CEZ, CEZF,
CDBC, CDBCF
Airpot,
Thermal Carafe &
Thermal Server Brewers
DISCONTINUED VERSION
The information in this manual
OT
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CES A R
CAUTION :
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BUNN
is no longer current.
BUNN
CE
WARNING
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Y PANEL OR
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PONENT!
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DISCO
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REPLACEMENT OF ANY COM
OPERATING & SERVICE MANUAL
BUNN-O-MATIC CORPORATION
POST OFFICE BOX 3227
SPRINGFIELD, ILLINOIS 62708-3227
PHONE: (217) 529-6601 FAX: (217) 529-6644
29253.0000F 02/04 ©1999 Bunn-O-Matic Corporation
www.bunnomatic.com
INTRODUCTION
This equipment will automatically brew a half-gallon batch of coffee into an awaiting server at the press of a
button. A hot water faucet may be included for allied beverage use. Most functions of the brewer are digitally
controlled. It is only for indoor use on a sturdy counter or shelf.
CONTENTS
Introduction & Warranty .................................................................................... 2
User Notices ...................................................................................................... 3
Electrical & Plumbing Requirements ................................................................. 4
Operating Controls............................................................................................. 5
Initial Set-Up, Coffee Brewing, & Cleaning......................................................... 6
CEZ-APS/TS/TSR Adjustments & Optional Settings .......................................... 7
CDBC-APS/TC/TS/TSR Adjustments & Optional Settings .................................. 8
Water Sensing Threshold Adjustment Procedure .............................................. 9
Pulse Brew Setup Procedure ............................................................................. 9
Troubleshooting ............................................................................................... 10
Service............................................................................................................. 21
Wiring Diagrams.............................................................................................. 32
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) Compressors on refrigeration equipment: 5 years parts and 1 year labor.
4) Grinding burrs on coffee grinding equipment to grind coffee to meet original factory screen sieve analysis: parts and labor for 3 years
or 30,000 pounds of coffee, whichever comes first.
These warranty periods run from the date of installation BUNN warrants that the equipment manufactured by it will be commercially
free of defects in material and workmanship existing at the time of manufacture and appearing within the applicable warranty period.
This warranty does not apply to any equipment, component or part that was not manufactured by BUNN or that, in BUNN’s judgment,
has been affected by misuse, neglect, alteration, improper installation or operation, improper maintenance or repair, damage or
casualty. This warranty is conditioned on the Buyer 1) giving BUNN prompt notice of any claim to be made under this warranty by
telephone at (217) 529-6601 or by writing to Post Office Box 3227, Springfield, Illinois 62708-3227; 2) if requested 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 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.
If BUNN determines in its sole discretion that the equipment does not conform to the warranty, BUNN, at its exclusive option while the
equipment is under warranty, shall either 1) provide at no charge replacement parts and/or labor (during the applicable parts and labor
warranty periods specified above) to repair the defective components, provided that this repair is done by a BUNN Authorized Service
Representative; or 2) shall 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, AT BUNN’S SOLE OPTION AS SPECIFIED HEREIN, TO
REPAIR, REPLACEMENT OR REFUND.
In no event shall BUNN 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, incidental or consequential damages.
BUNN, CDBC-APS, CDBCF-TS, CDBCF-TC and CDBC-TSR are either trademarks or registered trademarks of Bunn-O-Matic Corporation.
Page 2
29253 021604
USER NOTICES
Carefully read and follow all notices in this manual and on the equipment. All labels on the equipment should
be kept in good condition. Replace any unreadable or damaged labels.
# 00986.0000
# 00656.0000
# 00658.0000
# 10044.0000
Page 3
29253 011900
ELECTRICAL REQUIREMENTS
CAUTION - The brewer must be disconnected from the power source until specified in
Model 15 has an attached cordset and requires 2-wire grounded service rated 120 volts ac, 15 amp, single
phase, 60 Hz.
Initial Set-Up.
WHITE
NEUTRAL
L1 BLACK
120V.A.C.
Model 20 requires 2-wire, grounded service rated
120 volts ac, 20 amp, single phase, 60 Hz. Proceed as
follows:
Model 35 requires 3-wire, grounded service rated
120/208 or 120/240 volts ac, 20 amp, single phase, 60
Hz. Proceed as follows:
L2 RED
WHITE
NEUTRAL
L1 BLACK
120V.A.C.
208 or 240V.A.C.
120V.A.C.
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. Remove the front panel beneath the sprayhead.
4. Feed the cord through the strain relief and connect it to the terminal block.
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 be sure the brewer is disconnected from the power source. If plumbing
has been hooked up, the brewer is ready for Initial Set-Up.
PLUMBING REQUIREMENTS
These brewers must be connected to a cold water system with operating pressure between 5 and 90 psi (34.5
and 620 kPa) for CDBC models and 20 and 90 psi (138 and 620 kPa) for CEZ models 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 (620 kPa) to reduce it to 50 psi (345 kPa). The water inlet fitting is 3⁄8" flare. Bunn-O-Matic
does not recommend the use of a reverse-osmosis or deionized water supply to this equipment.
NOTE - Bunn-O-Matic recommends 1⁄4" copper tubing for installations of less than 25 feet and 3⁄8" for more than
25 feet from the 1⁄2" water supply line. A tight coil of copper tubing in the water line will facilitate moving the brewer
to clean the countertop. Bunn-O-Matic does not recommend the use of a saddle valve to install the brewer. The
size and shape of the hole made in the supply line by this type of device may restrict water flow.
This equipment must 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).
Plumbing Hook-Up
1. Flush the water line.
2. Securely attach it to the flare fitting at the rear of the brewer.
3. Turn on the water supply.
Page 4
29253 091603
OPERATING CONTROLS
Model CEZ-APS/TS/TSR
ON/OFF SWITCH
Placing the "ON/OFF" switch in the "ON" upper position enables the
brew circuit, and energizes the tank refill circuit. Placing the switch
in the "OFF" lower position stops tank refilling and brewing. Stopping a brew cycle after it has been started will not stop the flow of
water into the server until the funnel is empty.
NOTE – Hot water will be available at the faucet in a limited amount
P1910
when the switch is in the "OFF" position because the tank will not
refill.
BREW SWITCH
Momentarily pressing and releasing the switch starts a brew cycle when the "ON/OFF" switch is in the "ON" upper
position.
NOTE – The "ON/OFF" switch must be in the "ON" upper position to initiate and complete a brew cycle.
READY INDICATOR
This indicator glows when the preselected brew water temperature has been achieved.
Model CDBC-APS/TC/TS/TSR
ON/OFF SWITCH
Pressing the "ON/OFF" switch (indicator glowing) enables the brew
circuit and energizes the tank refill circuit. Pressing the switch again
(indicator not glowing) stops tank refilling and brewing. Stopping a
brew cycle after it has been started will not stop the flow of water into
the server until the funnel is empty.
NOTE – Hot water will be available at the faucet in a limited amount
when the "ON/OFF" indicator is not glowing because the tank will not
P1911
refill.
BREW SWITCH
Momentarily pressing and releasing the switch starts a brew cycle when the "ON/OFF" indicator is glowing.
NOTE – The "ON/OFF" indicator must be glowing to initiate and complete a brew cycle.
READY INDICATOR
This indicator glows when the preset temperature has been achieved. The word "NOT" above "READY" will glow
in all other instances.
TEMPERATURE INDICATORS (Feature disabled from the factory – refer to page 8.)
The indicator glows to communicate the brew water temperature. Two indicators will glow when the
temperature is between them.
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29253 111103
INITIAL SET-UP
1. Insert an empty funnel into the funnel rails.
2. Place an empty server under the funnel.
3. Connect the brewer to the power source.
4. Model CDBC-APS/TC/TS/TSR – Press the "ON/OFF" switch (indicator glowing).
Model CEZ-APS/TS/TSR – Place the "ON/OFF" switch in the "ON" upper position.
5. Water will flow into the tank and stop when the tank is filled to its capacity.
6. Wait approximately twenty minutes for the water in the tank to heat to the proper temperature.
7. Place a small vessel beneath the faucet and open the faucet handle. Release it when you hear the tank refilling.
8. Model CDBC-APS/TC/TS/TSR – Press the "ON/OFF" switch (indicator glowing) then momentarily press and
release the "BREW" switch.
Model CEZ-APS/TS/TSR – Place the "ON/OFF" switch in the "ON" upper position then momentarily press and
release the "BREW" switch.
9. Allow the cycle to finish and measure the amount of water in the server. It should be 64 ounces ± 2. Refer
to the adjustments section of this manual should the volume need to be increased or decreased.
The brewer is now ready for use in accordance with the coffee brewing instructions below.
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 server beneath the funnel.
5. Model CDBC-APS/TC/TS/TSR – Press the "ON/OFF" switch (indicator glowing) then momentarily press and
release the "BREW" switch.
Model CEZ-APS/TC/TS/TSR – Place the "ON/OFF" switch in the "ON" upper position then momentarily press
and release the "BREW" switch.
6. When brewing is completed, simply discard the grounds and filter.
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.
Page 6
29253 111103
CEZ-APS/TS/TSR ADJUSTMENTS & OPTIONAL SETTINGS
IMPORTANT: The tank must be full and fill solenoid shut off prior to making these adjustments.
Adjusting Brew Volumes
The brewer is factory set to deliver 64 ounces
± 2 for each brew cycle.
BREW VOLUME SET-UP: Use the following steps
when the setting is unknown or a different circuit
board is being installed.
1. Place an empty funnel in the funnel rails and
an empty server or graduated vessel beneath the funnel.
2. Place the "ON/OFF" switch in the "ON", upper
position.
3. Press and hold the brew start button until
P1864
you hear the brew solenoid click on-and-off
three times (approximately 5 seconds). Release the button.
4. Allow the cycle to continue until the desired
amount of water is dispensed and then turn
"OFF" the brewer.
The brewer is now set to dispense this amount
of water for each subsequent brew cycle.
P1865
Page 7
To increase the amount of water for each
brew cycle place an empty funnel in the funnel
rails and an empty server or graduated vessel
beneath the funnel. Place the "ON/OFF" switch in
the "ON", upper position. Press and hold the
"BREW" switch until you hear the solenoid click
on-and-off three times (approximately 5 seconds), then release the "BREW" switch. Momentarily press and release the "BREW" switch once
for each ounce (approximate) of water to be
added to the prior setting and allow the brew
cycle to finish.
To decrease the amount of water for each
brew cycle place an empty funnel in the funnel
rails and an empty server or graduated vessel
beneath the funnel. Place the "ON/OFF" switch
in the "ON", upper position. Momentarily press
and release the "BREW" switch once for each
ounce (approximate) of water to be removed
from the existing setting. Press and hold the
"BREW" switch until you hear the solenoid click
on-and-off three times (approximately 5 seconds), then release the "BREW" switch and allow the cycle to finish.
29253 071599
CDBC-APS/TC/TS/TSR ADJUSTMENTS & OPTIONAL SETTINGS
P1912
Setting Brew Temperature
The brewer is factory set to brew at 200°F(95°C). To change this setting, press and hold the "HIDDEN" switch
beneath the "®". The word "TEMP" above the "ON/OFF" switch will glow to correspond with the temporary function
change of this switch. Repeatedly press and release the "ON/OFF" switch until one of the bank of temperature
indicators shows the approximate desired temperature. When two indicators are glowing, the temperature is
approximately the number between them.
Displaying Brew Temperature
The brewer is factory set with the temperature display disabled. To change this setting, press and hold the "ON/
OFF" switch and the "HIDDEN" switch beneath the "®" for five seconds, the entire bank of temperature indicators
will glow. Release both switches. Pressing and releasing the "ON/OFF" switch will toggle between turning the entire
bank of temperature indicators on-or-off, signifying the "ON" or "OFF" condition of this display. Wait for a few
seconds, the brewer will maintain this last setting.
Setting Brew Lockout
The brewer is factory set with the brew lockout disabled. Brew lockout prevents starting a brew cycle if the ready
indicator is not glowing. When an attempt at brewing cannot be allowed, the word "NOT" and "LOCKOUT" flash for
three seconds to indicate the reason the brew can't begin. To change the condition of the brew lockout, press and
hold the "HIDDEN" switch beneath the "®" and momentarily press the "BREW" switch.
IMPORTANT: The tank must be full and fill solenoid shut off prior to making these adjustments.
Adjusting Brew Volumes
The brewer is factory set to deliver 64 ounces ± 2 for each brew cycle.
BREW VOLUME SET-UP: Use the following steps when the setting is unknown or a different circuit board is being
installed.
1. Place an empty funnel in the funnel rails and an empty server or graduated vessel beneath the funnel.
2. Place the "ON/OFF" switch in the "ON", upper position.
3. Press and hold the brew start button until you hear the brew solenoid click on-and-off three times
(approximately 10 seconds). Release the button.
4. Allow the cycle to continue until the desired amount of water is dispensed and then turn "OFF" the brewer.
The brewer is now set to dispense this amount of water for each subsequent brew cycle.
To increase the amount of water for each brew cycle place an empty funnel in the funnel rails and an empty
server or graduated vessel beneath the funnel. Press the "ON/OFF" switch. Press and hold the "BREW" switch until
you hear the solenoid click on-and-off three times (approximately 10 seconds), then release the "BREW" switch.
Momentarily press and release the "BREW" switch once for each ounce (approximate) of water to be added to the
prior setting and allow the brew cycle to finish.
To decrease the amount of water for each brew cycle place an empty funnel in the funnel rails and an empty
server or graduated vessel beneath the funnel. Press the "ON/OFF" switch. Momentarily press and release the
"BREW" switch once for each ounce (approximate) of water to be removed from the existing setting. Press and
hold the "BREW" switch until you hear the solenoid click on-and-off three times (approximately 10 seconds),
then release the "BREW" switch and allow the cycle to finish.
Page 8
29253 111103
CDBC-APS/TC/TS/TSR ADJUSTMENTS & OPTIONAL SETTINGS (cont)
Water Sensing Threshold Adjustment Procedure
1. Make sure the tank is full of water to be used for calibration. The water must be in contact with the refill probe.
2. Unplug the brewer from the power source, then press and hold the BREW button while power is reapplied.
3. Continue pressing the BREW button until the READY indicator begins to flash. Release the BREW button and
then press it again momentarily.
4. The new calibration is automatically completed within a few seconds. If the water is too pure for use with the
brewer, the READY indicator will flash very rapidly and the old calibration will be retained.
Pulse Brew Setup Procedure
The pulse brew parameters (initial fill time, off times, and remaining on times) are entered using the following
set-by-example process.
1. First set the brew volume using the standard procedure in
2. Position an empty container under the sprayhead. Allow the tank to finish refilling. Make sure that the READY
lamp is on, or that the BREW LOCKOUT function is turned off.
3. Press and hold the OFF/ON button. The brew valve will turn on after 10 seconds. Release the button. This begins
the initial on-time setting. When the spray has continued for the desired time, momentarily press the OFF/ON
button.
4. The spray is now stopped and the off time setting has begun. Press the OFF/ON button momentarily to end
the off time.
5. The spray is now on again and the remaining on time setting has begun. Press the OFF/ON button momentarily
at the end of the desired remaining on time.
6. The setup is now complete and the parameters are stored in memory. The spray will continue the off and on
cycles until the brew volume of step 1 is complete. Pressing the OFF/ON button again will terminate the brewing
cycle, with the parameters stored in memory.
7. If only a preinfusion is desired, i.e. an initial on time followed by one off period, use the same procedure, but
stop after step 4 and allow the brew to finish the volume set in step 1. This will store the initial on time and off
time in memory.
Brew Volume Setup.
Procedure for Disabling Pulse Brew or Preinfusion:
1. Position an empty container under the sprayhead. Allow the tank to finish refilling. Make sure that the READY
lamp is on, or that the BREW LOCKOUT function is turned off.
2. Press and hold the OFF/ON button. The brew valve will turn on after 10 seconds. Release the button.
3. Allow the spray to continue and press no buttons until spray stops. The pulse and preinfusion functions are
now disabled.
NOTE: When the brewer has been set up for pulse or preinfusion, the adjustment of brew volume is done the same
as always and has no effect on the pulse brew parameters. The pulsing is temporarily disabled while adjusting the
brew volume and automatically returns during normal brewing.
Page 9
29253 111103
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.
• 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.
• This brewer is heated at all times. Keep away from combustibles.
WARNING –•Exercise extreme caution when servicing electrical equipment.
• Unplug the brewer when servicing, except when electrical tests are specified.
• Follow recommended service procedures.
• Replace all protective shields or safety notices.
Before troubleshooting this brewer, check for the following:
A. Control Boards (CDBC-APS/TC/TS/TSR)
1. Make sure ribbon cable is properly attached to the control board (ALL PINS INSERTED INTO PLUG).
2. Make sure there is a nylon insulating washer under each screw head that holds the control board to the plastic
front end cap. This is important for proper operation.
B. Control Boards (CEZ-APS/TS/TSR)
Locate J6 connector on control board. If jumper is across pins 1 & 2, board is set up to operate tea brewer or
a brewer that DOES NOT use a water level probe. If jumper is across pins 2 & 3, board is set up to operate a
coffee brewer or a brewer that uses a water level probe. Look at the bottom side of the control board. Pin 1 of
connector J6 is marked by a square solder pad on the foil side of the board and pins 2,3 & 4 are marked by a
round solder pad.
C. Control Boards (CDBC-APS/TC/TS/TSR & CEZ-APS/TS/TSR)
Make sure before servicing brewer that voltage is present at control board.
On CDBC-APS/TC/TS/TSR models, observe if indicator light is glowing on the control panel. If so, proceed with
testing. If not, check for voltage across pins 1 & 2 of the ten pin J1 connector (black and white wires). If voltage
is present, replace the control board. If voltage is not present, check wiring and voltage across terminal block
(black and white). Correct the problem and retest before proceeding with testing.
On CEZ-APS/TS/TSR models, check for voltage across pins 1 & 7 of the eight pin J1 connector (black and white
wires). If voltage is present, proceed with testing. If voltage is not present, check wiring and voltage across
terminal block (black and white). Correct the problem and retest before proceeding with testing.
Page 10
29253 091603
TROUBLESHOOTING (cont.)
REFILL CIRCUIT
PROBABLE CAUSE REMEDYPROBLEM
Will not fill or refill
1. Power off to brewer (CDBC-APS/
TC/TS/TSR & CEZ-APS/TS/TSR)
2. Water shut off (CDBC-APS/TC/
TS/TSR & CEZ-APS/TS/TSR)
3. Display flashing (CDBC-APS/TC/
TS/TSR) or ready light flashing
(CEZ-APS/TS/TSR)
4. ON/OFF Switch (CDBC-APS/TC/
TS/TSR & CEZ-APS/TS/TSR)
5. Lime build up on Probe (CDBCAPS/TC/TS/TSR & CEZ-APS/TS/
TSR)
6. Refill Valve or Control Board
(CDBC-APS/TC/TS/TSR & CEZAPS/TS/TSR)
Press ON/OFF switch on control
panel to determine if power is ON.
Make sure water is ON.
Brewer has shut down due to
malfunction (See Diagnostic Chart
in manual, Page 19, or under top lid
of brewer).
Make sure ON/OFF Switch is "ON"
and indicator is lit.
Remove the Probe and check for
lime deposit on tip. Clean and
reinstall.
Disconnect the brewer from the
power source and remove wires
from refill valve coil. Check for continuity across the terminals of the
solenoid coil. If continuity is not
present, replace the refill valve (See
page 30). If continuity is present,
the valve may be stuck closed. Shut
water off to brewer. Set the ON/OFF
switch to the "OFF" position. Open
the faucet and drain water down in
the tank until flow stops or slows to
a trickle. Attach a voltmeter to the
terminals of the refill solenoid. Connect the brewer to the power source.
Press the switch "ON". Within five
seconds, voltage should be present
at the solenoid terminals. If voltage
is not present, refer to the wiring
diagrams and check the wiring harness.
Fill or refill does not shut "OFF"
(ON/OFF Switch "ON")
7. Water is too conductive for proper
operation when using the factory
setting of sensing threshold. (CDBCAPS/TC/TS/TSR)
1. Lime build up on probe (CDBCAPS/TC/TS/TSR & CEZ-APS/TS/
TSR)
Page 11
Reset the
old Adjustment Procedures
Water Sensing Thresh-
on page
9.
Remove Probe and check for lime
deposits on tip. Clean and reinstall.
29253 111103
TROUBLESHOOTING (cont.)
REFILL CIRCUIT (cont.)
Fill or refill does not shut "OFF" (ON/
OFF Switch "ON") (cont)
PROBABLE CAUSE
2a. Water Level Probe Sensing
System (CDBC-APS/TS/TSR)
2b. Water Level Probe Sensing System (CEZ-APS/TC/TS/TSR)
REMEDYPROBLEM
A) Disconnect the brewer from the
power source. Disconnect the J3
connector from the control board.
Check for continuity from the nut
on top of the level probe to pin 1 of
the plug, continuity should be
present. Pull the temperature probe
up about an inch from the grommet.
Check for continuity from the
outside surface of the temperature
probe and pin 4 of the plug,
continuity should be present.
Connect the J3 plug to the control
board and proceed to step 3.
B) Disconnect the brewer from the
power source. Disconnect the J5
connector from the control board.
Check for continuity from the nut
on top of the level probe to pin 5 of
the plug, continuity should be
present. Pull the temperature probe
up about an inch from the grommet. Check for continuity from the
outside surface of the temperature
probe and pin 2 of the plug, continuity should be present. Connect
the J5 plug to the control board and
proceed to step 3.
Fill or refill does not shut "OFF" (ON/
OFF Switch "OFF")
3. Refill valve or control board
(CDBC-APS/TC/TS/TSR & CEZAPS/TS/TSR)
4. Water is too conductive for proper
operation when using the factory
setting of sensing threshold. (CDBCAPS/TC/TS/TSR)
1. Refill valve or control board
(CDBC-APS/TC/TS/TSR & CEZAPS/TS/TSR)
Page 12
Press ON/OFF switch to "ON" (Indicator lamp should be lit). If water
continuously flows out of air vent
tube, disconnect the brewer from
the power source. If water flow
stops, replace the control board. If
water flow does not stop, repair or
replace the refill solenoid. (See page
30)
Reset the
Adjustment Procedures
Water Sensing Threshold
on page 9.
If water continuously flows out of
air vent tube, disconnect the brewer
from the power source. If water
flow does not stop, repair or replace
the refill solenoid. If the valve closes
when power is removed, replace
the control board. (See pages 21 &
22)
29253 111103
TROUBLESHOOTING (cont.)
HEATING CIRCUIT
PROBLEM PROBABLE CAUSE
Water does not heat to proper
temperature
1. Display flashing (CDBC-APS/TC/
TS/TSR) or ready light flashing
(CEZ-APS/TS/TSR)
IMPORTANT: Make sure no temperature tests are taken before the
ready light is "ON". Tank temperature must be stabilized before read-
2. Water not touching temperature
probe
ings are taken.
3a. Dry Plug In Probe Sensing Sys-
tem (CDBC-APS/TC/TS/TSR)
REMEDY
Brewer has shut down due to
malfunction (See Diagnostic Chart
in manual, Page 19, or under top
lid).
Remove probe and grommet. Look
into hole on tank lid. Water must be
within one inch from top of tank.
A) Disconnect the brewer from the
power source. Disconnect the J3
connector from the control board.
Check for continuity from the tank
mounting screw where the green
wire mounts, to pin 2 of the plug,
continuity should be present. Pull
the temperature probe up about an
inch from the grommet. Check for
continuity from the outside surface
of the temperature probe and pin 4
of the plug, continuity should be
present. Connect the J3 plug to the
control board and proceed to step
4a.
3b. Dry Plug In Probe Sensing Sys-
tem (CEZ-APS/TS/TSR)
Page 13
B) Disconnect the brewer from the
power source. Disconnect the J5
connector from the control board.
Check for continuity from the tank
mounting screw where the green
wire mounts, to pin 4 of the plug,
continuity should be present. Pull
the temperature probe up about an
inch from the grommet. Check for
continuity from the outside surface
of the temperature probe and pin 2
of the plug, continuity should be
present. Connect the J5 plug to the
control board and proceed to step
4b.
29253 111103
TROUBLESHOOTING (cont.)
HEATING CIRCUIT (cont.)
PROBLEM PROBABLE CAUSE REMEDY
Water does not heat to proper
temperature (cont.)
IMPORTANT: Make sure no temperature tests are taken before the
ready light is "ON". Tank temperature must be stabilized before readings are taken.
4a. Temperature Probe (CDBC-APS/
TC/TS/TSR)
4b. Temperature Probe (CEZ-APS/
TS/TSR)
A) Remove the probe from the grommet and submerge in a water bath
of approximately 70°F(21°C). Connect an ohmmeter to pins 3 and 4 of
the J3 connector. At 60°F(16°C)
the reading should be 15.3k ± 2k
OHMS, at 70°F(21°C) the reading
should be 11.8k ± 2k OHMS, and at
80°F(27°C) the reading should be
9.3k ± 2k OHMS. If the probe is
within these parameters, reconnect
the J3 plug to the control board.
B) Remove the probe from the grommet and submerge in a water bath
of approximately 70°F(21°C). Connect an ohmmeter to pins 2 and 3 of
the J5 connector. At 60°F(16°C)
the reading should be 15.3k ± 2k
OHMS, at 70°F(21°C) the reading
should be 11.8k ± 2k OHMS, and at
80°F(27°C) the reading should be
9.3k ± 2k OHMS. If the probe is
within these parameters, reconnect
the J5 plug to the control board.
Spitting or excessive steaming
5. Limit Thermostat (CDBC-APS/
TC/TS/TSR & CEZ-APS/TS/TSR)
6. Tank Heater (CDBC-APS/TC/TS/
TSR & CEZ-APS/TS/TSR)
1. Lime build up on temperature
probe, tank or tank heater
Disconnect the brewer from the
power source. Check for continuity
across the limit thermostat terminals. Continuity should be present.
If not replace the limit thermostat.
(See page 27)
Disconnect the brewer from the
power source. Check for continuity
between the white terminal of the
terminal block and the black wire on
the relay on the control board. There
should be a low OHM reading. If no
continuity is present, check for a
wiring problem, then replace the
tank heater if no wiring problem is
found. (See page 28)
Inspect probe and tank assembly
for excessive lime deposits. Delime
as required.
Page 14
29253 111103
TROUBLESHOOTING (cont.)
HEATING CIRCUIT (cont.)
PROBLEM PROBABLE CAUSE REMEDY
Spitting or excessive steaming
(cont.)
2a. Temperature Probe (CDBC-APS/
TC/TS/TSR)
2b. Temperature Probe (CEZ-APS/
TS/TSR)
A) Remove the probe from the grommet and submerge in a water bath
of approximately 70°F(21°C). Connect an ohmmeter to pins 3 and 4 of
the J3 connector. At 60°F(16°C)
the reading should be 15.3k ± 2k
OHMS, at 70°F(21°C) the reading
should be 11.8k ± 2k OHMS, and at
80°F(27°C) the reading should be
9.3k ± 2k OHMS. If the probe is
within these parameters, reconnect
the J3 plug to the control board.
B) Remove the probe from the grommet and submerge in a water bath
of approximately 70°F(21°C). Connect an ohmmeter to pins 2 and 3 of
the J5 connector. At 60°F(16°C)
the reading should be 15.3k ± 2k
OHMS, at 70°F(21°C) the reading
should be 11.8k ± 2k OHMS, and at
80°F(27°C) the reading should be
9.3k ± 2k OHMS. If the probe is
within these parameters, reconnect
the J5 plug to the control board.
Brewer is making unusual noises
3. Control Board (CDBC & CEZ)
1. Plumbing lines
2. Water supply
3. Lime build up
Set the temperature to 200°F (95°C).
Let tank temperature stabilize. If
temperature in tank is above temperature setting by more than 7°F,
replace the control board.(See
pages 21 & 22)
Plumbing lines should not rest on
the counter top.
The brewer must be connected to a
cold water supply.
Remove the tank lid and clean inside of tank with a deliming agent, if
necessary.
Page 15
29253 111103
TROUBLESHOOTING (cont.)
BREWING CIRCUIT
PROBLEM PROBABLE CAUSE REMEDY
Brew cycle will not start 1. Display flashing (CDBC-APS/TC/
TS/TSR) or ready light flashing
(CEZ-APS/TS/TSR)
2. No water
3. No power or incorrect voltage to
the brewer
4. ON/OFF switch not in the "ON"
position
5. Low water temperature (Brew
lockout is enabled)
6. Water not touching refill probe
inside tank
Brewer has shut down due to
malfunction (See Diagnostic Chart
in manual, Page 19, or under top lid
of brewer).
Water lines and valves to the brewer
must be open.
Check for voltage across the black
and white terminals at the terminal
block.
The indicator lamp must be lit
Allow brewer to heat until ready
lamp is lit, or disable the brew lockout feature. (See page 7 or 8)
Press ON/OFF switch (indicator
must be lit). Brewer will refill until
water touches probe inside tank.
Water must be in contact with refill
probe before brew cycle will start.
7. Switch panel (CDBC-APS/TC/TS/
TSR)
Page 16
Disconnect the brewer from the
power source. Disconnect the ribbon connector from the control
board. Check for continuity between
pins 1 & 2 (An arrow on the connector indicates pin 1). No continuity
should be present. Press the BREW
switch. Continuity should be present
for as long as the switch is held
"ON". If no continuity is present,
replace the switch membrane
decal.(See page 23)
29253 111103
TROUBLESHOOTING (cont.)
BREWING CIRCUIT (cont.)
PROBLEM PROBABLE CAUSE REMEDY
Brew cycle will not start (cont.)
Consistently low beverage level in
the dispenser or beverage overflows
dispenser
8. Control board or dispense valve
(CDBC-APS/TC/TS/TSR & CEZ-
APS/TS/TSR)
1. Brew volume (CDBC-APS/TC/TS/
TSR & CEZ-APS/TS/TSR)
NOTE: All volumes to run with
sprayhead attached.
If the start switch (CEZ-APS/TS/
TSR) or switch panel (CDBC-APS/
TC/TS/TSR) is operating properly,
proceed as follows. Attach a voltmeter to the terminals of the dispense valve solenoid. Connect the
brewer to the power source. Turn
on the brewer and press the BREW
switch. Voltage should be present
at the solenoid terminals. If voltage
is not present, refer to the wiring
diagrams and check the wiring harness. If voltage is present, check for
continuity across the terminals of
the solenoid coil. If continuity is not
present, replace the solenoid valve
(See page 26). If continuity is
present, the valve may be stuck
closed.
Set up brewer according to instructions in section
Adjustments
-Brew
Volumes. (See pages 7 or 8) Using
a stop watch or second hand, time
the length of the brew cycle. Record
this time inside the top lid. If service
is ever needed again, use the time
as reference to determine if time
has changed.
2. Lime build up
3. Dispense Valve
Page 17
Inspect the dispense valve and
sprayhead for excessive lime deposits. Delime as required.
Remove dispense valve and clear
any obstructions. Rebuild or replace valve if necessary. (See page
26)
29253 111103
TROUBLESHOOTING (cont.)
BREWING CIRCUIT (cont.)
PROBLEM PROBABLE CAUSE REMEDY
Dripping from sprayhead
Weak beverage
1. Lime build up
2. Dispense valve
1. Sprayhead
2. Water temperature
Inspect the tank assembly for excessive lime deposits. Delime as
required.
Remove the dispense valve and
clear any obstructions. Rebuild or
replace the valve if necessary.(See
page 26)
A clean stainless steel spray-head
must be used for proper extraction.
Place an empty brew funnel on an
empty server beneath the sprayhead. Initiate brew cycle and check
the water temperature immediately
below the sprayhead with a thermometer. The reading must not be
less than 195°F(91°C). Adjust the
temperature setting to increase the
water temperature. Refer to
Set-up
instructions.
Initial
3. Filter type
4. Coffee grind
5. Funnel loading
BUNN® paper filters must be used
for proper extraction.
A fine drip or grind must be used for
proper extraction.
The BUNN® paper filter must be
centered in the funnel and the bed
of grounds leveled by shaking gently.
Page 18
29253 111103
TROUBLESHOOTING (cont.)
BREWING CIRCUIT (cont.)
PROBLEM PROBABLE CAUSE REMEDY
Dry coffee grounds remain in the
funnel
1. Sprayhead
2. Funnel loading
Make sure sprayhead is present and
holes are clear and unobstructed.
There should be separate streams
of water coming out of each hole in
the sprayhead.
The BUNN® paper filter must be
centered in the funnel and the bed
of grounds leveled by shaking gently.
Page 19
29253 111103
DIAGNOSTICS
Intermittent flashing of the READY indicator (Model CEZ) or the bank of temperature indicators (Model CDBC)
indicates that a fault exists. Count the number of flashes between pauses and use this chart as a guide to
investigating the fault.
FLASHES CAUSE THINGS TO CHECK
1 Dry Plug - In Fault - Water Pressure
Sheath of temperature probe dry for 10 minutes after power-up Temperature probe wiring
Fill valve wiring, function, & strainer
Green wire between tank and circuit board
2 Low Tank Level Fault - Water pressure
Level probe dry for 7 minutes after fill valve is energized Level probe wiring
Temperature probe wiring
Fill valve wiring, function, & strainer
3 Low Water Temperature Fault - Tank heater wiring & function
Sensor in tank is calling for heat for 30 minutes or more Temperature probe wiring
4 Tank Sensor Disagreement - Temperature probe wiring
Level probe detects water, but dry plug-in probe dry Level probe wiring
Green wire between tank and circuit board
5 Temp Sensor Out-of-Range - High Sensor not connected to circuit board
6 Temp Sensor Out-of-Range - Low Sensor wires shorted together or to chassis
Page 20
29253 091603
SERVICE
This section provides procedures for testing and
replacing various major components used in this
brewer should service become necessary. Refer to
Troubleshooting
cause of any problem.
WARNING - Inspection, testing, and repair of electrical equipment should be performed only by qualified
service personnel. The brewer should be unplugged
when servicing, except when electrical tests are required and the test procedure specifically states to
plug-in the brewer.
COMPONENT ACCESS
WARNING - Disconnect the brewer from the power
source before the removal of any panel or the replacement of any component.
All components are accessible by the removal of
the top cover or warmer housing and front access
panel.
for assistance in determining the
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:
The top cover is attached with one #4-40 screw.
The front access panel is attached with four #6-32
screws.
Contents
Control Board - CDBC-APS/TC/TS/TSR ............. 22
Control Board - CEZ-APS/TS/TSR...................... 23
Switch Panel - CDBC-APS/TC/TS/TSR .............. 24
ON/OFF Switch - CEZ-APS/TS/TSR .................... 25
BREW Switch (Start) - CEZ-APS/TS/TSR........... 26
Dispense Valve .................................................. 27
Limit Thermostat ............................................... 28
Tank Heater .......................................................29
Refill Valve ......................................................... 31
Wiring Diagrams............................................... 32
TION
BUNN-O-MATIC CORPORA
S/N
URED BY
S :
NUFACT
MA
BUNN
ING PATENT
IRE HERTZ
SPRINGFIELD, ILLINOIS, U.S.A.
E FOLLOW
OF TH
MODEL
VOLTS A.C. AMP WATTS
NDING
PHASE W
R ONE OR MORE
ED UNDE
COVER
E OR MORE OTHER PATENTS MAY BE PE
ON
FIG. 1 COMPONENT ACCESS
P1913
Page 21
29253 111103
SERVICE (cont.)
CONTROL BOARD - Model CDBC-APS/TC/TS/TSR
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P1914
FIG. 2 CONTROL BOARD
Location:
The Control Board is located inside the top cover
behind the front end cap.
Removal and Replacement:
1. Disconnect the black wire and blue wire from the
relay on the control board.
2. Disconnect the 10-pin connector and the 4-pin
connector from the main wiring harness.
3. Disconnect the 11-pin connector from the control
panel.
4. Remove the four #6 screws and four nylon washers and the two #4-40 screws securing the control
board to the end cap assembly.
5. Install a new control board and secure with the
four #6 screws and nylon washers and the two #440 screws to the end cap assembly.
NOTE: The four nylon washers must be installed
under the heads of the four #6 screws to prevent
a possible shorting of the control board circuits.
6. Connect the 11-pin connector from the control
panel.
7. Connect the 10-pin connector and the 4-pin connector from the main wiring harness.
8. Connect the blue wire and black wire to the relay on
the control board.
9. Refer to
Optional Settings
CDBC-APS/TC/TS/TSR Adjustments and
to program the new control
board.
Test Procedures:
The test procedures for the control board will vary
depending upon the problems experienced by the
brewer. Refer to the Troubleshooting guide beginning
on page 9. The troubleshooting guide is divided into
three sections, Refill Circuit, Heating Circuit, and Brewing Circuit.
Page 22
29253 111103
SERVICE (cont.)
CONTROL BOARD - Model CEZ-APS/TS/TSR
J1
RM1
T
TRM2
J2
J3
J5
J4
J6
J7
CAUTION :
WARMERS AND SURFACES ARE HOT
P1915
FIG. 3 CONTROL BOARD
Location:
The Control Board is located inside the trunk
behind the front access panel.
Test Procedures:
The test procedures for the control board will vary
depending upon the problems experienced by the
brewer. Refer to the Troubleshooting guide beginning
on page 9. The troubleshooting guide is divided into
three sections, Refill Circuit, Heating Circuit, and Brewing Circuit.
Removal and Replacement:
1. Disconnect the black wire and blue wire from the
relay on the control board.
2. Disconnect the 8-pin connector and the 6-pin
connector from the main wiring harness.
3. Disconnect the 2-pin connector from the ready
indicator LED.
4. Remove the four #6-32 screws securing the control board to the component mounting bracket.
5. Remove the four spacers from the control board
and attach them to the new board.
6. Locate J6 connector on control board. If jumper is
across pins 1 & 2, board is set to operate tea
brewer or a brewer that DOES NOT use a water
level probe. If jumper is across pins 2 & 3, board
is set to operate a coffee brewer or a brewer that
uses a water level probe. Look at the bottom side
of the control board. Pin 1 of connector J6 is
marked by a square solder pad and pins 2,3 & 4 are
round.
7. Check the jumper on the brew temperature lockout jack for desired function (enabled or disabled).
8. Check the jumper on the temperature jack for
desired brew temperature. The factory setting
should be 200°F(95°C)
9. Install a new control board and secure with the
four #6-32 screws to the component mounting
bracket.
10. Connect the 2-pin connector from the ready indicator LED.
11. Connect the 8-pin connector and the 6-pin connector from the main wiring harness.
12. Connect the blue wire and black wire to the relay on
the control board.
13. Refer to
tional Settings
CEZ-APS/TS/TSR Adjustments and Op-
to program the new control board.
Page 23
29253 091603
SERVICE (cont.)
SWITCH PANEL - Model CDBC-APS/TC/TS/TSR
.A.
INOIS, U.S
ATTS
Z
S/N
MANUFACTURED BY BUNN-O-MATIC CORPORATION
BUNN
HERT
IRE
SPRINGFIELD, ILL
OWING PATENTS :
A.C. AMP W
MODEL
E W
VOLTS
PHAS
MAY BE PENDING
NTS
ATE
HER P
COVERED UNDER ONE OR MOREOF THE FOLL
ONE OR MORE OT
P1916
FIG. 4 SWITCH PANEL
Location:
The Switch Panel is located in the front of the
hood.
Removal and Replacement:
1. Disconnect the 11-pin connector to the switch
panel from the control board.
2. Remove the four #6 screws, nylon washers and
the two #4-40 screws securing the control board
to the end cap assembly and set aside.
3. Gently pry the switch panel from the end cap
assembly.
4 Remove any adhesive that remains on the end cap.
5. Remove the adhesive backing from the new switch
panel. Insert the ribbon connector through the slot
in the end cap and apply the switch panel to the end
cap.
6. Install the control board to the back side of the end
cap using the four #6 screws, nylon washers and
the two #4-40 screws to the end cap assembly.
NOTE: The four nylon washers must be installed
under the heads of the four #6 screws to prevent
a possible shorting of the control board circuits.
7. Reconnect the 11-pin connector from the switch
panel to the control board making sure every pin
on the control board is inserted into the ribbon
cable plug.
Test Procedures:
The test procedures for the switch panel and the
control board will vary depending upon the problems
experienced by the brewer. Refer to the Troubleshooting guide beginning on page 9. The troubleshooting
guide is divided into three sections, Refill Circuit,
Heating Circuit, and Brewing Circuit.
Page 24
29253 111103
SERVICE (cont.)
ON/OFF SWITCH - Model CEZ-APS/TS/TSR
S/N
MANUFACTURED BY BUNN-O-MATIC CORPORATION
BUNN
SPRINGFIELD, ILLINOIS, U.S.A.
MODEL
VOLTS A.C. AMP WATTS
PHASE WIRE HERTZ
R ONE OR MOREOF THE FOLLOWING PATENTS :
COVERED UNDE
ORE OTHER PATENTS MAY BE PENDING
ONE OR M
WARNING
!
DISCONNECT FROM POWER SOURCE
BEFORE REMOVAL OF ANY PANEL OR
REPLACEMENT OF ANY COMPONENT!
CAUTION :
AND SURFACES ARE HOT
WARMERS
FIG. 5 ON/OFF SWITCH
P1917
6. Check for continuity across the center and lower
terminal with the switch in the "ON" position.
Continuity must not be present when the switch is
in the "OFF" position.
If continuity is present as described, reconnect the
black wire to the center terminal and the remaining
wire to the lower terminal.
If continuity is not present as described, replace the
switch.
Removal and Replacement:
1. Remove the wires from the switch terminals.
2. Remove the hose connected to the faucet. Remove
the nut securing the faucet assembly to the brewer
and remove the faucet.
3. Remove the four nuts securing the end cap to the
brewer and remove the end cap.
4. Remove the switch and replace with new switch.
5. Install the front end cap and faucet assembly.
6. Refer to FIG. 6 when reconnecting the wires.
Location:
The ON/OFF switch is located on the front of the
hood.
Test Procedure:
1. Disconnect the brewer from the power source.
2. Viewing the switch from the back remove the white
wire from the upper terminal and the black wire
from the center terminal.
3. With a voltmeter, check the voltage across the
white wire and the black wire. 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.
4. Disconnect the brewer from the power source.
If voltage is present as described, reconnect the white
wire and proceed to #5.
If voltage is not present as described, refer to the
Wiring Diagrams
and check the brewer wiring har-
ness.
WHI to Terminal
Block (White Insert)
BLK to Terminal
Block (Black Insert)
WHI/RED to Control
Board (J1-8)
P1918
FIG. 6 ON/OFF SWITCH WIRING
5. With the black wire removed, remove the wire
from the lower terminal.
Page 25
29253 091603
SERVICE (cont.)
BREW SWITCH (Start) - Model CEZ-APS/TS/TSR
S/N
MANUFACTURED BY BUNN-O-MATIC CORPORATION
BUNN
SPRINGFIELD, ILLINOIS, U.S.A.
MODEL
VOLTS A.C. AMP WATTS
PHASE WIRE HERTZ
COVERED UNDER ONE OR MOREOF THE FOLLOWING PATENTS :
ONE OR MORE OTHER PATENTS MAY BE PENDING
WARNING
!
DISCONNECT FROM POWER SOURCE
BEFORE REMOVAL OF ANY PANEL OR
REPLACEMENT OF ANY COMPONENT!
WARMERS AND SURFACES ARE HOT
CAUTION :
P1917
If continuity is present as described, reconnect the
white/yellow wire to the top terminal and the white/
orange to the bottom terminal.
If continuity is not present as described, replace the
switch.
Removal and Replacement:
1. Remove the white/yellow wire and white/orange
from the BREW switch.
2. Compress the clips inside the hood and gently
push the switch through the opening.
3. Push new switch into the opening and spread the
clips to hold the BREW switch in the hood.
4. Refer to FIG. 8 when reconnecting the wires.
FIG. 7 BREW SWITCH
Location:
The BREW switch is located in the center front of
the hood.
Test Procedure:
1. Disconnect the brewer from the power source.
2. Disconnect the white/yellow wire from the top
switch terminal and the white/orange from the
bottom switch terminal.
3. 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 terminals when the switch is released.
WHI/YEL from
Control Board J5-1
WHI/ORA from
Control Board J5-6
P1851
FIG. 8 BREW SWITCH WIRING
Page 26
29253 091603
SERVICE (cont.)
DISPENSE VALVE
ION
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P1919
FIG. 9 DISPENSE VALVE
Location:
The dispense valve is located inside the top cover
behind the front end cap.
Test Procedures:
1. Disconnect the brewer from the power source.
2. Check the water level in the tank to confirm that it
is within 1/2" from the top of the tank.
3. Connect the brewer to the power source. If the
brewer has been set for brewer temperature lockout, this feature must be disabled. See Page 8 for
procedure.
4. Check the dispense valve for coil action. Place the
ON/OFF switch in the "ON" position, press and
release the BREW switch. Listen carefully in the
vicinity of the dispense valve for a "clicking" sound
as the coil magnet attracts and repels the plunger.
5. Disconnect the brewer from the power source.
6. Connect the voltmeter lead ends to the dispense
valve coil terminals. Connect the brewer to the
power source. Brewer temperature lockout must
be disabled. Place "ON/OFF" Switch in the "ON"
position. Press and release the brew switch. The
indication must be 120 volts ac for two-wire 120
volt models and three-wire 120/208 volt models.
7. Disconnect the brewer from the power source.
If voltage is present as described, but no coil action is
observed, nor "clicking" heard, dispense valve is defective. Replace valve and test again to verify repair.
If voltage is not present as described, refer to
Diagrams
and check the brewer wiring harness. Also
Wiring
check the control board for proper operation. See
Pages 22 and 23.
Removal and Replacement:
1. Disconnect wires from the dispense valve.
2. Drain enough water from the tank so the dispense
valve is above the water level.
3. Remove water lines from the dispense valve.
4. Remove the two #8-32 nuts securing the dispense
valve to the sprayhead panel.
5. Install a new dispense valve using the two #8-32
nuts.
6. Reconnect water lines to the dispense valve and
secure in place with clamps.
7. Refer to FIG. 10 when reconnecting wires.
WHI/GRN from
Control Board
WHI from Terminal
Block
If the sound is heard as described, there may be a
blockage in the dispense valve or the water line to the
sprayhead. Remove the dispense valve and inspect for
wear, and remove waterborne particles.
If the sound is not heard as described, proceed to #6.
Page 27
P1853
FIG. 10 DISPENSE VALVE WIRING
29253 091603
SERVICE (cont.)
LIMIT THERMOSTAT
A
M
BUNN
L
E
D
O
M
D
N
U
D
E
R
E
V
O
C
O
E
N
O
Removal and Replacement:
1. Remove the black and blue wires from limit thermostat terminals.
2. Carefully slide the limit thermostat out from under
the retaining clip and remove limit thermostat.
3. Carefully slide the new limit thermostat into the
retaining clip.
4. Refer to FIG. 12 when reconnecting the wires.
N
O
I
T
A
R
O
P
R
O
C
.
C
I
A
T
.
S
A
.
M
U
-
,
O
S
-
I
N
O
N
N
I
U
L
B
L
I
Y
,
S
B
T
D
T
L
D
A
E
N
E
I
/
Z
F
W
R
S
T
U
G
R
T
N
:
I
E
C
R
S
H
A
T
P
F
S
N
U
E
N
T
P
A
P
M
A
G
E
N
I
R
I
W
W
O
L
L
O
F
.
C
E
.
H
A
T
S
F
T
O
L
E
G
O
R
N
E
V
I
O
S
D
M
A
N
H
R
E
P
P
O
E
E
B
N
O
Y
A
R
E
M
S
T
N
E
T
A
P
R
E
H
T
O
E
R
O
M
R
BLU from Control
Board
P1920
FIG. 11 LIMIT THERMOSTAT
Location:
The limit thermostat is located inside the front
access panel on the front side of the tank.
Test Procedures:
1. Disconnect the brewer from the power source.
2. Disconnect the blue and black wires from the limit
thermostat.
3. With an ohmmeter, check for continuity across the
limit thermostat terminals.
If continuity is present as described, the limit thermostat is operating properly.
If continuity is not present as described, replace the
limit thermostat.
BLK from Terminal
Block
P1800
FIG. 12 LIMIT THERMOSTAT WIRING
Page 28
29253 091603
SERVICE (cont.)
TANK HEATER
P1855
FIG. 13 TANK HEATER
Location:
The tank heater is located inside the tank and
secured to the tank bottom.
Test Procedures:
1. Disconnect the brewer from the power supply.
2. With a voltmeter, check the voltage across the
white or red wire from the terminal block and the
black wire from the control board. Connect the
brewer to the power source. The indication must
be 120 volts ac for two wire 120 volt models or 240
volts ac for three wire 120/240 volt models.
3. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #4
If voltage is not present as described, refer to the
Wiring Diagrams
and check wiring harness.
4. Disconnect the black wire and the white wire or red
wire from the tank heater terminals.
5. Check for continuity across the tank heater termi-
nals.
If continuity is present as described, reconnect the
wires, the tank heater is operating properly.
If continuity is not present as described, replace the
tank heater.
NOTE- If the tank heater remains unable to heat,
remove and inspect heater for cracks in the sheath.
Removal and Replacement:
1. Remove the top cover or top warmer housing and
front access panel as previously described.
2. Disconnect the vent hose from the top of the tank
by pulling the elbow fitting from the grommet in
the top of the tank lid.
3. Drain water from the tank.
4. Disconnect the water supply tube to the dispense
valve from the side of the tank.
5. Disconnect the water supply tube to the solenoid
valve from the bottom of the tank.
6. On brewers with faucet, disconnect the outlet
water line to the faucet from the side of the tank.
7. Disconnect the temperature probe from the top of
the tank by pulling the probe from the grommet in
the top of the tank lid.
8. Disconnect the pink wire from the level probe.
9. Disconnect the green wire from the top of the tank.
10. Disconnect the limit thermostat from the side of
the tank.
11. Disconnect the two white wires from the tank
warmer blanket.
12. Disconnect the black wire and the white or red wire
from the tank heater terminals.
13. Remove the four #8-32 nuts securing the tank to
the mounting brackets and remove the tank assembly.
14. Remove the eight #8-32 nuts securing the tank lid
to the tank.
15. Remove the two hex nuts securing the tank heater
to the bottom of the tank. Remove tank heater with
gaskets and discard.
16. Install new tank heater with gaskets to the bottom
of the tank and secure with two hex nuts.
Page 29
29253 091603
SERVICE (cont.)
TANK HEATER (Cont.)
17. Install tank assembly onto mounting brackets and
secure in place with four #8-32 nuts.
18. Install tank lid and secure in place with eight #8-32
nuts.
19. Connect the two white wires of the tank warmer
blanket.
20. Connect the limit thermostat to the front of the tank
assembly.
21. Connect the green wire to the tank mounting
bracket using #8-32 nut.
22. Connect the pink wire to the level probe.
23. Insert the temperature probe through the grommet in the tank lid.
24. Install the elbow fitting of the vent hose into the
grommet in the tank lid.
25. On brewers with faucet, connect the outlet water
line of the faucet to the side of the tank and secure
with clamp.
26. Connect the water supply tube from the solenoid
to the bottom of the tank and secure with clamp.
27. Connect the water supply tube from the dispense
valve to the side of the tank and secure with clamp.
28. Refer to FIG. 14 when reconnecting the tank heater
wires.
29. Install access panels and covers and refer to
Set-up
for refill and operation.
Initial
BLK to Control Board
WHI or RED to Terminal
Block
P1856
FIG. 14 TANK HEATER WIRING
Page 30
29253 091603
SERVICE (cont.)
REFILL VALVE
If continuity is not present as described, replace the
refill valve.
J1
M1
TR
2
RM
T
J2
J3
J5
J4
J6
J7
CAUTION :
WARMERS AND SURFACES ARE HOT
P1915
FIG. 15 REFILL VALVE
Location:
The refill valve is located inside the trunk on the
lower center part of the component bracket.
Test Procedures:
1. Disconnect the brewer from the power source.
2. Disconnect the white and white/blue wires from
the refill valve. Set the "ON/OFF" switch in the "ON"
upper position.
3. With a voltmeter, check the voltage across the coil
wires. 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.
4. Disconnect the brewer from the power source.
6. Check the refill valve for coil action. Connect the
brewer to the power source. With "ON/OFF" switch
in the "ON' upper position press start switch and
listen carefully in the vicinity of the refill valve for
a" clicking" sound as the coil magnet attracts.
7. Disconnect the brewer from the power source.
If the sound is heard as described and water will not
pass through the refill valve, there may be a blockage
in the water line before the refill valve or, the solenoid
valve may require inspection for wear, and removal of
waterborne particles.
If the sound is not heard as described, replace the refill
valve.
Removal and Replacement:
1. Remove both wires from the refill valve.
2. Turn off the water supply to the brewer.
3. Disconnect the water lines to and from the refill
valve.
4. Remove the two 1/4"-20 screws securing the refill
valve mounting bracket to the component bracket.
Remove bracket and valve as an assembly.
5. Using two 1/4"-20 screws install the new refill
valve and bracket to the component bracket.
6. Securely fasten the water lines to and from the
valve.
7. Refer to FIG. 16 when reconnecting the wires.
If voltage is present as described, proceed to #5.
If voltage is not present as described, refer to
Diagrams
and check brewer wiring harness.
Wiring
5. Check for continuity across the refill valve coil
terminals.
If continuity is present as described, reconnect the
white and white/blue wires from the circuit board.
Page 31
WHI from Terminal
Block
WHI/BLU from
Control Board
FIG. 16 REFILL VALVE WIRING
P1858
29253 091603
SCHEMATIC WIRING DIAGRAM CDBC-APS/TS/TSR
EARLY MODELS
L2
L1
LIMIT
BLK-14
BLK
J1-1
C
J1-2
O
N
T
R
O
L
P
C
B
O
A
R
D
COM
N.O.
J1-1
J1-5
J1-10
J2-1
THERMOSTAT
WHI
COUNTER
(OPTIONAL)
BLK
BLK
BLU-14
BLK-14
WHI
BLK
WHI/BLU
WHI/GRN
CONTROL PANEL ASSY
BREW SW
BLU-14
"KEEP WARM" HEATER
BLK-14
BLK
WHI/GRN
DISPENSE
SOL
GRN
TANK HEATER
GRN
WHI-14 (MODELS 15 & 20)
RED-14 (MODEL 35)
REFILL
WHI/BLU
SOL
N
WHI
WHI
WHI
WHI
WHI
J2-6
J2-11
J3-1
J3-4
PNK
GRN
WHI
BLK
ON/OFF SW
HIDDEN SW
STATIC
SHIELD
120V AC 2 WIRE
120/208V AC 3 WIRE
120/240V AC 3 WIRE
LEVEL
PROBE
29257.0000B 12/99 ©1998 BUNN-O-MATIC CORPORATION
t°
SINGLE PHASE
Page 32
29253 111103
SCHEMATIC WIRING DIAGRAM CEZ-APS/TS/TSR
GRN
AUXILIARY
LEVEL
PROBE
OUTLET
"KEEP WARM" HEATER
WHI
WHI/RED
WHI/ORA
GRN
BLK-14
WHI/BLU
TANK HEATER
WHI
REFILL
SOL
WHI/GRN
WHI
WHI-14 (MODELS 15 & 20)
RED-14 (MODEL 35)
DISPENSE
SOL
120V AC 2 WIRE
120/208V AC 3 WIRE
120/240V AC 3 WIRE
SINGLE PHASE
WHI
WHI
WHI
WHI
L2
N
L1
BLK
LIMIT
THERMOSTAT
COUNTER (OPTIONAL)
BLK
BLK
BLU-14
BLK-14
WHI
WHI/BLU
WHI/GRN
BLK
WHI/RED
WHI/YEL
BLK
WHI
GRN
PNK
WHI/ORA
GRY
PNK
BLU-14
ON/OFF SWITCH
BLK
BLK
BREW SWITCH
C
O
N
T
R
O
L
B
O
A
R
D
BLK
TRM-1
TRM-2
J1-1
J1-8
J5-1
J5-6
J7-1
J7-2
BLK-14
COM
N.O.
t°
29341.0000B 6/99 ©1998 BUNN-O-MATIC CORPORATION
Page 33
29253 091603
SCHEMATIC WIRING DIAGRAM
CDBC 15, 20 & 35 APS/TC/TS
LATE MODELS
N
L1
LIMIT
BLK-14
BLK
J1-1
C
J1-2
O
N
T
R
O
L
P
C
B
O
A
R
D
COM
N.O.
J1-1
J1-5
J1-10
J2-1
THERMOSTAT
WHI
COUNTER
(OPTIONAL)
BLK
BLK
BLU-14
BLK-14
WHI
BLK
WHI/BLU
WHI/GRN
CONTROL PANEL ASSY
BREW SW
BLU-14
"KEEP WARM" HEATER
BLK-14
WHI/GRN
DISPENSE
SOL
GRN
TANK HEATER
WHI-14 (MODELS 15 & 20)
RED-14 (MODEL 35)
REFILL
WHI/BLU
SOL
WHI
WHI
WHI
WHI
L2
J2-6
J2-11
J3-1
J3-4
J5-1
PNK
GRN
WHI
BLK
BLK
ON/OFF SW
HIDDEN SW
STATIC
SHIELD
120V AC 2 WIRE
120/208V AC 3 WIRE
120/240V AC 3 WIRE
SINGLE PHASE
LEVEL
PROBE
t°
29257.0001D 02/04 ©1999 BUNN-O-MATIC CORPORATION
Page 34
29253 021604
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