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Bunn U3 Operating & Service Manual

Manual is about: Bunn U3: Reference Guide

Summary of U3

  • Page 1

    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, ...

  • Page 2

    Page 2 10060 100908 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) comp...

  • Page 3: Warning

    Page 3 warning very hot water use with care! 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...

  • Page 4

    Page 4 electrical requirements caution - the brewer must be disconnected from the power source until specified in initial set-up. U333 & u3833 requires 3-wire, grounded service rated 240 volt ac, 35 amp or 440 volts ac, 30 amp for u333,three phase, 60 hz or 380 volts ac, 30 amp for u3833, three phas...

  • Page 5

    Page 5 initial setup 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...

  • Page 6

    Page 6 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...

  • Page 7

    Page 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 cof...

  • Page 8

    Page 8 problem brew cycle will not start probable cause 1. No water 2. No power or incorrect voltage to the brewer remedy water lines and valves to the brewer must be open. (a1) check the terminal block for 120 volts ac across the red and white terminals and the black and white terminal on three wir...

  • Page 9

    Page 9 troubleshooting (cont.) problem brew cycle will not start (cont) brew cycle starts with brew lockout relay engaged. Probable cause 2. No power or incorrect voltage to the brewer (cont) 3. Water level below pump housing. (water level in the hot water gauge glass should be approximately half fu...

  • Page 10

    Page 10 troubleshooting (cont.) problem tank not filling water running out of the over- flow probable cause 1.On/off switch (this switch must be in the "on" position for the refill circuit to operate. 2. No water 3. Solenoid valve 4. Probe 5. Liquid level board 1.Brewer not level 2. Solenoid valve 3...

  • Page 11

    Page 11 probable cause 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 1. Circuit breaker 2. Tank heater(s) 1. Timer 2. Start switch 1. Timer 2. Solenoid valve 3. Lime b...

  • Page 12

    Page 12 troubleshooting (cont.) problem funnels overflow (cont.) coffee reservoir overflows brewer is making unusal noises probable cause remedy 3. Pump - flow rate 4. Soft water 1. Coffee reservoir not completely empty befor a brew cycle was started. 2. Timer 3. Pump - flow rate 1. Solenoid valve 2...

  • Page 13

    Page 13 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 electri- cal equipmen...

  • Page 14

    Page 14 service (cont.) circuit breaker (120/208v and 120/240v three wire models and 440v four wire models) location: the circuit breaker is located on the right rear of the component bracket. Test procedures: 1. Disconnect the brewer from the power source. 2. Disconnect the black wire from the main...

  • Page 15

    Page 15 p2209.60 fig. 4 contactor contactor location: the contactor is located on the left front of the component bracket test procedures: 1. Disconnect the brewer from the power source. 2a. 120/208v, 120/240v, 380v three wire models, 380v and 440v four wire models disconnect the black wire from the...

  • Page 16

    Page 16 red to left tank heater (t2) red to terminal block(l2) blk thermal fuse to left tank heater blk to left tank heater (l1) blk to right tank heater (t1) blk to terminal block (l1) red to right tank heater (l2) whi from main harness (120/208v,120/240v,380v three wire models, 380v and 440v four ...

  • Page 17

    Page 17 service (cont.) control thermostat fig. 6 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. Locate the thermostat and the voltage check points. 3. Connect th...

  • Page 18

    Page 18 service (cont.) fuse and fuse holder (208v, 240v, 230v two wire models and 380v three wire models) 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 f...

  • Page 19

    Page 19 limit thermostat service (cont.) p1800 fig. 11 limit thermostat terminals fig. 10 limit thermostat p2209.60 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 sourc...

  • Page 20

    Page 20 8. Disconnect the brewer from the power source and remove the jumper wire from terminal 4. If voltage is present as described, liquid level board is operating properly, proceed to #9. If voltage is not present as described, replace the liquid level board. Liquid level board and level probe f...

  • Page 21

    Page 21 service (cont.) liquid level board and level probe (cont.) t1 blu to solenoid valve t2 blk to on/off switch (all models except 230v-ce models) t3 whi to main harness (120/208v, 120/240v, four wire 380v and 440v models) t3 whi to transformer (380v three wire models) t3 red to main harness (20...

  • Page 22

    Page 22 5. Disconnect the wires on the on/off switch. 6. A) 120/208v, 120/240v, 208v, 240v, 380v and 440v models - check for continuity across the terminals on the rear of the switch with the switch in the "on" (upper) position. Continuity must not be present when the switch is in the "off" (lower) ...

  • Page 23

    Page 23 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 bla...

  • Page 24

    Page 24 relay (brewers w/brew lockout) fig.18 relay p1731.55 location: the relay is located on the front part of the com- ponent bracket, mounted on the top of the timer bracket. Test procedures: all models except 230v - ce models 1. Disconnect the brewer from the power source. 2. Disconnect the wir...

  • Page 25

    Page 25 service (cont.) relay (brewers w/brew lockout) b 9 6 8 5 7 b 6 9 8 5 a 1 4 7 2 3 a 1 4 2 3 120/208v, 120/240v, 208v, 380v, 440v and 240v models prior to #u300004095 230v models #u300004095 and up fig.19 relay terminals p1739 red from main harness blu from brew timer blk to control thermostat...

  • Page 26

    Page 26 selector switch (half batch option) fig. 20 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. Check for...

  • Page 27

    Page 27 service (cont.) solenoid fig. 22 solenoid p2209.60 location: the solenoid is mounted on the upper left rear of the component bracket. Test procedures: 1. Disconnect the dispenser from the power source. 2. A) for 120/208 volt and 120/240 volt three wire, single phase models, 380 volt three wi...

  • Page 28

    Page 28 service (cont.) solenoid 6. Remove the tank inlet tube grommet and dis- card. 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.....

  • Page 29

    Page 29 start switch (brew) fig. 24 start switch (brew) p1317.30 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 termi- nals. 3. Check for co...

  • Page 30

    Page 30 blk to contactor t1 (all models except 230v-ce models) blk (thermal fuse) to contactor top left termi- nal) (230v-ce models) red to contactor t2 (all models except 230v-ce models) red (thermal fuse) to con- tactor top right terminal) (230v-ce models) blk to contactor l1 (120/208v, 120/240 th...

  • Page 31

    Page 31 service (cont.) thermal fuses (230v-ce models only) j2 tl 1 tl 2 tl 3 tl 4 tl5 j1 fig. 28 thermal fuses p1750.65 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 th...

  • Page 32

    Page 32 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 ...

  • Page 33

    Page 33 digital timer (late models) fig. 32 digital timer p2209.60 service (cont.) 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 bo...

  • Page 34

    Page 34 service (cont.) digital timer (late models) blu/blk wire from tl5 to p1 whi/grn wire from tl4 to (whi) pump whi/blu wire from tl3 to (blk) pump whi wire from tl2 to p2 blk wire from tl1 to p3 j2 - three pin connector from half/full batch switch p2037 fig. 33 digital timer terminals note: all...

  • Page 35

    Page 35 blk from terminal block service (cont.) transformer (380v three wire models only) fig. 34 transformer p1752.55 location: the transformer is located on the top rear of the timer mounting bracket. Test procedures: 1. Disconnect the brewer from the power source. 2. Disconnect black wire and the...

  • Page 36

    Page 36 master on/off switch (late models) service (cont.) fig. 37 master on/off switch wiring location: the master on/off switch is located in the top hous- ing at the rear, fig. 36. Test procedure: 1. Disconnect the brewer from the power source and remove the wires from all terminals of the master...

  • Page 37

    Page 37 n l1 l2 whi blk red main on/off switch (late models only) red blk 10492.0000e 03/07 © 1990 bunn-o-matic corporation 120/208 volts ac 120/240 volts ac 3 wire + gnd single phase 10060 011708.

  • Page 38

    Page 38 10060 080900

  • Page 39

    Page 39 schematic wiring diagram u3a & u38a (brewers prior to u300004095) 10060 080900

  • Page 40

    Page 40 schematic wiring diagram u3a - ce (brewers s/n u300004095 - up) 10060 080900

  • Page 41

    Page 41 schematic wiring diagram u3833 10060 080900

  • Page 42

    Page 42 schematic wiring digram u3833 10060 080900