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BUNN
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OPERATING & SERVICE MANUAL
BUNN-O-MATIC CORPORA TION OF
CANADA LTD.
280 INDUSTRIAL PARKWAY SOUTH
AURORA, ONTARIO. L4G 3T9
PHONE: (905) 841-2866 FAX: (905) 841-2775
10218.7000 3/00 ©1994 Bunn-O-Matic Corporation
Page 2
CONTENTS
Introduction .............................................................................. 2
Warranty ................................................................................... 2
User Notices.............................................................................. 3
Electrical Requirements ............................................................ 4
Operating Controls ....................................................................4
Initial Set-Up ............................................................................. 4
Cleaning .................................................................................... 5
Coffee Grinding ......................................................................... 5
Adjustments ..............................................................................6
Troubleshooting ........................................................................ 7
Service .................................................................................... 10
Wiring Diagram .......................................................................20
INTRODUCTION
This equipment will store up-to six pounds of whole bean coffee in each of two hoppers and grind it to a preset grind and amount into
an awaiting funnel and filter from most commercial drip coffee brewers. The equipment is only for indoor use on a sturdy counter or shelf.
Adequate space must be available above the grinder to raise the lids when adding beans. Use only with whole bean coffee.
The grind is preset at the factory to fine specifications as set forth by the United States Department of Commerce and
adopted by the Coffee Brewing Center of the Pan American Coffee Bureau. Adjustments may be made to alter both the
amount and grind from the factory setting.
BUNN-O-MATIC COMMERCIAL GRINDER WARRANTY
Bunn-O-Matic Corp. (“Bunn”) warrants the equipment manufactured by it to be commercially free from defects in material and workmanship existing at the time of manufacture and appearing within one year from the date of installation. In
addition, Bunn warrants that the grinding burrs will grind coffee to meet original factory screen sieve analysis for three years
from date of installation or for 30,000 pounds of coffee, whichever comes first. This warranty does not apply to any equipment, component or part that was not manufactured by Bunn or that, in Bunn’s judgement, has been affected by misuse,
neglect, alteration, improper installation or operation, improper maintenance or repair, damage or casualty.
THE FOREGOING WARRANTY IS EXCLUSIVE AND IS IN LIEU OF ANY OTHER WARRANTY, WRITTEN OR ORAL, EXPRESS OR
IMPLIED, INCLUDING, BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF EITHER MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. The agents, dealers or employees of Bunn are not authorized to make modifications to this warranty or to make additional
warranties that are binding on Bunn. Accordingly, statements by such individuals, whether oral or written, do not constitute warranties and
should not be relied upon.
The Buyer shall give Bunn prompt notice of any claim to be made under this warranty by telephone at (905) 841-2866 or
by writing to 280 Industrial Parkway South, Aurora, Ontario L4G 3T9. If requested by Bunn, the Buyer shall ship the
defective equipment prepaid to an authorized Bunn service location. If Bunn determines, in its sole discretion, that the
equipment does not conform to the warranty, Bunn shall repair the equipment with no charge for parts during the one year
warranty period and no charge for labor by a Bunn Authorized Service Representative during the one year warranty period.
If Bunn determines that repair is not feasible, Bunn shall, at its sole option, replace the equipment or refund the purchase
price for the equipment.
THE BUYER’S REMEDY AGAINST BUNN FOR THE BREACH OF ANY OBLIGATION ARISING OUT OF THE SALE
OF THIS EQUIPMENT, WHETHER DERIVED FROM WARRANTY OR OTHERWISE, SHALL BE LIMITED, AS SPECIFIED HEREIN, TO REPAIR OR, AT BUNN’S SOLE OPTION, REPLACEMENT OR REFUND. Bunn shall not 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, inciden-
tal or consequential damages.
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Page 3
USER NOTICES
Carefully read and follow all notices on the grinder and in this manual. They were written for your protection. All notices on the
grinder are to be kept in good condition. Replace any unreadable or damaged labels.
WARNING
Use only on a properly protected circuit
capable of the rated load.
Electrically ground the chassis.
Follow national/local electrical codes.
Do not use near combustibles.
An extension cord, when used, must be shorter
than 20 feet if 16-gage 3-conductor wire, or
shorter than 10 feet if 18-gage 3-conductor wire.
CAUTION
PERSONAL INJURY
HAZARD.
KEEP FINGERS AND
FOREIGN OBJECTS
OUT OF HOPPER
OR CHUTE OPENING.
#05876.7999
DISPENSE TIME (Seconds)
DISPLAY
Increase Decrease
+
FAILURE TO COMPLY RISKS EQUIPMENT
DAMAGE, FIRE, OR SHOCK HAZARD
READ THE ENTIRE OPERATING MANUAL
INCLUDING THE LIMIT OF WARRANTY AND
LIABILITY BEFORE BUYING OR USING THIS PRODUCT
20545-0000 7/90 © 1990 Bunn-O-Matic Corporation
#20545.7000
DISPENSE TIME
3.2
(SECONDS)
20
15
10
6
H
I
H
G
L
O
W
HIGH
3
25
11
30
32
4
22
20
15
10
6
3.2
.4.4
H
I
H
G
L
O
W
HIGH
3
25
30
32
4
Readout will be displayed for 5 minutes.
Timer can only be adjusted
while readout is displayed.
WARNING
HAZARDOUS VOLTAGE
UNPLUG GRINDER
BEFORE REMOVING!
#05942.0000
LEFT
LOW
RIGHT
LOW
WARNING
HAZARDOUS VOLTAGE
UNPLUG GRINDER
BEFORE REMOVING
#25763.0000
3
Page 4
ELECTRICAL REQUIREMENTS
This grinder has an attached cordset and requires 2-wire, grounded service rated 120 volts ac,
15 amp, single phase, 60 Hz.
OPERATING CONTROLS
Off/On/Start Switch
OFF - (upper position) Switching to this position stops all operation of the grinder.
ON - (middle position) The switch will return to this position after a grind cycle has begun and
will remain in this position after grinding has ceased.
START - (lower, momentary position) Pressing the switch initiates
a timed grind cycle.
Hopper Selector Switch
Left - Switching to this position allows beans to be dispensed
from the left hopper.
Right - Switching to this position allows beans to be dispensed
from the right hopper.
P633
Dispense Timer
The dispense timer controls the amount of beans that will leave the hopper in a grind cycle. The
timer can be adjusted to dispense a different amount from each hopper. The scale is from 0.4 to
150.0 seconds. Refer to the Adjustments section for timer setting chart (page 7).
INITIAL SET-UP
1. Open the top lid. Clear all foreign objects and shipping material from
the hopper compartment and the entrance to the grind chamber.
2. Remove the lower front inspection panel.
3. Plug-in the grinder.
4. Select either the right or left hopper with the selector switch. Do
not press the start switch.
5. If grinder has an analog timer, proceed to step 6. If grinder has a
digital timer, momentarily press the center (DISPLAY) button on
the dispense timer panel. The readout will indicate the present
timer setting in seconds and will remain displayed for five minutes.
6. Adjust the timer setting to obtain the desired amount of coffee for the selected hopper.
7. Repeat steps 4 thru 6 for the other hopper.
8. Fill the hopper compartments with whole bean coffee. (Capacity 6 pounds each). The grinder is
now ready for use.
P633
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Page 5
CLEANING
The use of a damp cloth rinsed in any mild, non-abrasive, liquid detergent is recommended for cleaning all
surfaces on Bunn-O-Matic equipment. Care should be taken not to scratch the hopper or windows with any
abrasive material. Regular cleaning will keep your grinder looking new for years.
COFFEE GRINDING
P598P597 P599 P600 P601
STEP 1 STEP 2 STEP 3 STEP 4 STEPS 5 & 6
1. Visually inspect the desired hopper for an ample supply of whole bean coffee.
2. Place a paper filter into the brew funnel. The filter must not be folded-over or tilted to one side.
3. Insert the funnel into the funnel rails and push until it stops.
4. Momentarily press the start switch. The grinding action will stop automatically after the preset amount of
ground coffee is dispensed into the funnel.
5. Remove the funnel from the grinder and level the bed of grounds by gently shaking.
6. The loaded funnel is now ready for use in any commercial drip coffee brewer according to the manufacturer’s
instructions.
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Page 6
ADJUSTMENTS
The grind can be set from very fine to very coarse. The amount may be adjusted for use in most commercial coffee brewers. The following procedures should be used to make adjustments. A change in the burr adjustment will also change the amount dispensed. Any adjustment of the burrs should be followed by an adjustment
of the timer.
Burr Adjustment
1. Unplug the grinder and empty all beans from the hoppers.
2. Plug-in the grinder, momentarily press the off/on/start switch to the
“START” (lower) position (with either hopper selected) and release, run a
few grind cycles until all of the coffee in the grind chamber is used-up.
O
C
3. Remove the upper front inspection panel.
4. Loosen the burr adjustment screw from its locked position.
5. Hand loosen the adjustment locking nut around the screw approximately
one turn.
6. Press the off/on/start switch to the “START” (lower) position and release,
slowly turn the adjusting screw in a clockwise direction until a metallic
whine is heard due to the rubbing of the grinding burrs. (It may be neces-
sary to start more than one grind cycle to obtain this sound.)
7. Make a mark with a pen on the decal to note the position of the arrow on the grind adjustment screw.
8. The following settings approximately correspond to the CBC recognized grinds. All are referenced from the
arrow position noted in #7.
-
F
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P581
P581
FINE GRIND: Rotate the adjusting screw 7 hash marks in a counterclockwise direction.
DRIP GRIND: Rotate the adjusting screw 8 hash marks in a counterclockwise direction.
REGULAR (COARSE) GRIND: Rotate the adjusting screw 12 hash marks in a counterclockwise direction.
9. Hold the adjusting screw in its set position with a screwdriver while tightening the lock nut to a snug
position by hand. Slightly loosen the adjusting screw and retighten it to its prior position. The lock nut
should now be tight against the burr housing front cover.
Timer Adjustment
1. Unplug the grinder and remove the lower front inspection panel.
2. Determine the grind setting. (The factory setting is fine, to determine other settings, refer to the
previous section.)
3. Use the table on the next page to find approximate timer setting for the grind and amount of coffee desired.
DISPENSE TIME (Seconds)
I 0.0
DISPLAY
Increase Decrease
+
Readout will be displayed for 5 minutes.
Timer can only be adjusted
while readout is displayed.
WARNING
HAZARDOUS VOLTAGE
DISPENSE TIME
20
15
3
25
10
6
30
3.2
32
4
H
I
H
G
L
O
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HIGH
LEFT
LOW
WARNING
HAZARDOUS VOLTAGE
(SECONDS)
11
RIGHT
22
20
15
3
25
10
6
30
3.2
.4.4
32
4
H
I
H
G
L
O
W
HIGH
LOW
UNPLUG GRINDER
BEFORE REMOVING!
DIGITAL TIMER
UNPLUG GRINDER
BEFORE REMOVING
ANALOG TIMER
P595
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Page 7
ADJUSTMENTS (cont.)
4. Plug-in the grinder. Select either the right or left hopper with the selector switch. Do not press
the start switch.
5. If grinder has an analog timer, proceed to step 6. If grinder has a digital timer, momentarily press the center
(DISPLAY) button on the dispense timer panel. The readout will indicate the present timer setting in seconds and will remain displayed for five minutes.
6. Adjust the timer setting to obtain the desired amount of coffee for the selected hopper.
7. Verify the setting by weighing a few samples. Use the following table as an approximate guide only.
8. Repeat steps 4 thru 7 for the other hopper.
APPROXIMATE TIMER SETTINGS IN SECONDS
Weight Fine Drip Regular
(ounces) (7*) (8*) (12*)
1.5 0.5 0.5 0.5
1.75 0.7 0.6 0.6
2.0 1.0 0.8 0.8
2.25 1.4 1.4 1.2
2.5 1.9 1.8 1.6
2.75 2.4 2.2 2.0
3.0 2.9 2.7 2.5
3.25 3.3 3.1 2.9
4.0 4.8 4.4 4.0
6.0 8.6 7.9 7.5
8.0 12.0 11.5 10.9
10.0 15.7 15.1 14.1
12.0 19.6 18.5 17.5
14.0 23.5 22.0 20.9
16.0 27.0 25.3 24.3
*Hash mark settings. Refer to
Adjustment-Burr
section.
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. Shorting
of terminals or the application of external voltages may result in board failure.
• Intermittent operation of electronic circuit boards is unlikely. Board failure will normally be permanent. If an intermittent condition is encountered, the cause will likely be a switch contact or a
loose connection at a terminal or crimp.
• Make certain that all electrical connections are tight and isolated.
WARNING
• Exercise extreme caution when servicing electrical equipment.
• Turn power OFF when servicing, except when electrical tests are specified.
• Follow recommended service procedures.
• Replace all protective shields or safety notices.
7
Page 8
TROUBLESHOOTING (cont.)
Problem
Grinder will not start.
Probable Cause
1. No power or incorrect voltage
2. Off/On/Start switch
3. Timer
4. Relay
5. Motor overload protector
Remedy
(A) Plug-in the grinder.
(B) Check the voltage at the wall
outlet with a voltmeter. It must
be 120 volts ac.
(A) Momentarily press the Off/On/
Start switch to the “START” (lower)
position.
(B) Refer to
switch for testing procedures. See
page 11.
Refer to
testing procedures. See page 17.
Refer to
procedures. See page 14.
Remove the cover plate located on
the right side of the housing. Press
the red “Reset” button. Listen
carefully for a “click”. This resets the
motor protection circuit and indicates that an overload may have
been encountered by the motor. (An
overload can occur when something
other than coffee is inserted into the
hopper for grinding.) Refer to
Service
procedures. See page 12.
Service
Service
Service
Motor for disassembly
- Off/On/Start
- Timer for
- Relay for testing
Grinder will not shut off.
6. Motor
1. Off/On/Start switch
2. Timer
8
Refer to
procedures. See page 12.
(A) Place the switch in the “OFF/
STOP” position.
(B) Refer to
Switch for testing procedures. See
page 11.
Refer to
procedures. See page 17.
Service
Service
Service
- Motor for testing
- Off/On/Start
- Timer for testing
Page 9
Probable Cause
Remedy
3. Relay
1. Hoppers
2. Bottoms of hoppers
Refer to
Service
- Relay for testing
procedures. See page 14.
Begin each grind cycle by visually
inspecting the hoppers for ample
supplies of whole bean coffee.
Foreign materials must not block the
openings at the bottom of the hoppers.
Refer to
Service
- Off/On/Start switch
for testing procedures. See page 11j0 -1.92 TD0.00A) Che bloo ss. thngs at slid. Slgn s themove freelyloo visowhole sloo travelmple
9
Page 10
SERVICE
This section provides procedures for testing and
replacing various major components used in this
grinder should service become necessary. Refer to
Troubleshooting
cause of any problem.
WARNING - Inspection, testing, and repair of electri-
cal equipment should be performed only by qualified
service personnel. The grinder should be unplugged
when servicing, except when electrical tests are required and the test procedure specifically states to
plug-in the grinder.
Component Access
WARNING - Unplug the grinder before the removal of
any panel or the replacement of any component.
All components are accessible by the removal
of the upper and lower front inspection panels, hopper assembly, and rear panel.
for assistance in determining the
WARNING
Use only on a properly protected circuit
capable of the rated load.
Electrically ground the chassis.
Follow national/local electrical codes.
Do not use near combustibles.
An extension cord, when used, must be shorter
than 20 feet if 16-gage 3-conductor wire, or
shorter than 10 feet if 18-gage 3-conductor wire.
FAILURE TO COMPLY RISKS EQUIPMENT
DAMAGE, FIRE, OR SHOCK HAZARD
READ THE ENTIRE OPERATING MANUAL
INCLUDING THE LIMIT OF WARRANTY AND
LIABILITY BEFORE BUYING OR USING THIS PRODUCT
20545-0000 7/90 © 1990 Bunn-O-Matic Corporation
NOTICE
For connection to Bunn-Omatic
Coffee Brewer Models:
Dual, OT, Single, & System III only.
(24 volt N.E.C. Class 2 circuit only.)
BUNN
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The rear panel is attached with eight 8-32 slot-
ted head screws.
P604
The upper front inspection panel is attached with
two 6-32 slotted head screws.
CAUTION
PERSONAL INJURY
HAZARD.
KEEP FINGERS AND
FOREIGN OBJECTS
OUT OF HOPPER
OR CHUTE OPENING.
The lower front inspection panel is attached with
two 6-32 slotted head screws.
P602
P603
P605
The hopper assembly is attached with four 632 slotted head screws with locking nuts located on
the sides of the housing near the center and rear.
Removal of the hopper will also require disconnection of the solenoid wires from the grinder wiring harness.
Contents
Off/On/Start Switch............................................. 11
Motor.................................................................. 12
Relay .................................................................. 14
Slide Plate(s) ...................................................... 15
Snubber .............................................................. 16
Solenoid(s) ......................................................... 16
Timer .................................................................. 17
10
Page 11
SERVICE (cont.)
Off/On/Start Switch
If continuity is present as described, proceed
to #6.
If continuity is not present as described, re
place the switch.
6. Check for continuity across the right terminals
when the switch is placed in the “START” (lower)
position only.
If continuity is present as described, the
Off/On/Start switch is operating properly.
If continuity is not present as described,
replace the switch.
Location:
The Off/On/Start switch is located to the left side
on the front of the housing above the upper front
inspection panel.
Test Procedure:
1. Unplug the grinder.
2. Remove the black wire from the switch.
3. Check for continuity across the black wire from the
Off/On/Start switch and the left blade of the cordset
connector (see illustration below).
CORDSET CONNECTOR
Looking Straight-on
Black
Removal and Replacement:
1. Remove all wires from the switch terminals.
2. Compress the clips inside the front wrapper and
gently push the switch through the opening.
3. Push the new switch into the opening and spread
the clips to retain the switch in the hood.
4. Refer to the following illustration when reconnecting the wires.
If continuity is present as described, proceed
to #4.
If continuity is not present as described, refer
to the
Wiring Diagrams
and check the grinder
wiring harness.
4. Remove the remaining wires from the switch.
5. Check for continuity across the left terminals when
the switch is placed in both the “ON” (center) and
“START” (lower) positions.
11
Page 12
SERVICE (cont.)
Motor
P607
Location:
The motor is located in the upper wrapper.
Test Procedure:
1. Remove the cover plate located on the right side
of the housing. Press the red “Reset” button visible through the opening. Listen carefully for a
“click”. This resets the motor protection circuit
and may indicate that something other than coffee was inserted into the hopper for grinding.
If the grinder remains unable to start, proceed
to #2.
If the grinder stops operating shortly after start-
ing, refer to the removal and replacement steps to
gain access to the grind chamber. Remove any foreign materials that may be found.
2. Unplug the grinder.
3. Remove the electrical access panel at the rear
of the motor.
4. Check the voltage across terminals L1 & L2 of the
motor with a voltmeter when the Off/On/Start
switch is pressed to the “START” (lower) position
and released. Plug-in the grinder. The indication
must be 120 volts ac.
5. Unplug the grinder
If voltage is not present as described, refer to
the
Wiring Diagrams,
and check the grinder wiring
harness.
Removal and Replacement - MOTOR
1. Remove all wires from the solenoids and lift the
hopper assy out of the grinder housing.
2. Remove all wires from the Off/On/Start switch,
motor, and motor mounting plate.
3. The entire wiring harness must be fed into the
bottom of the grinder housing through the hole
in the motor mounting plate.
4. Remove both 6-32 screws beneath the upper
front inspection panel.
5. Remove the six 10-32, slotted, hex head screws
on top of the motor mounting plate.
6. Slowly slide the assembly out the rear of the
grinder housing. The mounting plate may have
to be raised to gain clearance for the motor hardware and wiring harness bushing.
7. Remove the four 5/16"-18 bolts and nuts to separate the motor from the mounting plate.
8. Mount the new motor and tighten the four bolts
and nuts. They should be tightened approximately one full turn past snug.
9. Slide the motor mounting plate into the rear of
the grinder housing.
10. Feed the wiring harness into the top of the housing through the hole in the motor plate.
11. Reinstall the six 10-32 hex head screws through
the motor plate and the two 6-32 slotted head
screws through the housing.
12. Reattach the green wire to the 10-32 stud on
the motor mounting plate.
13. Refer to the
Off/On/Start switch
section when
reconnecting the switch wires.
14. Refer to the
Solenoid
section when reconnect-
ing the solenoid wires.
15. Refer to the following illustration when reconnecting the wires.
If voltage is present as described and the grinder
remains unable to start, replace the motor.
12
Page 13
SERVICE (cont.)
Motor (cont.)
WHI/ BLU to Snubber
WHI/BLU to Relay
WHI/BLK to Cordset
WHI/BLK to Snubber
GRN to Chasis Ground
YEL to Snubber
Removal and Replacement - GRIND CHAMBER
1. Remove the two 1/4"-20 screws holding the front
cover to the burr housing. Carefully remove the
burr housing front cover. Inspect the adjusting
screw to see if the thrust plug is worn.
Replace if excessively worn or damaged.
2. Carefully remove the rotor cup, shear plate, and
burr rotor from the grinder. Inspect the shear
plate and burrs for wear.
Replace if excessively worn or damaged.
3 Remove and inspect the stationary burr for wear.
Replace if excessively worn or damaged.
4. Inspect the grind chamber and remove any foreign materials. The burrs will not properly seat
in the chamber if any material or coffee particles
remain.
5. Reinstall the stationary burr, burr rotor, shear
plate, rotor cup, and dial plate to the burr housing.
6. Refer to the
Adjustments
section to vary the
grind dispensed.
P621
13
Page 14
SERVICE (cont.)
Relay
Grinders with Digital Timer
N
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I
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Timer can only be adjusted
Readout will be displayed for 5 minutes.
while readout is displayed.
W
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2
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B
the
Wiring Diagrams
and check the grinder wiring
harness.
4. Remove the white/red and white/blue wires from
the relay contacts.
5. Check for continuity across the relay contacts
when the Off/On/Start switch is pressed to the
“START” (lower) position and released. Plug-in
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the grinder. Continuity must be present for the
approximate setting on the timer.
6. Unplug the grinder.
If continuity is present as described, reconnect
the white/red and white/blue wires, the relay is operating properly.
If continuity is not present as described, replace
the relay.
Removal and Replacement
1. Remove all wires from the relay terminals.
3
E
0
2
2
IM
5
2
T
5
E
1
)
S
S
N
D
E
N
P
0
O
3
C
E
0
S
1
(
2
3
4
1
6
2
.
3
H
G
I
H
4
.
W
O
L
H
G
I
H
F
F
O
N
O
T
H
G
I
R
W
O
L
E
G
G
A
IN
T
L
N
O
R
V
S
U
O
R
E
D
G
N
I
N
I
R
V
G
O
G
M
U
E
L
R
E
R
2. Remove the 6-32 screw fastening the relay to
the timer bracket.
3. Mount the new relay to the timer bracket and
tighten the screw.
4. Refer to the following illustration when recon-
necting the wires.
Grinders with Analog Timer
P609
Location:
The relay is located on the timer bracket in the
grinder base. The bracket can be removed by loosening the two 8-32 slotted head screws beneath the timer
dial.
Test Procedure:
1. Unplug the grinder.
2. Check the voltage across the red/black and
white/green wires of the relay coil with a volt-
meter when the Off/On/Start switch is pressed
to the “START” (lower) position and released.
Plug-in the grinder. The indication must be 120
volts ac for the approximate setting on the timer.
3. Unplug the grinder.
If voltage is present as described, reconnect the
red/black and white/green wires to the relay coil, and
proceed to #4.
If voltage is not present as described, refer to
WHI/BLU to
Motor L1
RED/BLK to
Timer P4-7
WHI/RED to
Timer P4-6
WHI/GRN to
Timer P4-3
P610
14
Page 15
SERVICE (cont.)
Slide Plate(s)
Location:
The slide plates are located on the solenoid
mounting plate immediately beneath the hopper openings.
The slide plates must always remain flat for
proper operation.
Test Procedure:
With the solenoid mounting plate attached to
the hopper, push the solenoid plunger into the coil.
The slide plate must move freely in the assembly and
snap closed when the plunger is released. Repeat for
the other slide plate.
If the slide plates move as described, they are
operating correctly.
If the slide plates do not move as described, the
problem may be in any one or more of the linkage
pieces, springs, slide plates, and/or the solenoid
mounting plate. Disassemble the solenoid mounting
plate assembly and inspect all components for free
movement.
Replace if excessively worn or damaged.
Removal and Replacement:
1. Remove the hopper from the grinder.
2. Remove six slotted head screws holding the
solenoid mounting panel to the hopper.
3. The slide plate with attached linkage can be lifted
off the pivot pin and removed with the solenoid
plunger.
4. Refer to the illustration above when reassembling the components.
5. Inspect the slide plates after reassembly.
They must move freely.
15
Page 16
SERVICE (cont.)
Snubber
Solenoid(s)
Location:
The snubber is located at the back of the motor
attached to the right side of the wiring harness.
Removal and Replacement:
1. Remove the snubber wires from the motor terminals.
2. Cut the ties holding the snubber to the wiring
harness.
3. Refer to the following illustration when reconnecting the wires.
4. Fasten the snubber to the wiring harness using
new ties.
Location:
The solenoids are located on the mounting plate
immediately beneath the hoppers.
Test Procedure:
1. Unplug the grinder.
2. Check the voltage across the left or right solenoid coil terminals with a voltmeter when the
Off/On/Start switch is momentarily pressed to
the “START” (lower) position and released (hopper selector switch must be corresponding to
the suspect solenoid). Plug-in the grinder. The
indication must be 120 volts ac.
3. Unplug the grinder.
If voltage is present as described, proceed to #4.
If voltage is not present as described, refer to
the
Wiring Diagram
ness.
and check the grinder wiring har-
4. Separate the connectors on the white/brown
wires of the solenoids from the connectors on
the grinder wiring harness. (White/orange and
red/black to the left solenoid and white/yellow
and red/black to the right solenoid.)
5. Check for continuity across the white/brown
wires on the suspect solenoid coil.
16
Page 17
SERVICE (cont.)
Solenoid(s) (cont.)
If continuity is present as described, reconnect
the white/brown wires to the grinder wiring harness,
and proceed to #6.
If continuity is not present as described, replace
the solenoid.
6. Check the solenoid for coil action when the con-
trol switch is momentarily pressed to the
“START” (lower) position and released. Plug-in
the grinder. Listen carefully in the vicinity of the
solenoid for a “clicking” sound as the coil magnet attracts and after a period of time, repels the
plunger.
7. Unplug the grinder.
RED/BLK to
Right Solenoid
RED/BLK to
Timer P4-7
WHI/ORN to
Timer P4-4
Timer
Left
WHI/YEL to
Timer P4-5
RED/BLK to
Left Solenoid
Right
P612
If the sound is heard as described and the
plunger remains unable to move or move freely, refer
to the slide plate section.
If the sound is not heard as described, replace
the solenoid
Removal and Replacement:
1. Remove the hopper assy from the grinder.
2. Remove the four 8-32 slotted-head screws hold-
ing the solenoid coil to the solenoid panel.
3. Feed the white/brown wires through the hole in
the solenoid mounting plate and loosely install
the new solenoid coil.
4. Look through the collector on the bottom of the
assy and adjust the slide plate travel distance
when installing the solenoid coil.
5. Push the solenoid plunger into the solenoid coil
with your hand while moving the coil forward
or backward in its mounting holes.
6. Securely tighten the mounting screws when the
slide plate appears to have no metal showing in
the front or back of the hopper hole.
7. Refer to the following illustration when recon-
necting the wires.
DISPENSE TIME (Seconds)
Decrease
DISPLAY
.
s
e
t
u
n
i
m
5
r
Increase
d
o
f
e
t
d
s
e
u
j
.
y
d
d
a
l
a
e
p
y
s
e
i
a
l
b
d
p
y
s
l
e
i
n
b
d
+
l
o
l
s
i
i
n
w
t
a
t
u
c
u
o
r
o
d
e
E
d
a
m
a
e
i
G
r
e
T
A
R
le
i
T
h
L
w
O
V
S
U
WARNING
O
D
R
A
Z
A
H
UNPLUG GRINDER
BEFORE REMOVING
Digital Timer
3
E
0
2
2
IM
5
2
T
5
E
1
S
N
E
NDS)
P
0
3
IS
0
D
1
(SECO
2
3
4
1
6
3
2
.
3
H
0
2
G
2
I
H
5
4
2
.
W
5
O
1
L
H
G
I
0
H
3
0
1
2
3
F
F
O
4
1
6
2
.
N
3
H
O
G
T
I
H
H
G
4
I
.
R
W
O
L
W
O
L
H
G
I
H
T
F
E
L
F
F
O
E
N
G
O
A
T
L
O
W
V
O
L
S
U
WARNING
O
D
R
A
Z
A
H
UNPLUG GRINDER
BEFORE REMOVING
Analog Timer
P613
Location:
The timer is located in the grinder base.
Test Procedure:
1. Unplug the grinder.
2. Check the voltage across contacts 1 & 2 of the
larger connector on the timer board with a voltmeter whenever the grinder is plugged-in. Plugin the grinder. The indication must be 120 volts
ac.
3. Unplug the grinder.
17
Page 18
SERVICE (cont.)
Timer (cont.)
4. Check the voltage across contacts 2 & 6 of the
larger connector on the timer board with a voltmeter when the control switch is in any position
except “OFF” (center). Plug-in the grinder. The indication must be 120 volts ac.
5. Unplug the grinder.
If voltage is present as described, proceed to
#6.
If voltage is not present as described, refer to
the
Wiring Diagram
ness.
6. Check the voltage across contacts 3 & 7 of the
larger connector on the timer board with a voltmeter after the Off/On/Start switch has been momentarily pressed to “START” (lower) position and
released. Plug-in the grinder. The indication must
be 120 volts ac.
7. Unplug the grinder.
and check the grinder wiring har-
has been momentarily pressed to the right
“START” (lower) position and released. Plug-in
the grinder. The indication must be 120 volts ac
and should remain for the approximate timer
setting.
11. Unplug the grinder.
If voltage is present as described, the timer is
operating properly.
If voltage is not present as described, replace
the timer.
Removal and Replacement:
1. Separate the grinder wiring harness connectors
from the timer circuit board.
2. Remove the relay from the timer bracket.
3. Attach the relay to the new timer bracket.
4. Refer to the following illustration when reattaching the connectors.
5. Refer to the
ume dispensed.
Adjustments
section to reset the vol-
If voltage is present as described, proceed to
#8.
If voltage is not present as described, replace
the timer.
8. Check the voltage across contacts 4 & 7 of the
larger connector on the timer board with a voltmeter after the hopper selector switch is set to
the left position and the Off/On/Start switch has
been momentarily pressed to the “START”
(lower) position and released. Plug-in the
grinder. The indication must be 120 volts ac and
should remain for the approximate timer setting.
9. Unplug the grinder.
If voltage is present as described, proceed to
#10.
If voltage is not present as described, replace
the timer.
10. Check the voltage across contacts 5 & 7 of the
larger connector on the timer board with a voltmeter after the hopper selector switch is set to
the right position and the Off/On/Start switch
18
Page 19
SERVICE (cont.)
Timer (cont.)
(P1-8) BLU to Off/On/Start Switch,
Selector Switch
(P1-6) ORA to Selector Switch
BLK to Cordset
BLK to Off/On/Start Switch
WHI/BLK to Cordset
WHI/GRN to Relay Coil
WHI/ORN to Left Solenoid
WHI/YEL to Right Solenoid
WHI/RED to Off/On/Start Switch
WHI/RED to Relay Contact
RED/BLK to Relay Coil
RED/BLK to Left Solenoid
BLK to Off/On/Start Switch
WHI/BLK to Cordset
WHI/GRN to Relay Coil
WHI/ORN to Left Solenoid
1
P4
8
Digital Timer
1
P4
(P1-2) VIO to Off/On/Start Switch
(P1-1) YEL to Selector Switch
P1
8
1
P2
1
3
1
P3
11
(P1-8) BLU to Off/On/Start Switch,
8
P1
1
(P1-6) ORA to Selector Switch
Selector Switch
(P1-2) VIO to Off/On/Start Switch
(P1-1) YEL to Selector Switch
WHI/YEL to Right Solenoid
WHI/RED to Off/On/Start Switch
WHI/RED to Relay Contact
RED/BLK to Relay Coil
RED/BLK to Left Solenoid
8
Analog Timer
P614
19
Page 20
L1 N
BLK
YEL
VIO
GRY
TAN
ORA
BLU
WHI/RED
WHI/BLK
WHI/GRN
WHI/ORA
WHI/YEL
RED/BLK
RT
SOL
1
WHI/BLU
SOL
YEL
LT
2
SNUBBER
WHI/BLK
K1
120 VOLTS AC
2 WIRE
SINGLE PHASE
60 HZ
WHI/RED WHI/BLK
10756.0000G 3/97 © 1993 BUNN-O-MATIC CORPORATION
K1 N.O.
WHI/BLU
M
L2L1
20
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