Manuals / Bunn / Kitchen Appliance / Coffeemaker

Bunn U3 TROUBLESHOOTING cont PROBLEM, Funnels overflow cont Coffee reservoir overflows, Remedy

Models: U3A U3

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TROUBLESHOOTING (cont.)

PROBLEM

Funnels overflow (cont.)

Coffee reservoir overflows

Brewer is making unusal noises

PROBABLE CAUSE

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.Plumbing lines

3.Water supply

4.Tank Heater(s)

REMEDY

Check pump flow rate with a watch. Pump flow rate should be approxi- mately 24 ounces in 15 seconds. Be sure pump assembly is free of any obstructions.

When using a water softener, a coarse grind of coffee may be preferred. If required, a bypass system is available as an optional feature.

Be sure coffee reservoir is empty before brew cycle is started.

Refer to Service -Timer for testing procedures. See page 31 or 33

Check pump flow rate with a watch. Pump flow rate should be approxi- mately 24 ounces in 15 seconds. Be sure pump assembly is free of any obstructions.

The nut on the solenoid must be tight or it will vibrate during operation.

Plumbing lines should not be rest- ing on the counter top.

(A)The brewer must be connected to a cold water line.

(B)Water pressure to the brewer must not exceed 90 psi (620 kPa). Install a regulator if necessary to lower the pressure to approxi- mately 50 psi (345 kPa).

Remove and clean lime off the tank heater. See page 30

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Bunn U3A TROUBLESHOOTING cont PROBLEM, Funnels overflow cont Coffee reservoir overflows, Probable Cause, Remedy

Contents

OPERATING & SERVICE MANUAL U3 U3ABUNN-O-MATIC CORPORATION BUNN-O-MATIC COMMERCIAL PRODUCT WARRANTY PageINTRODUCTION USER NOTICESATTENTION TURN OFF WHEN UNATTENDED Very Hot Water Use With CareELECTRICAL INSTALLATION INSTRUCTIONS ELECTRICAL REQUIREMENTSINITIAL SETUP CE REQUIREMENTSPLUMBING REQUIREMENTS INITIAL SETUP cont ADJUSTING BREW VOLUMESVolumes CLEANING COFFEE BREWINGFILTER HOLDER TROUBLESHOOTING PROBLEMPROBABLE CAUSE TROUBLESHOOTING cont PROBLEM PROBABLE CAUSEREMEDY TROUBLESHOOTING cont PROBLEMPROBABLE CAUSE TROUBLESHOOTING cont PROBLEM Refer to Service - Contactor for testing procedures. See pagePROBABLE CAUSE REMEDYTROUBLESHOOTING cont PROBLEM Funnels overflow cont Coffee reservoir overflowsPROBABLE CAUSE REMEDYSERVICE COMPONENT ACCESSContents SERVICE cont Wire Models and 440V Four Wire ModelsCONTACTOR SERVICE cont2A. 120/208V, 120/240V, 380V THREE WIRE MODELS SERVICE cont CONTACTOR cont BLK to Right TankTank Heater BLK Thermal Fuse to Right Tank Heater BLK to Terminal Block L1SERVICE cont CONTROL THERMOSTAT Disconnect the wires from the control thermoInstall thermostat and mounting bracket on the FIG. 6 CONTROL THERMOSTATSERVICE cont FIG.8 FUSE AND FUSE HILDERFIG. 9 FUSE HOLDER TERMINALS SERVICE cont LIMIT THERMOSTAT Disconnect the brewer from the power sourceWith an ohmmeter, check for continuity across SERVICE cont LIQUID LEVEL BOARD AND LEVEL PROBE VoltageSERVICE cont LIQUID LEVEL BOARD AND LEVEL PROBE contSERVICE cont ON/OFF SWITCH RED to Start Switch, Brew Timer & Liquid Level BoardFIG. 15 ON/OFF SWITCH TERMINALS SERVICE cont PUMP ASSEMBLY SERVICE cont RELAY BREWERS W/BREW LOCKOUT SERVICE cont RELAY BREWERS W/BREW LOCKOUT BLU fromSERVICE cont SELECTOR SWITCH HALF BATCH OPTION SOLENOID SERVICE cont2. A For 120/208 volt and 120/240 volt three wire, single phase models, 380 volt three wire, three phase models and 380 volt, 440 volt four wire, three phase models, disconnect the black wire from the liquid level board #2 and the white wire on the solenoid. With a voltmeter, check the voltage across the black and the white wire. Connect the brewer to the power source. The indication must be SERVICE cont SOLENOID SERVICE cont START SWITCH BREW FIG. 24 START SWITCH BREWSERVICE cont TANK HEATERS LEFTFIG. 27 TANK HEATER TERMINALS SERVICE cont THERMAL FUSES 230V-CE MODELS ONLY TIMER Early ModelsFIG. 28 THERMAL FUSES SERVICE cont TIMER Early Modelscont To Three Pin FemaleSERVICE cont DIGITAL TIMER Late Models SERVICE cont DIGITAL TIMER Late Models NOTE All volume settings must be done with the sprayhead installedNOTE Half-Batch and full batch settings must each be set separately FIG. 33 DIGITAL TIMER TERMINALSSERVICE cont TRANSFORMER 380V THREE WIRE MODELS ONLYFIG. 35 TRANSFORMER TERMINALS SERVICE cont MASTER ON/OFF SWITCH Late Models FIG. 36 MASTER ON/OFF SWITCH LOC120/208 VOLTS AC 120/240 VOLTS AC 3 WIRE + GND SINGLE PHASE MAIN ON/OFF SWITCH Late Models onlyPage 10060Page 10060080900 SCHEMATIC WIRING DIAGRAM U3A & U38A BREWERS PRIOR TO U300004095 Page10060 080900SCHEMATIC WIRING DIAGRAM U3A - CE BREWERS S/N U300004095 - UP Page10060 080900SCHEMATIC WIRING DIAGRAM U3833 Page10060 080900SCHEMATIC WIRING DIGRAM U3833 Page10060 080900