U3 U3A OPERATING & SERVICE MANUAL BUNN-O-MATIC CORPORATION POST OFFICE BOX 3227 SPRINGFIELD, ILLINOIS 62708-3227 PHONE: (217) 529-6601 FAX: (217) 529-6644 To ensure you have the latest revision of the Operating Manual, or to view the Illustrated Parts Catalog, Programming Manual, or Service Manual, please visit the Bunn-O-Matic website, at www.bunn.com. This is absolutely FREE, and the quickest way to obtain the latest catalog and manual updates.
BUNN-O-MATIC COMMERCIAL PRODUCT WARRANTY Bunn-O-Matic Corp. (“BUNN”) warrants equipment manufactured by it as follows: 1) All equipment other than as specified below: 2 years parts and 1 year labor. 2) Electronic circuit and/or control boards: parts and labor for 3 years. 3) Compressors on refrigeration equipment: 5 years parts and 1 year labor.
INTRODUCTION This brewer will brew a three gallon batch of coffee into each reservoir (one at a time). Each reservoir has its own dispensing faucet(s).The brewer also has a hot water faucet(s) for allied beverage use. It is only for indoor use on a sturdy counter where ambient temperature is in the range of 10-30°C (50-85°F). Brewer to be installed at a location where it can be overseen by trained personnel. USER NOTICES Carefully read and follow all notices on the brewer and in this manual.
ELECTRICAL REQUIREMENTS CAUTION - The brewer must be disconnected from the power source until specified in Initial Set-Up. RED L2 RED WHITE NEUTRAL L1 BLACK L2 120V A.C. BLUE 208 OR 240V A.C. L3 208V OR 240V 380V OR 440V BLACK 120V A.C. 208V OR 240V 380V OR 440V 208V OR 240V 380V OR 440V L1 GREEN GREEN P1841 P1843 U3 & U38 requires 3-wire, grounded service rated 120/208 or 120/240 volts ac, U3-30 amp,U38-40 amp, single phase, 60 Hz.
CE REQUIREMENTS • This appliance must be installed in locations where it can be overseen by trained personnel. • For proper operation, this appliance must be installed where the temperature is between 5°C to 35°C. • Appliance shall not be tilted more than 10° for safe operation. • An electrician must provide electrical service as specified in conformance with all local and national codes. • This appliance must not be cleaned by water jet.
INITIAL SETUP (cont.) 6. Brewing cycles may be started whenever water temperature is correct. This condition is indicated by the dial thermometer on front of the brewer. Whenever the pointer is in the green, brewer is ready for brewing. The recommended brewing temperature is approximately 200° F (93°C). Water temperature may be increased by turning thermostat knob clockwise, decreased by turning knob counterclockwise. 7.
COFFEE BREWING 1. Brewing cycles may be started whenever water temperature is correct. This condition is indicated by the dial thermometer on front of the brewer. Whenever the pointer is in the green, brewer is ready for brewing. 2. Insert Bunn® filter in funnel and add desired amount of coffee. 3. Level the bed of coffee and place funnel into the funnel support. Place funnel cover over the funnel and be sure the water swing spout is over the center of the funnel cover. 4.
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. • • • • • • • 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.
TROUBLESHOOTING (cont.) PROBLEM PROBABLE CAUSE REMEDY Brew cycle will not start (cont) 2. No power or incorrect voltage to the brewer (cont) (A4) Check the terminal block for 440 volts ac across the black and blue terminals, black and red terminals and the red and blue terminals on four wire three phase 440 volt models. (B) Check circuit breakers or fuses. 3. Water level below pump housing. (Water level in the hot water gauge glass should be approximately half full).
TROUBLESHOOTING (cont.) PROBLEM PROBABLE CAUSE REMEDY Tank not filling 1.ON/OFF Switch (This switch must be in the "ON" position for the refill circuit to operate. Refer to Service - ON/OFF Switch for testing procedures. See page 22 2. No water Be sure water shut-off is open and that in-line filters or strainers are not blocking water flow. (Do not confuse water shut-off valve with the manual fill and drain valve underneath brewer). 3.
TROUBLESHOOTING (cont.) PROBLEM PROBABLE CAUSE REMEDY Water not hot 1. Limit Thermostat CAUTION - Do not eliminate or bypass limit thermostat. Use only Bunn-O-Matic replacement part #29329.1000 Refer to Service - Limit Thermostat for testing procedures. See page19 2. Control Thermostat Refer to Service - Control Thermostat for testing procedures. See page 17 3. Tank Heater(s) Refer to Service - Tank Heater for testing procedures. See page 30 4.
TROUBLESHOOTING (cont.) PROBLEM PROBABLE CAUSE REMEDY Funnels overflow (cont.) 3. Pump - Flow Rate Check pump flow rate with a watch. Pump flow rate should be approximately 24 ounces in 15 seconds. Be sure pump assembly is free of any obstructions. 4. Soft Water Coffee reservoir overflows Brewer is making unusal noises When using a water softener, a coarse grind of coffee may be preferred. If required, a bypass system is available as an optional feature. 1.
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.) CIRCUIT BREAKER (120/208V and 120/240V Three Wire Models and 440V Four Wire Models) 4. With the black wire removed, remove the other black wire from the circuit breaker. 5. Check for continuity across the terminals on the circuit breaker. If continuity is present as described the circuit breaker is operating properly. If continuity is not present as described, press the reset button and repeat step 5, if continuity is not present as described, replace the circuit breaker.
SERVICE (cont.) CONTACTOR a) 120 volts ac for three wire 120/208, 120/240 volt and 380 volt models. b) 230 volts ac for two wire 230 volt models. c) 208 or 240 volts ac for two wire 208 or 240 volt models. d) 220 or 254 volts ac for four wire 280 or 440 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. FIG. 4 CONTACTOR P2209.
SERVICE (cont.) CONTACTOR (cont.) 9. Check for continuity across the terminals on the left side of the contactor by manually closing the contacts. Continuity must not present when the contact is released. 10. Check for continuity across the terminals on the right side of the contactor by manually closing the contacts.Continuity must not be present when the contact is released. If continuity is present as described, the contactor is operating properly.
SERVICE (cont.) CONTROL THERMOSTAT FIG. 6 CONTROL THERMOSTAT not be present when the thermostat is in the "OFF" position (fully counterclockwise). If continuity is present as described, the control thermostat is operating properly. If continuity is not present as described, replace the control thermostat. P2209.60 Location: The control thermostat is mounted on the right front of the component bracket. Test Procedures: 1. Disconnect the brewer from the power source. 2.
SERVICE (cont.) Removal and Replacement: Fuse: 1. Remove the cap from the fuse holder. 2. Remove fuse from the fuse holder, inspect, if blown discard. 3. Install new 5 amp fuse in the fuse holder. 4. Reinstall fuse holder cap. FUSE AND FUSE HOLDER (208V, 240V, 230V Two Wire Models and 380V Three Wire Models) Fuse Holder: 1. Disconnect the wires from the rear of the fuse holder. 2. Remove the nut securing the fuse holder to the component bracket. 3.
SERVICE (cont.) LIMIT THERMOSTAT FIG. 10 LIMIT THERMOSTAT Removal and Replacement: 1. Remove the wires from the limit thermostat terminals. 2. Carefully slide the limit thermostat out from under the retaining clip and remove the limit thermostat. 3. Carefully slide the new limit thermostat into the retaining clip. 4. Refer to Fig. 11 and reconnect the wires. P2209.60 Location: The limit thermostat is located on the center front of the component bracket behind the timer mounting bracket.
SERVICE (cont.) LIQUID LEVEL BOARD AND LEVEL PROBE 7. Touching the free end of the jumper to the brewer's frame simulates a "FULL" condition, preventing jumper from touching the brewer's frame simulates "NEED WATER" condition. Connect the brewer to the power source, simulate the conditions in the chart below while measuring the voltage between T1 and T3 0n the liquid level board. Repeat these several times. There is an approximate five second delay for output to stabilize. Model FIG.
SERVICE (cont.) LIQUID LEVEL BOARD AND LEVEL PROBE (cont.) 14. Disconnect the brewer from the power source. 9. Reconnect the pink wire to terminal 4. 10. Remove the two #8-32 screws securing the level probe to the component bracket. 11. Gently pull the probe out of the component bracket and inspect for corrosion. Replace if necessary. 12 Place the probe so that neither end is in contact with any metal surface of the brewer. 13. Connect the brewer to the power source.
SERVICE (cont.) ON/OFF SWITCH P2209.60 FIG.14 ON/OFF SWITCH Location: The ON/OFF switch is located on the left side of the switch mounting bracket. The switch mounting bracket is mounted on the front of the component bracket. Test Procedures: 1. Disconnect the brewer from the power source. 2. a)120/208V, 120/240V, 208V and 240V Models Remove the black wire on the ON/OFF switch from the fuse holder or circuit breaker and the red wire on the power indicator light.
SERVICE (cont.) PUMP ASSEMBLY FIG.16 PUMP ASSEMBLY P2209.60 Location: The pump is located on the center rear of the component bracket. Test Procedures: 1. Disconnect the brewer from the power source. 2. Disconnect the black wire from the black lead on the pump and the white wire from the black lead on the pump. 3. With a voltmeter, check the voltage across the black wire and the white wire. Connect the brewer to the power source.
SERVICE (cont.) RELAY (BREWERS W/BREW LOCKOUT) If continuity is present as described, reconnect the wires, the relay is operating properly. If continuity is not present as described, replace the relay. 230V - CE Models 1. Disconnect the brewer from the power source. 2. Disconnect the black wire from relay terminal "A" and the red wire from relay terminal "B". Check the voltage across the black and red wire with a voltmeter. Connect the brewer to the power source. The indication must be 230 volts ac.
SERVICE (cont.) RELAY (BREWERS W/BREW LOCKOUT) Removal and Replacement: 1. Disconnect the wires from the relay. 2. For 120/208V, 120/240V, 208V, 380V, 440V and 240V models prior to #U300004095 remove the #6-32 screw securing the relay to the relay mounting bracket. For 230V models #U300004095 and up, remove the two screws securing the relay to the relay mounting bracket. 3. Remove relay and discard. 4.
SERVICE (cont.) SELECTOR SWITCH (HALF BATCH OPTION) Removal and Replacement: 1. Remove the wires from the switch terminals. 2. Compress the clips on the back side of the switch mounting bracket and gently push the through the opening. 3. Push the new switch into the opening and spread the clips to hold switch in the mounting bracket. 4. Refer to Fig. 21 and reconnect the wires. P1317.30 FIG.
SERVICE (cont.) SOLENOID C) For 230V - CE two wire single phase models, disconnect the red wire from the liquid level board #2 and the black wire from the solenoid. With a voltmeter, check the voltage across the red wire and the black wire. Connect the brewer to the power source. The indication must be 230 volts ac. 3. Disconnect the dispenser from the power source. If voltage is present as described, proceed to #4.
SERVICE (cont.) SOLENOID 6. Remove the tank inlet tube grommet and discard. 7. Install new tank inlet tube grommet. 8. Install new solenoid assembly. 9. Install liquid level board, shield and secure solenoid assembly and shield to the component bracket with a #10-32 screw and flat washer.. 10. Install water inlet tube to connector on the solenoid. 11. Turn on the water supply to the brewer. 12. Refer to Fig. 23 and reconnect the wires.
SERVICE (cont.) START SWITCH (BREW) FIG. 24 START SWITCH (BREW) Removal and Replacement: 1. Remove the wires from the switch terminals. 2. Compress the clips on the back side of the switch mounting bracket and gently push the through the opening. 3. Push the new switch into the opening and spread the clips to hold switch in the mounting bracket. 4. Refer to Fig. 25 and reconnect the wires. BLU to Brew Timer or Brew Lockout Relay P1317.
SERVICE (cont.) Test Procedures: 1. Disconnect the brewer from the power source. 2. Disconnect the wires from the tank heater. 3. Check for continuity across the tank heater terminals. TANK HEATERS If continuity is present as described, proceed to #4. If continuity is not present as described, replace the tank heater. FIG. 26 TANK HEATER Removal and Replacement: 1. Remove the wires or thermal fuses from the tank heater. 2. Remove the four #8-32 screws securing the tank heater to the component bracket.
SERVICE (cont.) TIMER (Early Models) THERMAL FUSES (230V-CE MODELS ONLY) J2 TL1 TL4 TL3 TL5 TL2 J1 OLD STYLE FIG. 29 TIMER FIG. 28 THERMAL FUSES P1750.65 P1722.55 Location: Location: The thermal fuses are mounted on the tank heater terminals and the contactor terminals. Test Procedures: 1. Disconnect the brewer from the power source. 2. Disconnect the thermal fuse from the tank heater terminal and the contactor terminal. 3.
SERVICE (cont.) TIMER (Early Models)(cont.) 5. With a voltmeter, check the voltage across the sockets P1 and P2 (blue and white wires) of the female connector on the main harness when the "ON/OFF" switch is in the "ON" (upper) position and the start switch pressed. Connect the brewer to the power source. The indication must be: a) 120 volts ac for three wire 120/208 volt, 120/240 volt, 380 volt models and 208 or 240 volt ac for four wire 440 volt models.
SERVICE (cont.) 6. With a voltmeter, check the voltage across terminals TL1 and TL4 when the "ON/OFF" switch is in the "ON" position. Connect the brewer to the power source. The indication must be 0 volts. DIGITAL TIMER (Late Models) 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. FIG. 32 DIGITAL TIMER P2209.60 Location: The timer is located on the front center of the component bracket. Test Procedure.
SERVICE (cont.) DIGITAL TIMER (Late Models) NOTE: All volume settings must be done with the sprayhead installed. 1. Modifying brew volumes. To modify a brew volume, first check that the SET/LOCK switch is in the “SET” position on the circuit board. To increase a brew volume, place the ON/OFF switch in the “ON” position, press and hold the START switch until you see three breaks in the water stream from the swing arm. Release the switch and press it again one or more times.
SERVICE (cont.) TRANSFORMER (380V THREE WIRE MODELS ONLY) If voltage is present as described, the transformer is operating properly If voiltage is not present as described, replace the transformer. Removal and Replacement: 1. Disconnect all the wires from the transformer. 2. Remove the two #8-32 screws securing the transform to the transformer mounting bracket. 3. Remove the transformer and discard. 4. Position new transformer on transformer mounting bracket and secure with two #8-32 screws. 5.
SERVICE (cont.) MASTER ON/OFF SWITCH (Late Models) Removal and Replacement: 1. Remove all wires from the switch terminals. 2. Remove the two screws from the outside of the base and gently push the switch through the opening. 3. Locate the new switch into the opening and secure with screws removed in step 2. 4. Refer to FIG. 37 when reconnecting the wires. Incoming Power Supply L1 - BLK P1752.55 L2 - RED FIG. 36 MASTER ON/OFF SWITCH LOC.
N WHI L2 RED BLK L1 MAIN ON/OFF SWITCH (Late Models only) BLK RED 120/208 VOLTS AC 120/240 VOLTS AC 3 WIRE + GND SINGLE PHASE 10492.
Page 38 10060 080900
SCHEMATIC WIRING DIAGRAM U3A & U38A (BREWERS PRIOR TO U300004095) Page 39 10060 080900
SCHEMATIC WIRING DIAGRAM U3A - CE (BREWERS S/N U300004095 - UP) Page 40 10060 080900
SCHEMATIC WIRING DIAGRAM U3833 Page 41 10060 080900
SCHEMATIC WIRING DIGRAM U3833 Page 42 10060 080900
