Bunn SLF Instruction and safety manual

SL &
SL &
SLF
SLF
10304.0000E 11/99 © 1988 BUNN-O-MATIC CORPORATION
BUNN-O-MATIC CORPORATION
POST OFFICE BOX 3227
SPRINGFIELD, ILLINOIS 62708-3227
PHONE: [phone] FAX: [phone]
BUNN
®
OPERATING & SERVICE MANUAL
10043.0000D3/97© 1988BUNN-O-MATICCORPORATION
WHI
BLU
LIMIT
THERMOSTAT
SW.&
THERMOSTAT
TANKHEATER
N
BLK
L1
BLK
WHI
P1
P3
P2
P1,P2, & P3AREPINSOF
APOLARIZEDTHREE-PIN
CONNECTOR.
GREEN
SCHEMATIC WIRING DIAGRAM S
"KEEPWARM"HEATER
50W
WHI
TOPREAR
WARMER
100W
WHI
WHI
BLKBLU/BLK
TOPFRONT
WARMER
100W
WHI
BLKBRN/BLK
LOWERWARMER
100W
WHI
WHI
BLK
BLU/BLK
BRN/BLK
WHI
120VOLTSAC2WIRE
SINGLEPHASE
60HZ
1425W
WHI/VIO
!CAUTIONWARMERSANDSURFACESAREHOT
TOPFRONTON/LOWERSTART
TOPREARLOWERTOPFRONT
TOPREAR
10043.0000D3/97© 1988BUNN-O-MATICCORPORATION
WHI
BLU
LIMIT
THERMOSTAT
SW.&
THERMOSTAT
TANKHEATER
N
BLK
L1
BLK
WHI
P1
P3
P2
P1,P2, & P3AREPINSOF
APOLARIZEDTHREE-PIN
CONNECTOR.
GREEN
SCHEMATIC WIRING DIAGRAM S
"KEEPWARM"HEATER
50W
WHI
TOPREAR
WARMER
100W
WHI
WHI
BLKBLU/BLK
TOPFRONT
WARMER
100W
WHI
BLKBRN/BLK
LOWERWARMER
100W
WHI
WHI
BLK
BLU/BLK
BRN/BLK
WHI
120VOLTSAC2WIRE
SINGLEPHASE
60HZ
1425W
WHI/VIO
!CAUTIONWARMERSANDSURFACESAREHOT
TOPFRONTON/LOWERSTART
TOPREARLOWERTOPFRONT
TOPREAR
WARNING
HOT
WATER

Page 2
CONTENTS Introduction............................................................... 2
User Notices .............................................................. 3
Electrical Requirements............................................. 4
Plumbing Requirements ............................................ 5
Initial Set-Up.............................................................. 5
Operating Controls..................................................... 6
Cleaning..................................................................... 6
Coffee Brewing .......................................................... 6
Troubleshooting......................................................... 7
Service....................................................................... 12
Replacement parts..................................................... 25
Wiring Diagrams........................................................ 26
INTRODUCTION
This equipment will brew a half-gallon batch of coffee into an awaiting decanter at the press of a button. It
has two individually controlled warmers to keep the beverage in the decanters at the right temperature. The
model SLF will also dispense hot water on demand for other purposes. The brewer is only for indoor use on a
sturdy counter or shelf.
WARRANTY
Bunn-O-MaticCorp.(“Bunn”)warrantstheequipmentmanufacturedbyittobecommerciallyfreefromdefects
in material and workmanship existing at the time of manufacture and appearing within one year from the date of
installation. In addition:
1.)Bunnwarrantselectroniccircuitand/orcontrolboardstobecommerciallyfreefromdefectsinmaterialand
workmanship for two years from the date of installation.
2.)Bunnwarrantsthecompressoronrefrigerationequipmenttobecommerciallyfreefromdefectsinmaterial
and workmanship for two years from the date of installation.
3.)Bunnwarrantsthatthegrindingburrsoncoffeegrindingequipmentwillgrindcoffeetomeetoriginalfactory
screensieveanalysisforthreeyearsfromdateofinstallationorfor30,000poundsofcoffee,whichevercomesfirst.
Thiswarrantydoesnotapplytoanyequipment,componentorpartthatwasnotmanufacturedbyBunnorthat,
inBunn’sjudgement,hasbeenaffectedbymisuse,neglect,alteration,improperinstallationoroperation,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
MERCHANTABILITYORFITNESS FORAPARTICULAR PURPOSE.Theagents,dealers oremployeesofBunnare
not authorized to make modifications to this warranty or to make additional warranties that are binding on Bunn.
Accordingly,statementsbysuchindividuals,whetheroralorwritten,donotconstitutewarrantiesandshouldnot
be relied upon.
The Buyer shall give Bunn prompt notice of any claim to be made under this warranty by telephone at (217)
529-6601orbywritingtoPostOfficeBox3227,Springfield,Illinois,62708-3227.IfrequestedbyBunn,theBuyer
shall ship the defective equipment prepaid to an authorized Bunn service location. If Bunn determines, in its sole
discretion,that theequipment does notconform tothewarranty, Bunnshallrepair theequipment with nocharge
forparts during the warranty period and no charge for labor by a Bunn Authorized Service Representative during
the 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.
(Revised November 1999)

Page 3
THEBUYER’SREMEDYAGAINSTBUNNFORTHEBREACHOFANYOBLIGATIONARISINGOUTOFTHESALE
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.
InnoeventshallBunnbeliableforanyotherdamageorloss,including,butnotlimitedto,lostprofits,lostsales,
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.
USER NOTICES
Carefullyread and follow all notices on theequipment and in this manual. They werewritten for your protection.
All notices on the equipment should be kept in good condition. Replace any unreadable or damaged labels.
WARRANTY (cont.)
Fill water tank before turning -on
thermostat or connecting appliance
to power source.
Do not use near combustibles.
Follow national/local electrical codes.
Electrically ground the chassis.
Use only on a properly protected
circuit capable of the rated load.
FAILURE TO COMPLY RISKS EQUIPMENT
DAMAGE, FIRE, OR SHOCK HAZARD
READ THE ENTIRE OPERATING MANUAL
BEFORE BUYING OR USING THIS PRODUCT
THIS APPLIANCE IS HEATED WHENEVER
CONNECTED TO A POWER SOURCE
00831.0000F 3/98 © 1988 BUNN-O-MATIC CORPORATION
WARNING
!
00831.0000 00658.0000
02769.0000
(Revised November 1999)

Page 4
ELECTRICAL REQUIREMENTS
CAUTION - Do not connect the brewer to the power source until specified in Initial Set-Up.
MODEL 15 has an attached cordset, and requires 2-wire
grounded service rated 120 volts ac, 15 amp, single phase, 60
Hz.
MODEL 20 requires 2-wire, grounded service rated 120 volts
ac, 20 amp, single phase, 60 Hz. Proceed as follows:
MODEL35 requires 3-wire,
groundedservicerated120/208
or 120/240 volts ac, 20 amp,
single phase, 60 Hz. Proceed as
follows:
Electrical Hook-Up
CAUTION – Improper electrical installation will damage electronic components.
1. An electrician must provide electrical service as specified.
2. Using a voltmeter, check the voltage and color coding of each conductor at the electrical source.
3. Removethe frontpanel beneaththesprayhead androtatethecontrolthermostat knobfully counterclockwise
to the “OFF” position.
4. Remove the rear panel, feed the cord through the strain relief at the rear of the brewer, and connect it to the
terminal block. Replace the rear panel.
5. Connect the brewer to the power source and verify the voltage at the terminal block before proceeding.
Replace the front panel.
6. If plumbing is to be hooked up later, make sure that the brewer is disconnected from the power source. If
plumbing has been hooked up, the brewer is ready for Initial Set-Up.
USER NOTICES (cont.)
This equipment is to be installed to
comply with the Basic Plumbing Code of
the Building Officials and Code
Administrators International, Inc. (BOCA)
and the Food Service Sanitation Manual
of the Food and Drug Administration (FDA).
00656.0000
WARNING
HOT
WATER
12744.0000
120V.A.C.
NEUTRAL
WHITE
L1 BLACK
208 or 240
Volts A.C.
L2 RED
WHITE
NEUTRAL
L1 BLACK
120 V.A.C.
120 V.A.C.
(Revised November 1999)

Page 5
PLUMBING REQUIREMENTS
This brewer must be connected to a cold water system with operating pressure greater than 10 psi from a
1/2” or larger supply line. A shut-off valve should be installed in the line before the brewer. Install a regulator in
the line when pressure is greater than 90 psi to reduce it to 50 psi. The water inlet fitting is 1/4" flare.
NOTE-Bunn-O-Maticrecommends1/4"coppertubingforinstallationsoflessthan25feetfromthe1/2"orlarger
supply line. A tight coil of copper tubing in the water line will facilitate moving the brewer to clean the counter
top. Bunn-O-Maticdoesnotrecommendtheuseofasaddlevalvetoinstallthebrewer. Thesizeandshapeofthe
hole made in the supply line by this type of device may restrict water flow.
Plumbing Hook-Up
1. Makecertainthatthe1/4"femaleflarefittingon theshorttubefrom the outletofthewater strainerissecurely
attached to the male bulkhead fitting on the brewer.
2. Flush the water line and securely attach it to the 1/4" flare fitting on the strainer.
3. Turn on the water supply.
INITIAL SETUP
CAUTION - The brewer must be disconnected from the power source throughout the initial setup, except when
specified in the instructions.
1. Remove the front panel from the brewer.
2. Rotate the control thermostat knob fully counterclockwise to the "OFF" position and replace the panel.
3. Insert an empty funnel into the funnel rails.
4. Place a decanter containing a small amount of water on the warmer beneath the brew funnel.
5. Connect the brewer to the power source and place the On/Lower switch in the upper position.
6. Momentarilypressthestart switch. Approximately64ounces ofwaterwill flowinto thebrew tank. To fillthe
tank, it will be necessary to start two more brew cycles. Place the On/Lower switch in the lower position
when water starts flowing form the funnel into the decanter.
7. Disconnect the brewer from the power source and remove the front panel.
8. Rotate the control thermostat knob fully clockwise to the "ON" position and replace the panel.
9. Connect the brewer to the power source and wait for the water in the tank to heat to the proper temperature.
Some water will drip from the funnel during this time; this is due to expansion and should not occur thereaf-
ter.
10. Place an empty decanter under the funnel.
11. Place the On/Lower switch in the upper position and momentarily press the start switch. Empty the decanter
after water has stopped flowing from the funnel and return it to the warmer.
12. Allow the water in the tank to reheat to the proper temperature.
13. Momentarily press the start switch. Check the water volume in the decanter after water has stopped flowing
from the funnel. It should be 64 ounces.
14. If not, disconnect the brewer from the power source and remove the top lid.
15. Add or remove washers to the float on the level switch as required and replace the top lid. Adding washers
increases the volume, removing washers decreases it.
16. Repeat steps 12-15 until the proper water volume is achieved.
17A. Model SL:
The brewer is now ready for use in accordance with the coffee brewing instructions on page 6.
17B. Model SLF:
Momentarily press the hot water dispense switch a few times to clear any air from the dispense lines.
18. Allow the tank to fully reheat.
(Revised November 1999)
This equipment must be installed to comply with the Basic Plumbing Code of the Build-
ing Officials and Code Administrators International, Inc. (BOCA) and the Food Service
Sanitation Manual of the Food and Drug Administration (FDA).

Page 6
19. Pressthehotwaterswitchtodispenseexactly20ouncesofhotwaterandimmediatelystartabrewcycleinto
an empty graduated vessel.
20. Measure the brew water volume:
ifitismorethantheamountmeasuredin#16,removetherearpanel,turntheneedlevalveslightlyclockwise,
and replace the rear panel.
If it is less than the amount measured in #16, remove the rear panel, turn the needle valve slightly counter-
clockwise, and replace the rear panel.
21. Repeat steps 18-20 until the hot water refill rate is balanced with the dispense rate.
OPERATING CONTROLS
A. On/Lower Switch
Placing the switch in the upper position enables brewing and energizes the decanter warmer beneath the
funnel.
Placing the switch in the lower position cuts power to the warmer beneath the brew funnel and stops the
brew cycle. Stopping a brew cycle after it has been started will not stop the flow of water into the funnel until
the tank syphons down to its proper level.
B. Top Warmer Switch
Placing the switch in the upper position energizes the top warmer.
Placing the switch in the lower position cuts power to the top warmer.
C. Start Switch
Momentarily pressing this switch initiates a brew cycle when the On/Lower switch is in the upper position.
D. Hot Water Dispense Switch (Model SLF only)
Placing the switch in the lower position dispenses hot water and at the same time refills the tank. Dispens-
ing/refilling occurs for as long as the switch is held.
CLEANING
1. 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.
2. Check and clean the sprayhead. The sprayhead holes must always remain open.
3. Disconnect the brewer from the power source. Remove the sprayhead and insert the deliming spring (pro-
vided)allthe wayintothesprayheadtube. Wheninsertedproperly,nomorethan twoinchesofspringshould
be visible. Saw back and forth five or six times.
NOTE-Inhardwaterareas,thismayneedtobedonedaily. Itwillhelppreventlimingproblemsinthebrewerand
takes less than a minute.
COFFEE BREWING
1. Insert a BUNN® filter into the funnel .
2. Pour the fresh coffee into the filter and level the bed of grounds by gently shaking.
3. Slide the funnel into the funnel rails.
4. Place an empty decanter under the brew funnel.
5. Place the On/Lower switch in the upper position and momentarily press the start switch.
6. When brewing is completed, simply discard the grounds and filter.
INITIAL SET-UP (cont.)
(Revised November 1999)

Page 7
Problem
Equipment will not operate.
Brew cycle will not start.
Probable Cause
1. No power or incorrect voltage
1. No water
2. Water Strainer
3. Water Level Switch and Overflow
Safety Switch
Remedy
(A)Connectthebrewertothepower
source.
(B) Check the terminal block for the
proper voltages.
(C) Check circuit breaker/fuse.
Checkplumbingandshut-offvalves.
(A) Direction of flow arrow must be
pointing towards brewer.
(B) Remove the strainer and check
for obstructions. Clear or replace.
RefertoService-WaterLevelSwitch
andOverflowSafetySwitchfortest-
ing procedures. See page 23.
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,andrepairofelectricalequipmentshouldbeperformedonlybyqualifiedservicepersonnel.
• All electric components have 120 volt ac voltage on their terminals. Shorting of terminals or the application
of external voltages may result in equipment failure.
• Intermittent operation of electronic equipment is unlikely. Component 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.
• Solenoid removal requires interrupting the water supply to the valve. Damage may result if solenoids are
energized for more than ten minutes without a supply of water.
• The use of two wrenches is recommended whenever plumbing fittings are tightened or loosened. This will
help to avoid twists and kinks in the tubing.
• Make certain that all plumbing connections are sealed and electrical connections tight and isolated.
• Thisbrewerisheatedatalltimesunlessdisconnectedfromthepowersource. Keepawayfromcombustibles.
WARNING
• Exercise extreme caution when servicing electrical equipment.
• Disconnect the brewer from the power source when servicing, except when electrical tests are specified.
• Follow recommended service procedures
• Replace all protective shields or safety notices
(Added November, 1999)

Page 8
TROUBLESHOOTING (cont.)
Problem
Brew cycle will not start. (cont.)
Water flows into fill basin continu-
ously (On/Lower brew station
warmer switch "OFF").
Water flows into fill basin continu-
ously (On/Lower brew station
warmer switch "ON").
Water is not hot.
Decanter warmer is not hot.
Probable Cause
4. On/Lower Brew Station Warmer
Switch
5. Start Switch
6. Relay
7. Solenoid Valve
1. Solenoid Valve
1. Start Switch
1. Limit Thermostat
CAUTION
Donoteliminateorbypasslimitther-
mostat. Use only B.O.M. replace-
ment part #29329.1000
2. Control Thermostat
3. Tank Heater
1. Warmer Switches
2. Decanter Warmers
Remedy
Refer to Service - On/Lower Brew
Station Warmer Switch for testing
procedures. See page 15.
Refer to Service - Start Switch for
testing procedures. See page 16.
Refer to Service - Relay for testing
procedures. See page 21.
RefertoService-SolenoidValvefor
testing procedures. See page 17.
RefertoService-SolenoidValvefor
testing procedures. See page 17.
Refer to Service - Start Switch for
testing procedures. See page 16.
Refer to Service - Limit Thermostat
fortestingprocedures. Seepage17.
Refer to Service - Control Thermo-
stat for testing procedures. See
page 13.
Refer to Service - Tank Heater for
testing procedures. See page 22.
(A)TheWarmerSwitch(es)mustbe
in the "ON" position for the warmer
to operate.
(B) Refer to Service - Warmer
Switch(es) for testing procedures.
See pages 15.
RefertoService-Warmersfortest-
ing procedures. See pages 14.
(Added November, 1999)

Page 9
TROUBLESHOOTING (cont.)
Problem
Spitting or unusual steaming from
sprayhead.
Warmerplatestoohot,solenoidcoil
smoking, or water in tank heats ex-
cessively fast.
Inconsistent beverage level in de-
canter.
Dripping from sprayhead.
Probable Cause
1. Control Thermostat
2. Lime build-up
CAUTION
Tank and tank components should
be delimed regularly depending on
local water conditions. Excessive
mineral build-up on stainless steel
surfacescan initiate corrosive reac-
tions resulting in serious leaks.
1. Brewer wired to wrong voltage
1. Improper water pressure
2. Syphon system
3. Hot water Dispense flow adjust-
ment (SLF only)
1. Syphon system
2. Solenoid Valve
Remedy
Refer to Service - Control Thermo-
stat for testing procedures. See
page 13.
Inspectthetankassemblyforexces-
sive lime deposits. Delime as re-
quired.
Refer to Electrical Requirements -
Page 4.
Check the operating water pressure
to the brewer. It must be between
10 and 90 psi.
Water should flow freely from the
sprayhead and then stop abruptly.
Thebrewermustbelevelfromfront-
to-back to syphon properly.
Refer to Service - Hot Water Dis-
pense Valve - Page 19 and Inlet So-
lenoid Valve - Page 20.
Water should flow freely from the
sprayhead and then stop abruptly.
Thebrewermustbelevelfromfront-
to-back to syphon properly.
RefertoService-SolenoidValvefor
testing procedures. See page 17.
(Added November, 1999)

Page 10
TROUBLESHOOTING (cont.)
Problem
Nohot waterdispensedfrom faucet
(SLF only)
Probable Cause
1. Hot Water Switch
2. Hot Water Dispense Valve
3. Inlet Solenoid Valve (Faucet)
Remedy
Refer to Service - Hot Water Switch
fortestingprocedures. Seepage24.
Refer to Service - Hot Water Dis-
pense Valve for testing procedures.
See page 19.
Refer to Service - Inlet Solenoid
Valve (faucet) for testing proce-
dures. See page 20.
Beverage overflows decanter.
Weak beverage.
1. Beverage left in decanter
1. Type of paper filters
2. Coffee
3. Sprayhead
4. Funnel loading
5. Water temperature
The brew cycle should be started
only with an empty decanter under
the funnel.
BUNN®paperfiltersshouldbeused
for proper extraction.
A sufficient quantity of fine or drip
grind coffee should be used for
proper extraction.
B.O.M. sprayhead #01082.0000
should be used to properly wet the
bed of ground coffee in the funnel.
The BUNN® paper filter should be
centered in the funnel and the bed
of coffee leveled by gentle shaking.
Place a funnel over an empty de-
canter on the warmer beneath the
sprayhead. Place the On/Lower
brew station warmer switch in the
upper position, press the start
switch, and check the water tem-
perature immediately below the
sprayhead with an accurate ther-
mometer. The reading should not
beless than 195°F. Adjustthe con-
trolthermostatslightly clockwiseto
increase the water temperature.
(Added November 1999)

Page 11
TROUBLESHOOTING (cont.)
Problem
Brewer is making unusual noises.
Probable Cause
1. Solenoid Valve
2. Plumbing lines
3. Water supply
Remedy
The nut on top of the solenoid valve
must be tight or it will vibrate dur-
ing operation.
Plumbing lines should not rest on
the counter top.
(A) The brewer must be connected
to a cold water line.
(B) Water pressure to the brewer
must not be higher than 90 psi. In-
stallaregulatorifnecessarytolower
the working pressure to approxi-
mately 50 psi.
(Added November 1999)

Page 12
FIG. 1 ACCESS PANELS
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.
Component Access
WARNING - Disconnect the brewer from the power
sourcebeforetheremovalofanypanelorthereplace-
ment of any component.
Theoverflowsafetyswitch,warmerswitches,hot
water dispense valve(SLF only) and start switch are
located under the top cover or top warmer housing,
FIG.1, attached with four #6-32 slotted-head screws.
The solenoid valve, relay, control thermostat and
terminal block are located in the trunk. Access is
gained by removing the front access panel, FIG. 1 at-
tached with four #8-32 slotted-head screws
The inlet solenoid valve (SLF only), limit thermo-
stat, tank heater and tank “keep warm” heater are lo-
cated on the tank assembly. Access is gained by re-
moving the rear panel, FIG. 1 attached with four #8-
32 slotted head screws.
WARNING - Inspection, testing, and repair of electri-
cal equipment should be performed only by qualified
servicepersonnel. Thebrewershouldbedisconnected
from the power source when servicing, except when
electrical tests are required and the test procedure
specificallystates to connect the brewer to the power
source. Contents
Control Thermostat...............................................13
Warmer(s) ............................................................14
Warmer Switch(es)...............................................15
Start Switch..........................................................16
Limit Thermostat ..................................................17
Brew Solenoid Valve.............................................17
Hot Water Dispense Valve(optional) .....................19
Inlet Solenoid Valve (faucet-optional)...................20
Relay.....................................................................21
Tank Heater...........................................................22
Overflow Safety Switch.........................................23
Hot Water Switch (optional) .................................24
Replacement parts................................................25
Wiring Schematics............................................... 26
P1712
(Added November 1999)
10043.0000D3/97© 1988 BUNN-O-MATICCORPORATION
WHI
BLU
LIMIT
THERMOSTAT
SW.&
THERMOSTAT
TANKHEATER
N
BLK
L1
BLK
WHI
P1
P3
P2
P1,P2, & P3ARE PINSOF
APOLARIZEDTHREE-PIN
CONNECTOR.
GREEN
SCHEMATIC WIRINGDIAGRAMS
"KEEPWARM"HEATER
50W
WHI
TOPREAR
WARMER
100W
WHI
WHI
BLKBLU/BLK
TOPFRONT
WARMER
100W
WHI
BLKBRN/BLK
LOWERWARMER
100W
WHI
WHI
BLK
BLU/BLK
BRN/BLK
WHI
120VOLTSAC2WIRE
SINGLEPHASE
60HZ
1425W
WHI/VIO
!CAUTIONWARMERSANDSURFACESAREHOT
TOPFRONTON/LOWERSTART
TOPREARLOWERTOPFRONT
TOPREAR
WARNING
HOT
WATER

Page 13
FIG. 2 CONTROL THERMOSTAT
SERVICE (cont.)
Control Thermostat
Location:
The control thermostat is located inside the front
access panel, FIG. 2.
Totest the control thermostat, access will also be
neededtothe tank heater located in the bottom of the
tank assembly.
Test Procedure:
1. Disconnect the brewer from the power source.
2. Withavoltmeter,checkthevoltageacrosstheblue/
blackwireonthecontrolthermostatandthewhite
wire on the tank heater. Connect the brewer to
the power source. The indication must be 120
volts ac for two wire 120 volt models and three
wire 120/240 volt models.
3. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #4.
Ifvoltageisnotpresentasdescribed,refertotheWir-
ing Diagrams and check the brewer wiring harness.
4. With a voltmeter, check the voltage across the
black wire terminal of the control thermostat and
thewhitewireonthetankheaterwhenthecontrol
thermostat is turned "ON" (fully clockwise). Con-
nect the brewer to the power source. The indica-
tionmustbeasdescribedinstep2. Voltagemust
not be indicated across these terminals when the
thermostat is turned "OFF" (fully counterclock-
wise).
5. Disconnect the brewer from the power source.
Ifvoltageispresentasdescribed,thecontrolthermo-
stat is operating properly.
Ifvoltageisnotpresentasdescribed,replacethecon-
trol thermostat.
Removal and Replacement:
1. Remove the front access panel from the brewer
to gain access.
2. Remove both wires from the control thermostat
terminals.
3. Remove the thermostat bulb by firmly pulling-up
on the capillary tube at the tank lid. This will dis-
engage the grommet from the tank lid.
4. Remove the two #8-32 screws holding the con-
trol thermostat to the bracket.
5. Fasten the new control thermostat to the compo-
nent bracket.
NOTE- Makesurethatthecapillary tubeisaway from
any electrical termination and is not kinked.
6. Slide the grommet to the red mark on the capil-
lary tube.
7. Insertthebulbthroughtheholeinthetanklidand
press the grommet firmly and evenly so that the
groove in the grommet fits into the tank lid.
8. Carefully bend the capillary tube so that the tube
and bulb inside the tank are in a vertical position.
9. Refer to FIG. 3 when reconnecting the wires.
10. Readjust the control thermostat dial as required.
P1478
(Added November 1999)

Page 14
FIG. 4 WARMERS
FIG. 5 WARMER WIRING
SERVICE (cont.)
Location:
One of the warmers is beneath the brew funnel
and the other is on the top lid, FIG. 4.
Test Procedure:
1. Once the switch has been tested and switch fail-
ure has been eliminated, proceed as follows.
2. Disconnectthebrewerfromthepowersourceand
remove the #4-40 screws attaching the warmer
being tested.
3. Lift the warmer assembly from the brewer and
invert the warmer making the wire terminals ac-
cessible for testing.
4. Check for continuity from the switch to the white
wire at the warmer element.
If continuity is present as described, proceed to #5.
5. Check for continuity from the wire terminal of the
blue/black or violet wire to the warmer switch.
If continuity is present as described, proceed to #6.
If continuity is not present as described, refer to the
Wiring Diagrams and check the brewer wiring har-
ness.
6. Check for continuity across the two terminals on
the warmer.
If continuity is present as described, the warmer is
operating properly.
If continuity is not present as described, replace the
warmer.
Removal and Replacement:
1. Remove the #4-40 slotted-head screws holding
the warmer to the brewer
2. Lift the warmer assembly from the brewer.
3. Disconnect both wires from the warmer.
4. Refer to FIG. 5 when reconnecting the wires.
5. Placethenewwarmerintothebrewerandsecurely
attach it using the #4-40 screws.
WHI to Warmer Switch
BLU/BLK to Warmer
Switch
P1712
P1692
FIG. 3 THERMOSTAT WIRING
BLK to Terminal Block
BLU/BLK to Limit
Thermostat
(Added November 1999)
10043.0000D3/97©1988BUNN-O-MATICCORPORATION
WHI
BLU
LIMIT
THERMOSTAT
SW.&
THERMOSTAT
TANKHEATER
N
BLK
L1
BLK
WHI
P1
P3
P2
P1,P2,&P3AREPINSOF
APOLARIZEDTHREE-PIN
CONNECTOR.
GREEN
SCHEMATICWIRINGDIAGRAMS
"KEEPWARM"HEATER
50W
WHI
TOPREAR
WARMER
100W
WHI
WHI
BLKBLU/BLK
TOPFRONT
WARMER
100W
WHI
BLKBRN/BLK
LOWERWARMER
100W
WHI
WHI
BLK
BLU/BLK
BRN/BLK
WHI
120VOLTSAC2WIRE
SINGLEPHASE
60HZ
1425W
WHI/VIO
!CAUTIONWARMERSANDSURFACESAREHOT
TOPFRONTON/LOWERSTART
TOPREARLOWERTOPFRONT
TOPREAR
Lower Warmer
Top Warmer
VIO to On/Lower
Switch
WHI to Terminal
Block
Warmer(s)
Control Thermostat (cont.)
P2024

Page 15
FIG. 6 WARMER SWITCHES
FIG. 7 WARMER SWITCH WIRING
SERVICE (cont.)
Warmer Switch(es) If voltage is present as described the switch is oper-
ating properly.
If voltage is not present as described, replace the
switch.
Removal and Replacement:
1. Compress the clips inside the housing and gently
push the switch through the opening.
2. Remove the wires from the switch terminals.
3. Refer to FIG. 7 when reconnecting the wires.
4. Push the new switch firmly into the opening.
Location:
These switches are the two left switches on the
switch panel, FIG 6.
Test Procedure:
1. Locate the switch terminal with black wires.
2. Checkthevoltageacrossthisterminalandtheter-
minalon theindicator lampwithwhite wirewith a
voltmeter. Connect the brewer to the power
source. The indication must be 120 volts ac for
two wire 120 volt models and three wire 120/240
volt models.
3. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #4.
Ifvoltageisnotpresentasdescribed,refertotheWir-
ing Diagrams and check the brewer wiring harness.
4. Witha voltmeter, check the voltage across the re-
maining switch terminal and the terminal on the
indicator lamp with white wire when the switch is
in the upper position. Connect the brewer to the
power source. The indication must be as de-
scribed in step 2. Voltage must not be present
across these terminals in the lower position.
5. Disconnect the brewer from the power source.
P2012
(Added November 1999)
10043.0000D3/97©1988BUNN-O-MATICCORPORATION
WHI
BLU
LIMIT
THERMOSTAT
SW.&
THERMOSTAT
TANKHEATER
N
BLK
L1
BLK
WHI
P1
P3
P2
P1,P2,&P3AREPINSOF
APOLARIZEDTHREE-PIN
CONNECTOR.
GREEN
SCHEMATICWIRINGDIAGRAMS
"KEEPWARM"HEATER
50W
WHI
TOPREAR
WARMER
100W
WHI
WHI
BLKBLU/BLK
TOPFRONT
WARMER
100W
WHI
BLKBRN/BLK
LOWERWARMER
100W
WHI
WHI
BLK
BLU/BLK
BRN/BLK
WHI
120VOLTSAC2WIRE
SINGLEPHASE
60HZ
1425W
WHI/VIO
!CAUTIONWARMERSANDSURFACESAREHOT
TOPFRONT ON/ LOWERSTART
TOPREAR LOWER TOP FRONT
TOPREAR
Top Warmer
On/Lower Warmer
WHI to Top
Warmer, WHI to
On/Lower Switch
BLK to On/Lower
Switch
BLU/BLK to Top
Warmer
WHI to Top Warmer
Switch and WHI to
Terminal Block
(White Insert)
BLK to Top
Warmer and BLK
to Terminal Block
(Black Insert)
WHI/RED to
Overflow Safety
Switch and VIO to
Lower Warmer
P1590

Page 16
FIG. 8 START SWITCH
FIG. 9 START SWITCH WIRING
SERVICE (cont.)
Start Switch
Location:
The start switch is located on the far right of the
front switch panel , FIG 8.
Test Procedure:
1. Disconnectthebrewerfromthepowersourceand
remove the wires from both terminals of the start
switch.
2. Check for continuity across the two terminals on
the switch when it is held in the lower position.
Continuity must not be present across these ter-
minals 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.
Removal and Replacement:
1. Remove all wires from the switch terminals.
2. Compress the clips inside the housing and gently
push the switch through the opening.
3. Push the new switch into the opening and spread
the clips to hold the switch captive in the hous-
ing.
4. Refer to FIG. 9 when reconnecting the wires.
P2012
P1591
(Added November 1999)
10043.0000D3/97©1988BUNN-O-MATICCORPORATION
WHI
BLU
LIMIT
THERMOSTAT
SW.&
THERMOSTAT
TANKHEATER
N
BLK
L1
BLK
WHI
P1
P3
P2
P1,P2,&P3AREPINSOF
APOLARIZEDTHREE-PIN
CONNECTOR.
GREEN
SCHEMATICWIRINGDIAGRAMS
"KEEPWARM"HEATER
50W
WHI
TOPREAR
WARMER
100W
WHI
WHI
BLKBLU/BLK
TOPFRONT
WARMER
100W
WHI
BLKBRN/BLK
LOWERWARMER
100W
WHI
WHI
BLK
BLU/BLK
BRN/BLK
WHI
120VOLTSAC2WIRE
SINGLEPHASE
60HZ
1425W
WHI/VIO
!CAUTIONWARMERSANDSURFACESAREHOT
TOPFRONTON/LOWERSTART
TOPREARLOWERTOPFRONT
TOPREAR
BLK to Relay
(K5)
BRN/BLK to
Relay (K-A)

Page 17
P2014
FIG. 10 LIMIT THERMOSTAT
FIG. 11 LIMIT THERMOSTAT WIRING
SERVICE (cont.)
Limit Thermostat
2. Carefully slide the limit thermostat out from un-
der the retaining clip.
3. Carefully slide the new limit thermostat into the
retaining clip.
4. Refer to FIG. 11 when reconnecting the wires.
Location:
The limit thermostat is located on the back of the
tank assembly, FIG. 10.
Test Procedure:
1. Disconnect the brewer from the power source.
2. Checkvoltageacrosstheblackwirefromthelimit
thermostat and the white wire on the tank heater
terminal.Connectthebrewertothepowersource.
The indication must be 120 volts ac for two wire
120voltmodelsandthreewire120/240voltmod-
els.
3. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #4.
Ifvoltageisnotpresentasdescribed,refertotheWir-
ing Diagrams and check the brewer wiring harness.
4. Check for continuity across the limit thermostat
terminals.
Ifcontinuityispresentasdescribed,thelimitthermo-
stat is operating properly.
If continuity is not present as described, replace the
limit thermostat.
Removal and Replacement:
1. Remove both wires from the limit thermostat ter-
minals.
P1715
P1984
(Added November 1999)
BLK to Tank
Heater
BLU/BLK to Control
Thermostat
Solenoid Valve
Location:
The solenoid valve is located inside the front access
panel, near the bottom of the bracket, FIG. 12
FIG. 12 SOLENOID VALVE

Page 18
FIG. 13 SOLENOID VALVE WIRING
SERVICE (cont.)
Solenoid Valve(cont.)
Test Procedure:
1. With a voltmeter check the voltage across the
whiteand thewhite/redwires whentheOn/Lower
brew station warmer switch is in the upper posi-
tion and the start switch is pressed to the lower
position and released. Connect the brewer to the
power source. The indication must be 120 volts
ac for two wire 120 volt models and three wire
120/240 volt models,
2. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #3.
Ifvoltageisnotpresentasdescribed,refertotheWir-
ing Diagrams and check the brewer wiring harness.
3. Remove all wires from the coil. Check for conti-
nuity across the solenoid valve coil terminals.
If continuity is present as described, reconnect the
white and the white/red wires and proceed to #4.
If continuity is not present as described, replace the
solenoid valve.
4. Check the solenoid valve for coil action. Connect
the brewer to the power source, place the On/
Lower brew station warmer switch in the upper
position, press and release the start switch. Lis-
ten carefully in the vicinity of the solenoid valve
for a "clicking" sound as the coil magnet attracts
andafterlifting ofthe levelfloat switch,repels the
plunger.
5. Disconnect the brewer from the power source.
If the sound is heard as described and water will not
passthroughthesolenoidvalve,theremaybeablock-
ageinthewaterlinebeforeorafterthesolenoidvalve
or,thesolenoidvalvemayrequireinspectionforwear,
and removal of waterborne particles.
If the sound is not heard as described, replace the
solenoid valve.
P1588
(Added November 1999)
Removal and Replacement:
1. Disconnect the brewer from the power source.
2. Turn off the water supply to the brewer.
3. Remove the front access panel to gain access.
4. Disconnect all wires from the solenoid valve.
5. Disconnect the water lines to and from the sole-
noid valve.
6. Remove the two #8-32 screws which hold the
solenoid valve and mounting bracket to the com-
ponent bracket.
7. Lift out the solenoid valve and bracket. Remove
the bracket from the solenoid valve and save to
mount the new valve.
8. Securely install the new solenoid valve to the
mountingbracketwithtwo#10-32screws.Check
the direction of flow arrow on the valve. It must
be pointing toward the tank inlet tube.
9. Securely attach the valve and bracket to the com-
ponent bracket using the two #8-32 screws.
10. Securely fasten the water lines to and from the
solenoid valve.
11. Refer to FIG. 13 when reconnecting the wires.
WHI/GRN to
Brew Timer
WHI/RED to
ON/OFF Switch
Models ST & STA
WHI/RED to Relay
(K7)
WHI to Relay (K-B)

Page 19
SERVICE (cont.)
HOT WATER DISPENSE VALVE (OPTIONAL)
FIG. 14 HOT WATER DISPENSE VALVE
P2021
Location:
The hot water dispense valve is located under the
topcover or top warmerhousingand to the leftofthe
switches, FIG. 14.
Test Procedure:
1. With a voltmeter check the voltage across the
whiteand the white/violet wires when the hot wa-
ter dispense switch is pressed to the lower posi-
tion and held. Connect the brewer to the power
source. The indication must be 120 volts ac for
two wire 120 volt models and three wire 120/240
volt models.
2. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #3.
Ifvoltageisnotpresentasdescribed,refertotheWir-
ing Diagrams and check the brewer wiring harness.
3. Remove all wires from the coil. Check for conti-
nuity across the solenoid valve coil terminals.
If continuity is present as described, reconnect the
white and the white/violet wires and proceed to #4.
If continuity is not present as described, replace the
solenoid valve.
4. Check the solenoid valve for coil action. Connect
thebrewertothepowersource,placethehotwater
dispenseswitchinthelowerpositionandrelease. FIG. 15 HOT WATER DISPENSE
VALVE WIRING
P2022
WHI to Inlet Solenoid
Valve(faucet) and WHI
to On/Lower Switch
WHI/VIO to Inlet
Solenoid Valve (faucet)
and WHI/VIO to Hot
Water Switch (Faucet)
(Added November 1999)
Listencarefullyinthevicinityofthesolenoidvalve
for a “clicking” sound as the coil magnet attracts
and repels the plunger.
5. Disconnect the brewer from the power source.
If the sound is heard as described and water will not
passthroughthesolenoidvalve,theremaybeablock-
ageinthewaterlinebeforeorafterthesolenoidvalve
or,thesolenoidvalvemayrequireinspectionforwear,
and removal of waterborne particles.
If the sound is not heard as described, replace the
solenoid valve.
Removal and Replacement:
1. Disconnect the brewer from the power source.
2. Turn off the water supply to the brewer.
3. Remove the top cover or top warmer housing to
gain access.
4. Drain water from tank until level is below water
outlet tube.
5. Disconnect the water lines to and from the sole-
noid valve.
6. Remove the two #8-32 screws which hold the
solenoid valve and mounting bracket to the com-
ponent bracket.
7. Lift out the solenoid valve and bracket. Remove
the bracket from the solenoid valve and save to
mount the new valve.
8. Securely install the new solenoid valve to the
mountingbracketwithtwo#10-32screws.Check
the direction of flow arrow on the valve. It must
be pointing toward the dispense tube.
9. Securely attach the valve and bracket to the com-
ponent bracket using the two #8-32 screws.
10. Securely fasten the water lines to and from the
solenoid valve.
11. Refer to FIG. 15 when reconnecting the wires.

Page 20
SERVICE (cont.)
INLET SOLENOID VALVE (FAUCET - OPTIONAL)
FIG. 16 INLET SOLENOID VALVE
(FAUCET)
P2021
Location:
The Inlet Solenoid Valve (faucet) is located inside
the rear access panel, FIG. 16.
Test Procedures:
1. With a voltmeter check the voltage across the
whiteand the white/violet wires when the hot wa-
ter dispense switch is pressed to the lower posi-
tion and held. Connect the brewer to the power
source. The indication must be 120 volts ac for
two wire 120 volt models and three wire 120/240
volt models.
2. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #3.
Ifvoltageisnotpresentasdescribed,refertotheWir-
ing Diagrams and check the brewer wiring harness.
3. Remove all wires from the coil. Check for conti-
nuity across the solenoid valve coil terminals.
If continuity is present as described, reconnect the
white and the white/violet wires and proceed to #4.
If continuity is not present as described, replace the
solenoid valve.
4. Check the solenoid valve for coil action. Connect
thebrewertothepowersource,placethehotwater
dispenseswitchinthelowerpositionandrelease.
Listencarefullyinthevicinityofthesolenoidvalve
for a “clicking” sound as the coil magnet attracts
and repels the plunger.
5. Disconnect the brewer from the power source.
P2022
FIG. 17 INLET SOLENOID
VALVE WIRING
WHI/VIO to Hot Water
Dispense Valve
WHI to Hot Water
Dispense Valve
(Added November 1999)
If the sound is heard as described and water will not
passthroughthesolenoidvalve,theremaybeablock-
ageinthewaterlinebeforeorafterthesolenoidvalve
or,thesolenoidvalvemayrequireinspectionforwear,
and removal of waterborne particles.
If the sound is not heard as described, replace the
solenoid valve.
Removal and Replacement:
1. Disconnect the brewer from the power source.
2. Turn off the water supply to the brewer.
3. Remove the rear access panel to gain access.
4. Disconnect all wires from the solenoid valve.
5. Turn the needle valve handle clockwise to close
the needle valve.
6. Disconnect the water lines to and from the sole-
noid valve.
7. Remove the two #8-32 screws which hold the
solenoid valve and mounting bracket to the com-
ponent bracket.
8. Lift out the solenoid valve and bracket. Remove
the bracket from the solenoid valve and save to
mount the new valve.
9. Securely install the new solenoid valve to the
mountingbracketwithtwo#10-32screws.Check
the direction of flow arrow on the valve. It must
be pointing toward the needle valve.
10. Securely attach the valve and bracket to the com-
ponent bracket using the two #8-32 screws.
11. Securely fasten the water lines to and from the
solenoid valve.
12. Refer to FIG. 17 when reconnecting the wires.
13. Refer to Initial Set-Up for readjustment of the
needle valve (steps 18-20).