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Page 17

LIMIT THERMOSTAT

SERVICE (cont.)

FIG. 9 LIMIT THERMOSTAT TERMINALS

FIG. 8 LIMIT THERMOSTAT

P2178.55

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.

3. Check for continuity across the limit thermostat

terminals with an ohmmeter.

If continuity is present as described, the limit thermo-
stat is operating properly.
If continuity is not present as described, replace the
limit thermostat.

Removal and Replacement:
1. Remove the wires from the limit thermostat termi-

nals.

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. 9 and reconnect the wires.

RED to Control
Thermostat

RED to Contactor
Coil

LIQUID LEVEL BOARD AND LEVEL PROBE

FIG.10 LIQUID LEVEL BOARD AND

LEVEL PROBE

P2178.55

Location:

The liquid level board is located on the left rear of

the component bracket. The level probe is located on
the right rear of the component bracket.

Test Procedures:
1. Disconnect the brewer from the power source.
2. Disconnect the blue wire (T1) and the pink wire

(T4).

3. Check for 230 volts ac across terminals (T2) and

(T3) with the ON/OFF switch in the "ON" position.

4. Disconnect the brewer from the power source.

If voltage is present as described, proceed to #5.
If voltage is not present as described, refer to wiring
diagram and check the brewer wiring harness.

5. Reconnect the blue wire to T1 on the liquid level

board.

6. Carefully connect a piece of insulated jumper wire

to T4. Keep the other end of this wire away from
any metal surface of the brewer.

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 simu-
lates "NEED WATER" condition. Connect the brewer
to the power source, simulate each condition while
measuring the voltage between T1 and T3 on the
liquid level board. The voltage should be 0 volts
with jumper touching frame and 230 volts ac not

10060.3  070102

Summary of Contents for U3A

Page 1: ...NG 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 U3A BUNN 10060 0003A 07 02 2002 Bunn O Matic Corp...

Page 2: ...ted by BUNN shipping the defective equipment prepaid to an authorized BUNN service location and 3 receiving prior authorization from BUNN that the defective equipment is under warranty THE FOREGOING W...

Page 3: ...ewer 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 00878 0000 12593 0000 03408 0000 03409...

Page 4: ...cold water system with operating pressure between 20 and 90 psi 138 and 620 kPa from a 1 2 or larger supply line A shut off valve should be installed in the line before the brewer Install a regulator...

Page 5: ...nect the brewer to the power source and wait for the water in the tank to heat to the proper temperature This will take approximately 1 2 hours depending on the incoming water temperature Some water w...

Page 6: ...the water stream from the swing arm Release the switch Failure to release the switch within two seconds after the third break in the water stream causes the volume setting to be aborted and previous v...

Page 7: ...damp cloth 2 Drain both coffee reservoirs by opening coffee faucets When empty close faucets 3 Cycle two or three inches of water into each coffee reservoir adding a bucket of crushed ice to obtain a...

Page 8: ...airofelectricalequipmentshouldbeperformedonlybyqualifiedservicepersonnel All electronic components have 230 volt ac and low voltage dc potential on their terminals Shorting of terminals or the applica...

Page 9: ...ng procedures See page 20 Refer to Service Solenoid Valve for testing procedures See page 22 A Direction of flow arrow must be pointing towards brewer B Remove the strainer and check for obstructions...

Page 10: ...r must be level and installed on a sturdy structure Refer to Service Solenoid Valve for testing procedures See page 22 Refer to Service Liquid Level Board for testing procedures See page 17 Refer to S...

Page 11: ...rtoService Timerfortesting procedures See page 26 or 28 Refer to Service Start Switch for testing procedures See page 23 RefertoService Timerfortesting procedures See page 26 or 28 Refer to Service So...

Page 12: ...to Service Timer for test ing procedures See page 26 or 28 Checkpumpflowratewithawatch Pumpflowrateshouldbeapproxi mately 24 ounces in 15 seconds Be sure pump assembly is free of any obstructions Plum...

Page 13: ...tthebrewerfromthepower source before the removal of any panel or the replace ment of any component All components are accessible by the removal of the swing spout front cupola cover rear cupola cover...

Page 14: ...ce If voltage is present as described proceed to 9 If voltage is not present as described refer to the wiring diagrams and check the brewer wiring harness 9 Check for continuity across the terminals o...

Page 15: ...hermostat Removal and Replacement 1 Disconnect the wires from the control thermostat 2 Remove the thermostat capillary bulb by firmly pullinguponthecapillaryatthecomponentbracket This will disengage t...

Page 16: ...178 60 RED from ON OFF Switch P2112 RED from Main Harness FUSE AND FUSE HOLDER Removal and Replacement Fuse 1 Remove the cap from the fuse holder 2 Remove fuse from the fuse holder inspect if blown di...

Page 17: ...EVEL BOARD AND LEVEL PROBE P2178 55 Location The liquid level board is located on the left rear of the component bracket The level probe is located on the right rear of the component bracket Test Proc...

Page 18: ...by touching the end of the probe to any metal surace of the brewer Measure the voltage be tween T1 and T3 on the liquid level board The voltage should be 0 volts with the probe touching the frame and...

Page 19: ...agram and check the brewer wiring harness 5 Disconnect all wires on the ON OFF switch 6 Check for continuity across the center terminal 2 andthelowerterminal 1 whentheswitchisinthe ON upper position C...

Page 20: ...pump does not run replace the pump If voltage is not present as described refer to the wiring diagram and check the brewer wiring harness Removal and Replacement Refer to Fig 15 1 Disconnect the wire...

Page 21: ...must not present when the switch is in the OPEN right full position If continuity is present as described the switch is operating properly If continuity is not present as described replace the switch...

Page 22: ...ribed reconnect the wires to the solenoid If continuity is not present as described replace the solenoid valve 7 Check the solenoid valve for coil action Connect thedispensertothepowersource Listencar...

Page 23: ...when the switch is in the upper position If continuity is present as described reconnect the wires the switch is operating properly If continuity is not present as described replace the switch BLU to...

Page 24: ...operating properly If continuity is not present as described replace the switch Removal and Replacement NOTE Measurethedistancefromthetopoftheswitch plunger to the hood cover The same distance is nee...

Page 25: ...he brewer from the power source 2 Disconnect the wires from each tank heater 3 Check for continuity across the terminals of each tank heater If continuity is present as described tank heaters are oper...

Page 26: ...he component bracket Test Procedures 1 Disconnect the brewer from the power source 2 Disconnectthepolarized threepinconnectorfrom the brewer main harness and rotate the brew timer dial fully countercl...

Page 27: ...uired If voltage is not present as described replace the timer Removal and Replacement 1 Separate all connectors between the brewer wir ing harness and the timer 2 Disconnect the timer leads from the...

Page 28: ...scribed disconnect the brewer from the power source and replace the timer 7 With a voltmeter check the voltage across termi nals TL1 and TL4 when the ON OFF switch is in the ON position Connectthebrew...

Page 29: ...stream from the swing arm Release the switch Failure to release the switch within two seconds after the third break in the water stream causes the volume setting to be aborted and previous volume sett...

Page 30: ...Page 30 10493 0004A 07 02 2002 BUNN O MATIC CORPORATION 10060 3 070102...

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