position with desired hopper selected and release run a few grind cycles until all of the coffee in the grind chamber is dispensed 3 Remove the upper front inspection panel 4 Loosen the burr adjustment screw from its locked position 5 Hand loosen the adjustment locking nut around the screw approximately one turn 581 6 Make sure funnel with filter is still in place in the funnel rails Press the off on start switch to the START lower position and release slowly
4. for the most likely problems encountered If the problem remains after exhausting the troubleshooting steps contact the Bunn O Matic Technical Service Department Inspection testing and repair of electrical equipment should be performed only by qualified service personnel All electronic components have 120 volt ac and low voltage dc potential on their terminals Shorting of terminals or the application of external voltages may result in board failure Intermittent operation of electronic circuit boards is unlikely Board failure will normally be permanent If an intermittent condition is encountered the cause will likely be a switch contact loose connection at a terminal or crimp Make certain that all electrical connections are tight and isolated WARNING Exercise extreme caution when servicing electrical equipment Turn power OFF when servicing except when electrical tests are specified Follow recommended service procedures Replace all protective shields or safety notices Problem Probable Cause Remedy Grinder will not start 1 No power or incorrect voltage A Plug in the grinder 2 Off On Start switch 3 A Timer DG 2 B Weigh Control Board WDG 2 4 Motor overload protector 11 B Check the voltage at the wall outlet with a voltmeter It must be 120 volts ac A Momentarily press the Off On Start switch to the START lower position B Refer to Service Off On Start sw
5. turn the adjusting screw in a clockwise direction until a metallic whine is heard due to the rubbing of the grinding burrs It may be necessary to start more than one grind cycle to obtain this sound 7 Make a mark with a pen on the decal to note the position of the arrow on the grind adjustment screw 8 The following settings approximately correspond to the CBC recognized grinds All are referenced from the arrow position marked in step 7 FINE GRIND Rotate the adjusting screw 7 hash marks in a counterclockwise direction DRIP GRIND Rotate the adjusting screw 8 hash marks in a counterclockwise direction REGULAR COARSE GRIND Rotate the adjusting screw 12 hash marks in a counterclockwise direction NOTE Exact adjustment will vary according to bean roast or added flavoring 9 Hold the adjusting screw in its set position with a screwdriver while tightening the lock nut to a snug position by hand The lock nut should now be tight against the burr housing front cover 10 Repeat steps 1 thru 9 for remaining hopper if desired 11 Reinstall upper front inspection panel Timer Adjustment DG 2 1 2 3 4 Unplug the grinder and remove the lower front inspection panel Determine the grind setting The factory setting is drip to determine other settings refer to the previous section Use the instructions below to find the approximate timer setting for the grind and amount of coffee desired Plug in grinder and select left or
6. D TO WEIGH CONTROL ASSEMBLY ORA TO WEIGH CONTROL ASSEMBLY 21 10854 030300 SERVICE cont Fan Location The fan is mounted on upper part of the rear in spection panel Test Procedure 1 Unplug the grinder 2 To gain access remove the rear panel with fan attached 3 Disconnect fan motor leads from the main har ness 4 Check voltage across the WHT RED and WHT leads to the main harness with a voltmeter Plug in the grinder With the OFF ON START switch in the center ON position the indication must be 120 volts AC 5 Unplug the grinder If voltage is present as described replace the fan If voltage is not present as described refer to wiring diagrams and check the wiring harness Removal and Replacement Remove rear panel with fan attached Disconnect fan motor leads from main harness Remove four 76 32 flat head screws and lock nuts attaching fan and fan guard to rear inspec tion panel Discard fan and set guard screws and locknuts aside for reinstallation 4 Reinstall fan guard and new fan to the rear panel making sure the air flow direction is away from rear panel 5 Connect leads from fan to the main wiring harness 6 Reinstall rear panel Oe 22 Fuse Location The fuse is located in the fuse holder on the rear of grinder near the bottom next to the power cord Test Procedure 1 Unplug the grinder 2 Remove cap and fuse fr
7. If no press Func NOTE Pressing Func will return to idle display Use present weight as tare for calibration If yes press Display will read 1 then press Func If no press Func To calibrate by grinding coffee press display will then read 1 then press Func Enter desired calibration weight using and buttons Then press start switch on grinder Display changes to 0 00 and shows increasing weight as coffee is ground When grinding stops and 7 has reappeared in left corner of the display Push Func to advance to Function 8 before removing funnel Weigh sample grind and enter actual weight onto the display by pressing or if necessary To abort and retain old calibration enter 0 00 Press Func when complete Enter new password To keep same password press Func to change pass word press or press function to enter new password and return to function 0 normal operation NOTE Display shows when taring Do not disturb while this is shown NOTE WDG2 Models can be converted from weight based settings to timed settings by pressing the and buttons for 10 seconds Repeating the process will convert back to weight based settings RANGE MIN MAX 0000 9999 0 00 9 99 0 00 9 99 1 Yes 1 1 Grind 3 00 16 00 0 00 16 00 0000 9999 10854 030300 TROUBLESHOOTING A troubleshooting guide is provided to suggest probable causes and remedies
8. OFF ON START SWITCH YEL TO SELECTOR SWITCH GRN TO OPTIONAL MULTISET SWITCH TAN TO OPTIONAL INTERFACE CONNECTOR GRY TO OPTIONAL INTERFACE CONNECTOR BLK TO FUSE HOLDER WHI TO POWER CORD VIO TO SELECTOR SWITCH RED TO MOTOR CIRCUIT BOARD Prior to S N DG00002660 WHI TO MOTOR CIRCUIT BOARD S N 0600002660 UP ORA TO OFF ON START SWITCH ORA TO OFF ON START SWITCH TAN TO INTERFACE CONNECTOR GRY TO INTERFACE CONNECTOR BLK TO GRINDING LED PNK TO INTERFACE CONNECTOR Weigh Control Board WDG 2 Test Procedure 1 Disconnect grinder from the power source 2 Slide the weigh control board with wires con nected from housing 3 Place the hopper selector switch in the left posi tion 4 Disconnect eight pin plug J4 from weigh control board 5 Check the voltage between J4 1 and J4 2 witha voltmeter Connect the grinder to the power source The indication must be 120 volts AC 6 Disconect grinder from the power source If voltage is present as described proceed to 7 If voltage is not present as described refer to the wir ing diagram and check grinder wiring harnes
9. UIREMENTS This grinder has an attached cordset and requires 2 wire grounded service rated 120 volts ac 15 amp single phase 60 Hz OPERATING CONTROLS Off On Start Switch OFF upper position Switching to this position stops all operation of the grinder ON middle position The switch will return to this position after a grind cycle has begun and will remain in this position after grinding has ceased START lower momentary position Pressing the switch to this position and releasing initiates a grind cycle Hopper Selector Switch LEFT Switching to this position allows beans to be ground from the left hopper RIGHT Switching to this position allows beans to be ground from the right hopper Dispense Timer DG 2 The dispense timer controls the amount of beans that will be ground a cycle The timer can be adjusted to dispense a different amount from each hopper The scale is from 0 1 to 60 0 seconds Refer to the Adjustments section for timer setting chart See page 7 Increase left momentary push button DISPENSE TIME Seconds Pressing this button will increase the dispense interval on the timer while the readout is displayed The interval will change slowly for the first second s DSRLAY S indication then speed up for the next fifteen second s indication and increase very fast after that until it reaches the limit on the scale mier DISPLAY center momentary push button Pressing this
10. VOLTS AC TAN CONNECTOR 2 WIRE SINGLE PHASE 60 HZ 21 10854 030300
11. button will display the current timer readout The timer can only be adjusted while the readout is displayed The indication on the display h will last for five minutes WARNING A UNPLUG GRINDER BEFORE REMOVING HAZARDOUS VOLTAGE Decrease right momentary push button Pressing this button will decrease the dispense interval on the timer while the readout is displayed The interval will change slowly for the first second s indication then speed up for the next fifteen second s indication and increase very fast after that until it reaches the limit on the scale 4 10854 030300 DG 2 INITIAL SET UP 10 11 12 13 WARNING Unplug grinder before removal of any panel Read NOTICE attached to upper front inspection panel Remove upper front inspection panel located below control switches and the rear panel Remove shipping bracket materials and discard Reinstall upper front inspection panel and rear panel Open the top lid s Clear all foreign objects and shipping material from the hopper compartments and the entrance to the grind chambers Remove the lower front inspection panel Plug in the grinder Select either the left or right hopper with the selector switch Do not press the start switch The dispense timer panel readout will indicate the present timer setting in seconds and will remain displayed for five minutes Increase or decrease the timer setting to obtain the desired amount of cof fe
12. ce Timer for testing pro cedures See page 16 Begin each grind cycle by visually inspect ing the hoppers for ample supplies of whole bean coffee Foreign materials must not block the open ings at the bottom of the hoppers A Unplug the grinder Wait a few sec onds and plug it in again B Refer to Service Timer for testing pro cedures See page 16 Refer to the Adjustments section See page 7 Refer to Service Motor Circuit Assem bly replacement procedures See page 16 Refer to the Adjustments section See page 7 Switch must be in the ON middle position Refer to Service Fan See page 20 10854 030300 TROUBLESHOOTING cont Problem Probable Cause LED will not come on when motor is 1 No power running 2 Faulty LED Weigh control assembly leaking oil WDG 2 Incorrect amount of coffee WDG 2 WDG 2 DIGITAL DISPLAY CONTROL FAULT CODES Remedy Check timer and for loose connections Refer to Service LED See page 21 Replace See removal and replacement page 23 Check function list on setting the weight to be ground page 8 if settings are ok replace weigh control assembly See page 23 for removal and replacement NOTE If the grinder stops or fails to start the green L E D should be flashing The number of flashes corresponds to the fault code The fault will also show on the digital display FAULT PROBLEM 1 Grinder on for three seconds without a weight
13. check for continuity If continuity is now present the motor overload is reset If motor over load does not reset replace motor 10 Set an ohm meter to read at least 10 ohms Connect leads from ohm meter to the black and red wires from the left or right motor The ohm reading should be approximately 10 ohms Rotate the motor shaft approxi mately 1 8 turn through one full rotation If ohm readings are consistent motor wind ings are good If reading vary more than 1 ohm replace motor Removal and Replacement 1 Disconnect red black and blue wires from the motor to be removed from the motor circuit as sembly 1 Loosen the two 10 32 slotted head screws 2 attaching motor circuit assembly 1 to motor mounting bracket 5 Remove motor circuit assembly 1 with wires from harness and the opposite motor connected Right Motor Disconnect blue wire on motor from blue wire on hopper selector switch 4 Left Motor Disconnect blue wire on motor from white blue wire on hopper selector switch 4 Using a 7 16 socket extension and rachet re move two 1 4 20 hex head capscrews and lockwashers 3 attaching front of motor to front of mounting bracket 5 Remove two 10 32 slotted hex head screws 2 Lift motor out of mounting bracket 5 and re move through the rear of grinder with hopper collar and discharge chute assembly attached Remove four 10 24 slotted hex head screws attaching discharge chute to motor Remo
14. d head screws The lower front inspection panel is attached with four 6 32 slotted head screws The rear panel is attached with eight 8 32 slot ted head screws NOTE Disconnect fan motor leads from main wiring harness The lid is attached to hopper divider with four 6 32 slotted head screws Hopper dividers attached to hopper and housing with two 6 32 slotted head screws Remove lid and hopper divider as an assem bly CONTENTS A DD 20 20 Hopper Selector Switch 13 LED a Goes ases 21 MOIDIS 2 14 Motor Circuit Assembly 16 Off On Start S WIBGDE s siis res 13 16 Weigh Control Board 18 Weigh Control Assembly 21 10854 030300 SERVICE cont The hopper is attached with ten 8 32 x 25 slot ted head locking screws Remove hopper by lifting up and swing out the rear of the grinder to avoid scratching of windows Off On Start Switch The Off On Start switch is located to the left side on the front of the housing above the upper front inspection panel Test Procedure 1 Unplug the grinder 2 Remove all wires from the switch terminals 3 Check for continuity across the terminals on the right side of the switch when i
15. e for the hopper selected by pressing the appropriate button or Repeat steps 9 thru 11 for the other hopper The display will go out on its own Reinstall lower front inspection panel Fill the hopper compartments with whole bean coffee Capacity 6 pounds each The grinder is now ready for use WDG 2 INITIAL SET UP 10 11 WARNING Unplug grinder before removal of any panel Read NOTICE attached to the upper front inspection panel Remove upper front inspection panel located below control switches and the rear panel Remove shipping bracket materials and discard Reinstall upper front inspection panel and rear panel Open the top lid s Clear all foreign objects and shipping material from the hopper compartments and the entrance to the grind chambers Remove the four screws securing the lower front inspection panel and care fully pull out far enough to view and operate the digital control display assembly Plug in the grinder Select either the left or right hopper with the selector switch Do not press the start switch The digital control display assembly screen displays selected weight when idle When grinding display resets to 0 00 and shows increasing weight Display shows final weight for ten seconds and returns to selected weight Use or buttons and left or right hopper selector switch to set selected weights 50 07 minimum 16 07 maximum NOTE Refer to function list on page 8 for recalibration o
16. f weigh control assembly if necessary 10854 030300 SPECIAL SET UP FOR FLAVORED COFFEE BEANS 1 2 WARNING Unplug grinder before removal of any panel Select the hopper to be used for flavored coffee beans Remove upper front inspection panel located below control switches Locate dechaffer blade lever for hopper s se lected in step 2 Rotate lever clockwise approximately 90 Remove clip s from bag inside of grinder hous ing and clip to the right of the lever This will hold the dechaffer open Reinstall upper front inspection panel 10854 030300 10854 030300 CLEANING EXTERIOR SURFACES The use of a damp cloth rinsed in any mild nonabrasive liquid detergent is recommended for cleaning all surfaces on Bunn O Matic equipment Care should be taken not to scratch the hopper or windows with any abrasive material Regular cleaning will keep your grinder looking new for years GRIND CHAMBER 1 2 3 4 10 Reinstall dispense chute cover 12 13 WARNING Unplug grinder before removal of any panel or grind chamber housing parts Empty all beans from both hoppers Remove upper front inspection panel located below control switches Remove the two nuts holding dispense chute cover Carefully wipe inside surface of dispense chute and cover with a dry clean cloth Select a grind chamber to clean first Each gri
17. grind from the factory setting WARRANTY Bunn O Matic Corp Bunn warrants the equipment manufactured by it to be commercially free from defects in material and workmanship existing at the time of manufacture and appearing within one year from the date of installation In addition 1 Bunn warrants electronic circuit and or control boards to be commercially free from defects in material and workmanship for two years from the date of installation 2 Bunn warrants the compressor on refrigeration equipment to be commercially free from defects in mate rial and workmanship for two years from the date of installation 3 Bunn warrants that the grinding burrs on coffee grinding equipment will grind coffee to meet original factory screen sieve analysis for three years from date of installation or for 30 000 pounds of coffee whichever comes first This warranty does not apply to any equipment component or part that was not manufactured by Bunn or that in Bunn s judgement has been affected by misuse neglect alteration improper installation or operation improper maintenance or repair damage or casualty THE FOREGOING WARRANTY IS EXCLUSIVE AND IS IN LIEU OF ANY OTHER WARRANTY WRITTEN OR ORAL EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF EITHER MER CHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE The agents dealers or employees of Bunn are not authorized to make modifications to this warranty or to make add
18. he open ing 3 Push the new switch into the opening and spread the clips to retain the switch in the housing 4 Refer to the following illustration when re necting the wires REAR VIEW 1 Motor Circuit Assembly 2 Motor amp Circuit Assembly Mounting Screws 3 Motor Mounting Screws 4 Hopper Selector Switch 5 Motor Mounting Bracket The motors are located in the center part of the housing just below the hopper 16 10854 030300 SERVICE cont Motor cont Test Procedure 1 2 3 4 Disconnect grinder from the power supply Remove upper front inspection panel Remove the two 1 4 20 screws A holding the front cover B Remove load disc C from burr auger rotor as sembly D Remove burr auger rotor spring assembly D from the burr housing H Remove rear panel Disconnect the red black and blue wires from the left or right motor to the motor circuit as sembly 1 A Left Motor Disconnect blue wire on the left motor from the blue wire to the hopper selector switch B Right Motor Disconnect the blue wire on the right motor from the white blue wire to the hopper selector switch Connect leads of an ohm meter to the blue wires from the left or right motor Check for continuity If continuity is present the motor overload is good If continuity is not present press the red RESET but ton Listen carefully for a click This resets the mo tor overload Re
19. imer with wires connected from housing 3 Place the hopper selector switch in the left posi tion 4 Disconnect eight pin plug J4 from timer board 5 Check the voltage between J4 1 and J4 2 with a voltmeter Connect the grinder to the power source The indication must be 120 volts AC 6 Disconnect grinder from the power source If voltage is present as described proceed to 77 If voltage is not present as described refer to the wiring diagram and check grinder wiring harness 7 Check the voltage between J4 2 and J4 6 with a voltmeter when the OFF ON START switch is in the ON position Connect the grinder to the power source The indication must be 120 volts AC 8 Disconnect grinder from the power source If voltage is present as described proceed to 79 If voltage is not present as described refer to the wiring diagram and check the grinder wiring harness 9 Grinders prior to S N DG00002660 Check the voltage between J4 3 and J4 5 with a voltmeter set to read DC voltage when the OFF ON START switch is in the START po sition The indication must be 110 volts DC mini mum Grinders S N DG00002660 UP Check the voltage between J4 3 and J4 5 with a voltmeter when the OFF ON START is in the START position The indication must be 120 volts AC 10 Disconnect grinder from the power source If voltage is present as described proceed to 711 If voltage is not present as described replace
20. increase 2 4 Grinder motor shutting off in middle of grind PROBABLE CAUSE Selected hopper ran out of whole bean coffee Foreign objects in motor grinding burrs causing motor to shut off Scale cannot find tare due to excess vibration Power or hopper selector switch changed during grind 13 REMEDY Fill selected hopper with whole bean coffee Clear motor gringing burs of all foreign objects and press the red RESET button on rear of motor Move grinder to solid vibration free counter Do not change switches during grind 10854 030300 SERVICE This section provides procedures for testing and replacing various major components used in this grinder should service become necessary Refer to Troubleshooting for assistance in determining the cause of any problem WARNING Inspection testing and repair of electri cal equipment should be performed only by qualified service personnel The grinder should be unplugged when servicing except when electrical tests are re quired and the test procedure specifically states to plug in the grinder Component Access WARNING Unplug the grinder before the removal of any panel or the replacement of any component All components are accessible by the removal of the upper and lower front inspection panels hop per assembly and rear panel The upper front inspection panel is attached with four 8 32 slotte
21. ing bracket and weigh control board 2 from the grinder Remove the two 10 32 slotted head screws securing weigh control mounting bracket 3 to the base of the grinder and the two 10 32 keps nuts securing the weigh control mounting bracket 3 to the rear of the grinder housing Slide weigh control mounting bracket 3 from grinder housing far enough to have access to weigh control assembly 4 Holding pivot arm w overload assembly 5 up remove the four 8 32 pan head screws secur ing weigh control assembly 4 Remove and dis card weigh control assembly 4 Holding pivot arm w overload assembly 5 up install the new weigh control assembly 4 to the mounting bracket 3 using four 8 32 pan head screws Slide weigh control assembly mounting bracket 3 on to the two studs on the rear of the grinder housing and secure with two 10 32 keps nuts NOTE Carefully guide all wires while installing the 14 weigh mechanism The funnel tab 7 on the fun nel rails mounting bracket 6 must be in clear ance slot 8 in the grinder housing and must move freely up and down Secure weigh control assembly mounting bracket 3 to grinder base with two 10 32 slotted head screws Slide the weigh control bracket and weigh con trol board 2 into the weigh control mounting bracket 3 far enough to reconnect the eight and ten pin connectors from the main wiring harness and the four pin connector from the weigh con trol assembly Co
22. itch for testing procedures See page 13 Refer to Service Timer for testing pro cedures See page 16 Refer to Service Weight Control Board for testing procedures See page 18 Remove Grinder rear cover Press the red Reset button one located on rear of each motor Listen carefully for a click This resets the motor protec tion circuit and indicates that an over load may have been encountered by the motor An overload can occur when something other than coffee is inserted into the hopper for grinding Refer to Service Motors for disassembly pro cedures See page 14 10854 030300 TROUBLESHOOTING cont Problem Grinder will not start cont Grinder will not shut off Grinder starts but will not dispense from either hopper Timer will not display or displays incorrectly Incorrect amount of coffee DG 2 Incorrect coffee grind dispensed Cooling fan not running Probable Cause 5 Motors 6 Fuse 1 Off On Start switch 2 Timer 1 Hoppers 2 Blockage of hoppers 1 Timer 1 Volume adjustment 2 Motor circuit assembly 1 Burr adjustment 1 Off On Start switch 2 Fan Remedy Refer to Service Motors for testing pro cedures See page 14 Refer to Service Fuse for testing pro cedures See page 20 A Place the switch in the OFF upper position B Refer to Service Off On Start Switch for testing procedures See page 13 Refer to Servi
23. itional warranties that are binding on Bunn Accordingly statements by such individuals whether oral or written do not constitute warranties and should not be relied upon The Buyer shall give Bunn prompt notice of any claim to be made under this warranty by telephone at 217 529 6601 or by writing to Post Office Box 3227 Springfield Illinois 62708 3227 If requested by Bunn the Buyer shall ship the defective equipment prepaid to an authorized Bunn service location If Bunn determines in its sole discretion that the equipment does not conform to the warranty Bunn shall repair the equipment with no charge for parts during the warranty period and no charge for labor by a Bunn Authorized Service Representative during the warranty period If Bunn determines that repair is not feasible Bunn shall at its sole option replace the equipment or refund the purchase price for the equipment THE BUYER S REMEDY AGAINST BUNN FOR THE BREACH OF ANY OBLIGATION ARISING OUT OF THE SALE OF THIS EQUIPMENT WHETHER DERIVED FROM WARRANTY OR OTHERWISE SHALL BE LIMITED AS SPECIFIED HEREIN TO REPAIR OR AT BUNN S SOLE OPTION REPLACEMENT OR REFUND In no event shall Bunn be liable for any other damage or loss including but not limited to lost profits lost sales loss of use of equipment claims of Buyer s customers cost of capital cost of down time cost of substi tute equipment facilities or services or any other special incidental or consequential da
24. mages 2 10854 030300 USER NOTICES Carefully read and follow all notices on the grinder and in this manual They were written for your protection All notices on the grinder are to be kept in good condition Replace any unreadable or damaged labels A CAUTION PERSONAL INJURY HAZARD KEEP FINGERS AND FOREIGN OBJECTS OUT OF HOPPER OR CHUTE OPENING 05876 0000 For connection to Bunn O Matic Coffee Brewer Models Dual OT Single amp System III only 24 volt N E C Class 2 circuit only 24237 0000 AWARNING Use only on a properly protected circuit capable of the rated load Electrically ground the chassis Follow national local electrical codes Do not use near combustibles An extension cord when used must be shorter than 20 feet if 16 gage 3 conductor wire or shorter than 10 feet if 18 gage 3 conductor wire FAILURE TO COMPLY RISKS EQUIPMENT DAMAGE FIRE OR SHOCK HAZARD READ THE ENTIRE OPERATING MANUAL INCLUDING THE LIMIT OF WARRANTY AND LIABILITY BEFORE BUYING OR USING THIS PRODUCT 20545 0000 7 90 O 1990 Bunn O Matic Corporation 20545 0000 DISPENSE TIME Seconds DISPLAY Increase Y Decrease 4 Readout will be displayed for 5 minutes Timer can only be adjusted while readout is displayed WARNING HAZARDOUS VOLTAGE AUR UNPLUG GRINDER BEFORE REMOVING 05942 0000 06 2 ELECTRICAL REQ
25. nd chamber should be disassembled cleaned and reassembled before cleaning the opposite side Remove the two screws holding front cover to burr housing Carefully remove burr housing front cover Clean the inside surface with a dry stiff nonmetallic bristle brush and wipe with a dry clean cloth Carefully remove rotor button rotor brass bushing and steel washer from grinder Clean all parts with a dry stiff nonmetallic bristle brush and wipe with a dry clean cloth Clean the grind chamber with a dry stiff nonmetallic bristle brush and wipe with a dry clean cloth Use a small screw driver to dislodge coffee packed in the discharge chute at the base of the grind chamber and wipe Clean Use care not to damage dechaffer blade Reinstall steel washer brass bushing flanged end first rotor rotor button and front cover to burr housing Repeat steps 6 through 9 on remaining grind chamber Reinstall upper front inspection panel Refer to adjustments section below to vary the grind dispensed from each grind chamber COFFEE GRINDING 1 Select either left or right hopper with selector switch and visually inspect the desired hopper for an ample supply of whole bean coffee Place a paper filter into the brew funnel The filter must not be folded over or tilted to one side Insert the funnel into the funnel rails and push until it stops Momentarily press off on start switch to the START lower position and release The grinding action will stop
26. nnect the wiring Refer to the illustration on page 19 when reat taching the connectors NOTE Inspect for pinched wires 15 25 Slide weigh control bracket and weigh control board 2 the rest of the way into the weigh con trol mounting bracket 3 and secure with one 6 32 truss head screw Reinstall lower front inspection panel with digi tal control display assembly attached using four 6 32 truss head screws Connect the grinder to the power source and fol low the function list on page 8 for information on setting the weight to be ground 10854 030300 WIRING DIAGRAMS SCHEMATIC WIRING DIAGRAM DG2 L1 N GRN OFF ON 10 AMP ges START SW ETT BLK i PUR A1 WHI nA rl J4 8 Mel Ana RED OPTIONAL MULT SET SW MF P ml L7 10 Uer 1 BREWER BLK PNK pe GRY INTERFACE TAN Ii BLU CONNECTOR S B BREWER GRY INTERFACE PNK WHI RED BLK CONNECTOR TAN WHI BLK 120 VOLTS AC 2 WIRE WHI BLU SINGLE PHASE 60 HZ 26 10854 030300 WIRING DIAGRAMS SCHEMATIC WIRING DIAGRAM WDG2 L1 N GRN OFF ON T Eu ORA CIRCUIT BOARD J4 8 J1 1 OPTIONAL MULTI SET SW GRINDING BLK PNK m1 GRY GRY ZY BLU BLU EEE eere J1 1 CONTROL ASSY WHI BLU WHI RED_ BLK WHI BLK aes J1 6 OPTIONAL PNK BREWER TAN INTERFACE CONNECTOR DUM GRY BREWER PNK INTERFACE 120
27. om fuse holder 3 Remove fuse from the cap 4 Check for continuity through the fuse If continuity is present as described reinstall the fuse the fuse is operating properly If continuity is not present as described replace the fuse Removal and Replacement 1 Remove cap from fuse holder 2 Remove fuse from fuse holder inspect if blown discard 3 Install a new SC 10 x 312 fuse in fuse holder 4 Reinstall fuse holder cap 10854 030300 SERVICE cont L E D Location The L E D is located on the front of the grinder just above hopper selector switch Test Procedure 1 Unplug the grinder 2 Remove the wire nuts from both sets of wires 3 With a voltmeter set to read DC volts Attach the positive lead to the black and pink wires and the negative lead to the gray wires 4 Connect grinder to the power supply 5 Initiate a grind cycle Voltage should be approxi mately 2 volts DC If the voltage is present as described the L E D is operating properly If the voltage is not present as described proceed to 6 6 After initiating a grind cycle in step 5 the volt age was approximately 5 volts DC Replace the L E D If the voltage is approximately 0 volts re fer to wiring diagrams and check the wiring har ness Removal and Replacement 1 Remove upper front inspection panel 2 Disconnect PNK and GRY wires from L E D 3 Using a 5 16 open end wrench remove n
28. right desired hopper Momentarily press the DISPLAY center button The display will indicate the current timer setting and will allow adjustment Press the or buttons as required to obtain the desired grind time The interval will change slowly for the first second s indication then speed up for the next fifteen second s indication and increase very fast after that until it reaches the limit on the scale Set the timer for the desired amount of coffee to be ground Verify the setting by weighing a few samples Use the chart on page 10 as an approximate guide only 9 10854 030300 Coffee Weight Timer Settings Approx 4 0 seconds per ounce Medium Roast Drip Grind Approx 5 5 seconds per ounce Dark Roast Drip Grind Time will vary depending on bean density amp grind size Check samples by weight DIGITAL CONTROL DISPLAY ASSEMBLY FUNCTION LIST WDG 2 FUNCTION NO FUNCTION 10 Place funnel with filter into rails press Func button to advance to Function One When entering this function load sensor is tared To gain access to remaining functions press or button once to enter password 0 Display will read 0 now press Func Set weight offset right grinder Press or to adjust if necessary Press Func Set weight offset left grinder Press or to adjust if necessary Press Func Enter calibration mode If yes press display will read 1 then press Func
29. s 7 Check the voltage between the J4 2 and J4 6 Location with a voltmeter when the OFF ON START Switch is in the ON position Connect grinder to The weigh control board is located on the grinder base the power source The indication must be 120 behind the lower front inspection panel volts AC 20 10854 030300 SERVICE cont Weigh Control Board WDG 2 cont 8 Disconnect grinder from the power source If voltage is present as described proceed to 9 If voltage is not present as described refer to the wir ing diagram and check the grinder wiring harness 9 Check the voltage between J4 3 and J4 5 with a voltmeter when the OFF ON START is in the START position Connect grinder to the power source The indication must be 120 volts AC 10 Disconnect grinder from the power source If voltage is present as described proceed to 11 If voltage is not present as described replace weigh control board 11 Reconnect the wires 12 Place the hopper selector in the right position 13 Repeat steps 74 thru 10 Grinders with One or Two Brewer Optional Interface 1 Set the brewer selector switch on one third batch with grinder OFF ON START switch in the ON position 2 Selectthe two third s batch if the readout is not different then adjust the settings and return se lector switch to one third batch The readout should now be different 3 Select full batch if the readout is not different then adjust
30. t is held in the lower START position Continuity must not be present across these terminals in the center or upper position If continuity is present as described proceed to 4 If continuity is not present as described replace the switch 4 Check for continuity across the terminals on the left side of the switch when it is in the center ON position Continuity must not be present in the upper OFF position If continuity is present as described reconnect the wires the switch is operating properly If continuity is not present as described replace the switch Removal and Replacement 1 Remove all wires from the switch terminals 2 Compress the clips inside the front of the hous ing and gently push the switch through the open ing 3 Push the new switch into the opening and spread the clips to retain the switch in the housing 4 Refer to the following illustration when recon necting the wires RED TO J1 1 ORA TO J4 7 PNK TO SELECTOR SWITCH ORA TO J4 6 WHI RED TO FAN REAR VIEW Hopper Selector Switch The Hopper Selector Switch is located in the center on the front of the housing above the upper front inspection panel 15 10854 030300 SERVICE cont Hopper Selector Switch cont PNK TO OPTIONAL MULTISET SWITCH PNK TO OFF ON START SWITCH Test Procedure
31. the settings and return selector switch to two third s batch The readout should be dif ferent 4 Repeat steps 1 thru 3 for the opposite side NOTE Each brew selection has its own readout If readouts do not differ with each brew selection after adjusting settings check interface cable If interface cable is ok replace weigh control board Removal and Replacement 1 Separate the grinder wiring harness connectors from the weigh control board 2 Refer to the illustration below when re attach ing the connectors 3 Refer to the Adjustments page 7 section to re set the volume dispensed RED TO OFF ON START SWITCH YEL TO SELECTOR SWITCH GRN TO OPTIONAL MULTISET SWITCH TAN TO OPTIONAL INTERFACE CONNECTOR GRY TO OPTIONAL INTERFACE CONNECTOR VIO TO SELECTOR SWITCH WHI TO POWER CORD BLK TO FUSE HOLDER WHI TO MOTOR CIRCUIT BOARD ORA TO OFF ON START SWITCH Ow 7 DIGITAL CONTROL DISPLAY ASSEMBLY CORD CONNECTION GRY TO WEIGH CONTROL ASSEMBLY BLK TO WEIGH CONTROL ASSEMBLY ORA TO OFF ON START SWITCH 5 TAN INTERFACE CONNECTOR GRY TO INTERFACE CONNECTOR BLK TO GRINDING LED PNK TO INTERFACE CONNECTOR RE
32. timer and motor circuit board with part number 25725 1000 0n grinders prior to S N DG00002660 also order main wiring harness 25762 0001 11 Reconnect the wires 12 Place the hopper selector in the right position 13 Repeat steps 4 thru 10 Grinders with One or Two Brewer Optional Interface 1 Setthe brewer selector switch on one third batch with grinder OFF ON START switch in the ON position 2 Select the two third s batch if the readout is not different then adjust the settings and return se lector switch to one third batch The readout should now be different 3 Select full batch if the readout is not different then adjust the settings and return selector switch to two third s batch The readout should be dif ferent 4 Repeat steps 1 thru 3 for the opposite side NOTE Each brew selection has its own readout If readouts do not differ with each brew selection after adjusting settings check interface cable If interface cable is ok replace timer and motor circuit board with part number 25725 1000 On grinders prior to S N DG00002660 also order main wiring harness part number 25762 0001 Removal and Replacement 1 Separate the grinder wiring harness connectors from the timer circuit board 2 Refer to the illustration on next page when reat taching the connectors 3 Refer to the Adjustments page 7 section to re set the volume dispensed 19 10854 030300 SERVICE cont Timer DG 2 cont RED TO
33. urr housing H Remove and inspect burr for wear Replace if excessively worn or damaged 6 Inspect the grind chamber and remove any for eign materials The burrs will not properly seat in the chamber if any material or coffee particles remain 7 Reinstall the stationary burr G washer F bushing E burr auger rotor spring assembly D load disc C and burr housing front cover B with adjusting screw and nut to the burr housing H 8 Refer to Adjustments section page 7 to vary the grind dispensed Motor Circuit Assembly The motor circuit assembly is located on the rear of motor mounting bracket Test Procedure 1 motor circuit assembly is a line filter for motor electrical noise 2 Ifthe timer settings are erratic or change replace the motor circuit assembly board Removal and Replacement 1 Remove all wires 2 Loosen the two 710 32 slotted hex head screw and lift motor circuit assembly off 3 Install new motor circuit assembly between head of screws and external tooth lockwashers Tighten screws 4 Refer to Wiring Diagram pages 24 amp 25 and reinstall wires Timer DG 2 The timer is located on the grinder base behind the lower front inspection panel 10854 030300 SERVICE cont Timer DG 2 cont Test Procedure 1 Disconnect grinder from the power source 2 Slide t
34. ut on back of front housing securing L E D Remove L E D and discard 4 Install new L E D through front of grinder hous ing and secure with nut 5 Connect PNK and GRY wires from L E D Refer to wiring diagram on pages 24 amp 25 Weigh Control Assembly WDG 2 The weigh control assembly is located behind the lower front inspection panel just under and behind the funnel rails 10854 030300 SERVICE cont Weigh Control Assembly WDG 2 cont 1 Front Inspection Panel 5 Pivot Arm 2 Weigh Control Board and Mounting Bracket 6 Funnel Rails Mounting Bracket 3 Weigh Control Mounting Bracket 7 Funnel Tab 4 Weigh Control Assembly 8 Slot in Housing Assembly 24 10854 030300 SERVICE cont Weigh Control Assembly WDG 2 cont Removal and Replacement 1 2 e 10 11 Disconnect grinder from the power source Remove the four 6 32 truss head screws se curing lower front inspection panel 1 Remove panel with digital control display assembly at tached Remove the one 6 32 truss head screw secur ing the weigh control board mounting bracket 2 to the weigh assembly mounting bracket 3 Slide weigh control board mounting bracket and control board 2 out of weigh assembly mount ing bracket 3 far enough so the connectors on the grinders main wiring harness and the con nector on the weight assembly leads can be dis connected Disconnect connectors Remove weigh control board mount
35. ve dis charge chute Set discharge chute and screws aside for reassembly On new motor assembly with hopper collar in stall discharge chute assembly using four 10 24 slotted hex head screws Mount new motor hopper collar and discharge chute assembly on mounting bracket using two 1 4 20 hex head capscrews and lockwashers 3 and two 10 32 slotted hex head screws 2 and one external tooth lockwasher Install motor circuit assembly 1 between head of the two 10 32 slotted hex head screws 2 and external tooth lockwashers Tighten screws 2 Refer to wiring diagram pages 24 amp 25 and connect wires from motor to motor circuit as sembly 1 and hopper selector switch 4 10854 030300 SERVICE cont Motor cont Removal and Replacement GRIND CHAMBER 1 Remove the two 1 4 20 screws A holding the front cover B to the burr housing H Carefully remove the burr housing front cover with adjust ing screw and nut Inspect adjusting screw to see if worn Replace if excessively worn or damaged 2 Remove load disc C from burr auger rotor spring assembly D Inspect disc to see if worn Replace if excessively worn or damaged 3 Carefully remove burr auger rotor spring assem bly D from burr housing H Inspect burr for wear Replace if excessively worn or damaged 4 Remove bushing and washer F from motor shaft 5 Remove the two 1 4 20 screws attaching sta tionary burr G to b
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