Bunn U3A Operating & Service Manual
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Bunn U3A Operating & Service Manual

Bunn u3a: service manual
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BUNN
®
U3A
OPERATING & SERVICE MANUAL
BUNN-O-MATIC CORPORATION
POST OFFICE BOX 3227
SPRINGFIELD, ILLINOIS 62708-3227
PHONE: (217) 529-6601 FAX: (217) 529-6644
www.bunnomatic.com
10060.0003A 07/02 ©2002 Bunn-O-Matic Corporation

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  • Page 1 BUNN ® OPERATING & SERVICE MANUAL BUNN-O-MATIC CORPORATION POST OFFICE BOX 3227 SPRINGFIELD, ILLINOIS 62708-3227 PHONE: (217) 529-6601 FAX: (217) 529-6644 www.bunnomatic.com 10060.0003A 07/02 ©2002 Bunn-O-Matic Corporation...
  • Page 2 SOLE OPTION AS SPECIFIED HEREIN, TO REPAIR, 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 substitute equipment, facilities or services, or any other special, incidental or consequential damages.
  • Page 3 USER NOTICES Carefully read and follow all notices on the brewer and in this manual. They were written for your protection. All notices on the brewer are to be kept in good condition. Replace any unreadable or damaged labels. #00656.0000 #00831.0000 ATTENTION: TURN OFF WHEN UNATTENDED #00878.0000...
  • Page 4 3/8" flare. NOTE - Bunn-O-Matic recommends 3/8" copper tubing for installations from the 1/2" water supply line. Bunn-O- Matic does not recommend the use of a saddle valve to install the brewer. The size and shape of the hole made in the supply line by this type of device may restrict water flow.
  • Page 5 CAUTION - The brewer must be disconnected from the power source throughout the Initial Setup , except when specified in the instructions. IMPORTANT: Brewer must be level and installed on a sturdy structure. Electrician's and Plumber's Instructions are provided. These instructions should be carefully followed before proceeding with Initial Setup .
  • Page 6 CAUTION - Disconnect the power source from the brewer prior to the removal of any panel for the replacement or adjustment of any component. NOTE: Prior to setting or modifying batch sizes, check that the brewer is connected to water supply, the tank is properly filled, and a funnel support, funnel and funnel cover are in place.
  • Page 7 1. Brew 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 a Bunn ®...
  • Page 8 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.
  • Page 9 TROUBLESHOOTING (cont.) PROBLEM Brew cycle will not start (cont.) Tank not filling PROBABLE CAUSE 6. Start Switch 7. Timer 8. Pump 9. Solenoid Valve 10. Strainer 1.ON/OFF Switch (This switch must be in the "ON" position for the refill circuit to operate.) 2.
  • Page 10 4. Probe 5. Manual fill and drain valve un- derneath brewer open. 1. Limit Thermostat CAUTION - Do not eliminate or bypass limit thermostat. Use only Bunn-O-Matic replacement part #29329.1000. 2. Control Thermostat 3. Tank Heater(s) 4. Contactor 5. Thermal Fuse.
  • Page 11 Refer to Service - Solenoid Valve for testing procedures. See page Remove swing spout and insert deliming rod down into pump tub- ing as far as possible. Use Bunn ® filters made for the U3 brewer. Remove obstruction. Check pump flow rate with a watch.
  • Page 12 TROUBLESHOOTING (cont.) PROBLEM Coffee reservoir overflows Brewer is making unusal noises PROBABLE CAUSE 1. Coffee reservoir not completely empty before a brew cycle was started. 2. Timer 3. Pump - Flow Rate 1. Plumbing lines 2. Water supply 3. Tank Heater(s) Page 12 REMEDY Be sure coffee reservoir is empty...

  • Page 13: Table Of Contents

    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 elec- trical equipment should be performed only by quali- fied service personnel.

  • Page 14: Contactor

    SERVICE (cont.) CONTACTOR (cont.) Test Procedures: 1. Disconnect the brewer from the power source. 2. Disconnect the red wire from the limit thermostat to the contactor coil and the black wire from the main harness to the contactor coil. 3. Connect the brewer to the power source. 4.

  • Page 15: Control Thermostat

    SERVICE (cont.) CONTROL THERMOSTAT FIG. 4 CONTROL THERMOSTAT 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. Locate the thermostat and check for 230 volts between the red wire from the main harness on the control thermostat and the black wire on the main terminal block...

  • Page 16: Fuse And Fuse Holder

    SERVICE (cont.) FUSE AND FUSE HOLDER FIG.6 FUSE AND FUSE HOLDER Location: The fuse and fuse holder are located on the right rear of the component bracket. Test Procedures: 1. Disconnect the brewer from the power source. 2. Remove the cap and fuse from the fuse holder. 3.

  • Page 17: Limit Thermostat

    SERVICE (cont.) LIMIT THERMOSTAT FIG. 8 LIMIT THERMOSTAT Location: The limit thermostat is located on the center front of the component bracket behind the timer mounting bracket. Test Procedures: 1. Disconnect the brewer from the power source. 2. Disconnect the red wires from the limit thermo- stat.
  • Page 18 SERVICE (cont.) LIQUID LEVEL BOARD AND LEVEL PROBE (cont.) touching the frame. Repeat these several times. Keep in mind there is an approximate five second delay for output to stabilize. 8. Disconnect the brewer from the power source and remove the jumper wire from T4. If voltage is present as described, liquid level board is operating properly, proceed to #9.

  • Page 19: On/Off Switch

    SERVICE (cont.) ON/OFF SWITCH FIG.12 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.

  • Page 20: Pump

    SERVICE (cont.) PUMP ASSEMBLY FIG.14 PUMP ASSEMBLY 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 red wire from the black lead on the pump.

  • Page 21: Selector Switch (Half Batch)

    SERVICE (cont.) SELECTOR SWITCH (HALF BATCH OPTION) FIG. 16 SELECTOR SWITCH (HALF BATCH) Location: The selector switch is located in the upper center of the switch mounting panel. Test Procedures: 1. Disconnect the brewer from the power source. 2. Disconnect the wires from the switch terminals. 3.

  • Page 22: Solenoid

    SERVICE (cont.) SOLENOID FIG. 18 SOLENOID Location: The solenoid is mounted on the upper left rear of the component bracket. Test Procedures: 1. Drain 1/2 gallon of water from the faucet in order to activate the probe. 2. Disconnect the brewer from the power source. 3.

  • Page 23: Start Switch (Brew)

    SERVICE (cont.) START SWITCH (BREW) FIG. 20 START SWITCH (BREW) Location: The brew start switch is located on the upper right side of the brewer component housing. Test Procedures: 1. Disconnect the brewer from the power source. 2. Remove the wires from the start switch terminals. 3.

  • Page 24: Swing Arm Switch

    SERVICE (cont.) SWING ARM SWITCH FIG. 22 SWING ARM SWITCH Location: The swing arm switch is attached to the cupola cover. Test Procedures: 1. Disconnect the brewer from the power source. 2. Remove the cupola cover end caps, swing spout and cupola cover.

  • Page 25: Tank Heaters

    SERVICE (cont.) TANK HEATERS FIG. 24 TANK HEATER Location: The tank heaters are located on the right center and the left center of the component bracket. BLK (Thermal Fuse) to Contactor Lower Left Ter- minal LEFT Test Procedures: 1. Disconnect the brewer from the power source. 2.

  • Page 26: Thermal Fuses

    SERVICE (cont.) THERMAL FUSES FIG. 26 THERMAL FUSES Location: The thermal fuses are mounted between the tank heater terminals and contactor terminals or terminal block. Test Procedures: 1. Disconnect the brewer from the power source. 2. Disconnect the thermal fuses from the tank heater terminal and the contactor terminal or terminal block.
  • Page 27 SERVICE (cont.) TIMER (Early Models)OLD STYLE(cont.) If voltage is present as described, proceed to #8. If voltage is not present as described, refer to the wiring diagram and check the brewer wiring harness. 8. Disconnect the black and white wires to the swing arm switch and pump leads.

  • Page 28: Digital Timer (Late Models)

    SERVICE (cont.) DIGITAL TIMER (Late Models) NEW STYLE FIG. 29 DIGITAL TIMER Location: The timer is located on the front center of the component bracket. Test Procedure. NOTE: Do not remove or install wires while timer board is installed. Pressure applied to one side may cause damage to the board.
  • Page 29 SERVICE (cont.) DIGITAL TIMER (Late Models) 1. Modifying brew volumes. To modify a brew vol- ume, 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.
  • Page 30 10493.0004A 07/02 © 2002 BUNN-O-MATIC CORPORATION 10060.3 070102 Page 30...

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