BUNN ® SYSTEM III OPERATING & SERVICE MANUAL BUNN-O-MATIC CORPORATION POST OFFICE BOX 3227 SPRINGFIELD, ILLINOIS 62708-3227 PHONE: (217) 529-6601 FAX: (217) 529-6644 27362.
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.
USER NOTICES Carefully read and follow all notices in this manual and on the equipment. The notices on this brewer should be kept in good condition. Replace any unreadable or damaged labels. 12364.0000 10044.0000 ! WARNING HOT WATER 20201.5600 00831.0000 03408.0000 00656.0000 03409.
ELECTRICAL REQUIREMENTS CAUTION - The brewer must be disconnected from the power source until specified in Initial Set-Up. L2RED WHITE NEUTRAL L2 RED 120V.A.C. 208 or 240V.A.C. L1 BLACK 200 OR 240V.A.C. 120V.A.C. BLACK P2185 P1841 "A" & "B" models require 2-wire, grounded service rated 200 volts ac or 240 volts ac, 20 amp, single phase, 50 Hz. Requires 3-wire, grounded service rated 120/208 volts or 120/240 volts ac, 20 amp, single phase, 60 Hz.
INITIAL SET-UP CAUTION – The brewer must be disconnected from the power source throughout the initial set-up, except when specified in the instructions. 1. Remove the front panel beneath the sprayhead. Models with digital brewer control assembly: Place the tank heater toggle switch at the bottom left of the control assembly in the "OFF" position. Models with electro/mechanical thermostats: Rotate the control thermostat knob fully counterclockwise to the "OFF" position. 2.
ADJUSTING BREW VOLUMES (cont.) To decrease a batch size. Press and release the START or BREW switch once for every two-second interval to be removed from the total brew time period; then immediately press and hold down the START or BREW switch until three clicks are heard. Release the switch. (Failure to release the switch within two seconds after the third click causes the volume setting to be aborted and previous volume setting will remain in memory).
TROUBLESHOOTING A troubleshooting guide is provided to suggest probable causes and remedies for the most likely problems encountered. If the problem remains after exhausting the troubleshooting steps, contact the Bunn-O-Matic Technical Service Department. • • • • • • • WARNING • • • • Inspection, testing, and repair of electrical equipment should be performed only by qualified service personnel. All electronic components have 120 - 240 volt ac and low voltage dc potential on their terminals.
TROUBLESHOOTING (cont.) Problem Probable Cause Remedy Brew cycle will not start (cont.) 3. ON/OFF switch Refer to Service - ON/OFF switch for testing procedures. See page 28 4. Start switch Refer to Service - Start switch for testing procedures. See page 32 5. Timer Refer to Service - Timer for testing procedures. See page 34 or 35 6. Dispense Valve Refer to Service - Dispense valve for testing procedures. See page 21 7.
TROUBLESHOOTING (cont.) Problem Probable Cause Remedy Automatic refill will not operate 6. Solenoid Valve (cont.) Refer to Service - Solenoid valve for testing procedures. See page 30 Beverage level will not adjust (Selec- 1. Selector switch tor switch in any position) Refer to Service - Selector switch for testing procedures. See page 16 Water flows into tank continuously (ON/OFF Switch "OFF") Refer to Service - Level control board for testing procedures. See page 25 Water from tank is not hot 1.
TROUBLESHOOTING (cont.) Problem Probable Cause Remedy Water from tank is not hot (cont.) 5. Triac assembly (DBC) Refer to Service - Digital brewer control for testing procedures. See page 22 Server warmer is not hot. 1. ON/OFF switch Refer to Service - ON/OFF switch for testing procedures. See page 28 2. Warmer element Refer to Service - Warmer element for testing procedures. See page 37 1. (A) Control thermostat (Electro/ mechanical) Refer to Service - Control thermostat for testing procedures.
TROUBLESHOOTING (cont.) Problem Probable Cause Remedy Inconsistent beverage level in server. (cont.) 3. Dispense valve Refer to Service - Dispense valve for testing procedures. See page 21 Consistently high or low beverage level in server. 1. (A) Time adjustment (Electro/ Refer to Service - Brew Timer for mechanical) testing and adjustment procedures. See pages 34 or 35 (B) DBC volume adjustment Refer to Service - Digital brewer control for testing procedures.
TROUBLESHOOTING (cont.) Problem Probable Cause Remedy Weak beverage (cont.) 3. Sprayhead B.O.M. sprayhead #01082.0002 should be used to properly wet the bed of ground coffee in the funnel. 4. Funnel loading The BUNN® paper filter should be centered in the funnel and the bed of ground coffee leveled by gentle shaking. 5. Water temperature Empty the server, remove its cover, and place the server on the warmer.
TROUBLESHOOTING (cont.) Problem Probable Cause Remedy Cannot access the DBC 1. Digital brewer control Refer to Service - Digital brewer control for testing procedures. See page 22 step 7 DBC display is blank 1. Digital brewer control Refer to Service - Digital brewer control for testing procedures.
SERVICE This section provides procedures for testing and replacing various major components used in this brewer should service become necessary. Refer to Troubleshooting for assistance in determining the cause of any problem. WARNING - Inspection, testing, and repair of electrical equipment should be performed only by qualified service personnel. The brewer should be unplugged when servicing, except when electrical tests are required and the test procedure specifically states to plug in the brewer.
SERVICE (cont.) 4. Disconnect the white/green wire and white/violet wire. Check for continuity across the bypass valve coil terminals. BYPASS VALVE LOCK If continuity is present as described, reconnect the white/green and white/violet wires to the bypass valve and proceed to #5. If continuity is not present as described, replace the bypass valve. LOCK SET SET 5. Check the bypass valve for coil action. Connect brewer to the power source.
5. Reattach the connector to the brew timer circuit board or DBC connector. SERVICE (cont.) BREW SELECTOR SWITCH Grinder Interface: 6. Disconnect pink, gray and tan wires on the selector switch from the pink, gray and tan wires on the interface socket. 7. Check for continuity across the pink wire and the tan wire on the selector switch when the switch is in the 1 gallon position. Continuity must not be present in any other position. 8.
SERVICE (cont.) BREW SELECTOR SWITCH (cont.) 7. Install the knob so that the arrow lines up in the 2 gallon position when the switch is turned to the full right position. 8. Reattach the connector to the brew timer circuit board or DBC 9. Refer to Fig. 5 when reconnecting the wires.
SERVICE (cont.) CONTACTOR ASSEMBLY (ELECTRO/MECHANICAL ONLY) b.) 200 to 240 volts ac for two wire 200 or 240 volt models. 5. Disconnect the brewer from the power source. If voltage is present as described, proceed to #6. If voltage is not present as described, refer to the Wiring Diagrams and check the brewer wiring harness. 6. Check for continuity between the two black wires of the contactor coil.
SERVICE (cont.) CONTACTOR ASSEMBLY (ELECTRO/MECHANICAL ONLY) (cont.) Removal and Replacement: 1. Remove all wires from the contactor. 2. Remove the two #10-32 screws securing contactor to the inside of the hood. 3. Securely install the new contactor inside the hood. 4. Refer to Fig. 7 when reconnecting the wires.
b.) 200 to 240 volts ac for two wire 200 or 240 volt models. Voltage must not be indicated across these terminals when the thermostat is turned "OFF" (fully counterclockwise). 6. Disconnect the brewer from the power source. LOCK SERVICE (cont.) CONTROL THERMOSTAT (ELECTRO/MECHANICAL ONLY) LOCK SET SET J2 If voltage is present as described, reinstall the capillary tube into the tank to the line 7" above the bulb, the control thermostat is operating properly.
SERVICE (cont.) DISPENSE VALVE 5. Check the dispense valve for coil action. Connect the brewer to power source. Place the "ON/OFF (Warmer)" switch in the "ON" (upper) position, press and release the start switch. Listen carefully in the vicinity of the dispense valve for a "clicking" sound as the coil magnet attracts and repels the plunger. 6. Disconnect the brewer from the power source.
SERVICE (cont.) DIGITAL BREWER CONTROL BOARD AND DISPLAY (DBC) P1094.35 FIG. 12 DIGITAL CONTROL BOARD Location The digital control board is located inside the upper front of the trunk on the component bracket. The digital display is located in the upper center of the front of hood. NOTE: Check the function list (supplied) for FUNCTION, ENTRY AND DESCRIPTION. 1. If display indicates a "FAULT" use the list below to troubleshoot the indicated fault.
SERVICE (cont.) DIGITAL BREWER CONTROL BOARD AND DISPLAY (DBC) (cont.) heater relay or triac. ("0" means the temperature will be allowed to vary by the value in "set relay temperature difference") 7. If you cannot access the DBC with the password you have entered, the password has been changed. If you know what the brew settings are you can "reset" the memory back to the way it left the factory, which is "0".
SERVICE (cont.) 6. Apply heat sink compound and secure new triac assembly on rear of the heat sink with one #6-32 screw. 7. Route the triac wires through the tank support channel. 8. Secure triac/heat sink assembly to the lower rear of the brewer with two #6-32 screws. 9. Reconnect the wires of the new triac assembly. Refer to Fig. 14 when reconnecting wires. TRIAC/HEAT SINK ASSEMBLY (DBC ONLY) WHI/VIO to Terminal Block (Red Insert) BLU to Tank Heater BLU to DBC Board J1-17 TAN to DBC Board J1-16 FIG.
SERVICE (cont.) LOCK LEVEL CONTROL BOARD AND LEVEL PROBE (Electro/ mechanical only) LOCK SET SET J2 TL1 TL2 TL4 TL3 TL5 J1 FLOWure gpm press 0 .500 ting 0.050 opera # 2230 00) rol 26.05 NN max Cont #205 psig 00) er 90 low BU 21.00 Wash ner/F #237 Strai en l. Flow Scre l. (Rep (Rep TER T WA HO ! UTI CA ON 6. Carefully connect a piece of insulated jumper wire to terminal 4. Keep the other end of this wire away from any metal surface of the brewer. 7.
SERVICE (cont.) LEVEL CONTROL BOARD AND LEVEL PROBE (Electro/ mechanical only)(cont.) b.) 200 to 240 volts ac for two wire 200 or 240 volt models after a delay of approximately 1 second. 17. Disconnect the brewer from the power source. If voltage is present as described, reinstall the probe, the level control board and level probe are operating properly. If voltage is not present as described, check the pink probe wire for continuity. If no continuity is present, replace or repair pink wire.
SERVICE (cont.) LIMIT THERMOSTAT LOCK Removal and Replacement 1. Remove all wires from the limit thermostat terminals. 2. Carefully remove the two #8-32 nuts securing the limit thermostat to tank lid and remove limit thermostat. 3. Carefully secure new limit thermostat to tank lid. 4. Refer to Fig. 18 when reconnecting the wires. LOCK SET SET J2 TL1 TL2 TL4 TL3 TL5 J1 BLK to Terminal Block (Black Insert) BLK to Tank Heater FLOW sure gpm pres 00 .500 0.05 ating 2230 500) # oper rol 26.
SERVICE (cont.) ON/OFF (Warmer) SWITCH If voltage is not present as described, refer to the Wiring Diagrams and check the brewer wiring harness. 5. With the black wire removed, remove the white/ violet wire or white/red wire on the switch from the lower left terminal. 6. Check for continuity across the center and lower left terminal with switch in the "ON" (upper) position. Continuity must not be present when switch is in the "OFF" (lower) position.
Removal and Replacement: 1. Disconnect the red leads from the overflow protection switch from the black wire from the terminal block or DBC board assembly and the blue wire from the thermostat or red wire from DBC board assembly. 2. Remove the nut beneath the copper overflow cup. 3. Remove the entire switch assembly from the cup. 4. Place the new switch assembly into the cup, wires first. Make sure that a gasket is in place around the threaded switch stem.
SERVICE (cont.) c.) Red and violet wires on 200 and 240V volt electro/mechanical controlled models. d.) Red and white/blue wires on 200 and 240 volt DBC models. Connect the brewer to the power source. The indication must be: a.) 120 volts ac for three wire 120/208 volt models and three wire 120/240 volt models. b.) 200 to 240 volts ac for two wire 200 or 240 volt models. 4. Disconnect the brewer from the power source.
SERVICE (cont.) SOLENOID VALVE (Refill) (cont.) 9. Slide flow control bracket and solenoid as an assembly over flow control and secure with four #8-32 screws to the support bracket. 10. Securely fasten the water lines to and from the solenoid valve and flow control. 11. Refer to Fig. 24 when reconnecting the wires.
SERVICE (cont.) START SWITCH Removal and Replacement: 1. Remove all wires from the switch terminals. 2. Compress the clips inside the hood and gently push the switch through the opening. 3. Push the new switch into the opening and spread the clips to hold the switch in the hood. 4. Refer to FIG. 26 when reconnecting the wires. WHI/ORN to Timer TL3 (Electro/Mechanical) or BLK to DBC J3-6 WHI/YEL to Timer TL5 (Electro/Mechanical) or BLU to DBC J3-21 FIG. 26 START SWITCH TERMINALS FIG.
SERVICE (cont.) TANK HEATER If voltage is present as described, proceed to #4. If voltage is not present as described, refer to the Wiring Diagrams and check the wiring harness. 4. Disconnect wires from the tank heater. 5. Check for continuity across the terminals of the tank heater. LOCK If continuity is present as described, reconnect the wires, the tank heater is operating properly. If continuity is not present as described, replace the tank heater.
SERVICE (cont.) TIMER (ELECTRO/MECHANICAL ONLY)(EARLY MODELS) OLD STYLE P1093 FIG. 29 TIMER Location: The timer is located inside the right front of the brewer on the upper part of the component bracket. Test Procedures: 1. Disconnect the brewer from the power source. 2. Disconnect the wires from the timer terminals TL3, TL4 and TL5 and rotate the dial(s) fully counterclockwise. 3.
SERVICE (cont.) DIGITAL TIMER (ELECTRO/MECHANICAL ONLY) (LATE MODELS) nals TL1 and TL4 when the "ON/OFF" switch is in the "ON" (upper) position. Connect the brewer to the power source. The indication must be 0 volts. LOCK If voltage is as described, proceed to #7. If voltage is not as described, disconnect the brewer from the power source and replace the timer. LOCK SET SET J2 TL1 TL2 TL4 TL3 TL5 J1 NEW STYLE FLOW sure gpm pres 00 .500 0.05 ating 500) # 2230 oper rol 26.
SERVICE (cont.) DIGITAL TIMER (ELECTRO/MECHANICAL ONLY) (LATE MODELS)(cont.) Timer Setting: NOTE: Prior to setting or modifying volumes, check that the brewer is connected to water supply, the tank is properly filled, and a funnel and server are in place. NOTE: All volume settings must be done with the sprayhead installed. NOTE: The timer must be adjusted for each individual batch setting. View the level of the liquid being dispensed. When the desired level is reached, turn the ON/OFF switch to "OFF".
SERVICE (cont.) WARMER ELEMENT 4. Disconnect wires from the warmer element. 5. Check the continuity across the two terminals on the warmer element. If continuity is present as described, reconnect the white or red wire and white/red wires, or the white or red wire and white/violet wires on the warmer element. If continuity is not present as described, replace the warmer element. FIG. 33 WARMER ELEMENT P1111.35 Location: The warmer element is located on the bottom the base (warmer) plate.
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