BUNN
®
H10X
WARNING
!
Very Hot Water
Use With Care!
OPERATING & SERVICE MANUAL
BUNN-O-MATIC CORPORATION
POST OFFICE BOX 3227
SPRINGFIELD, ILLINOIS 62708-3227
PHONE: (217) 529-6601 FAX: (217) 529-6644
10889.0000C 7/00 ©1995 Bunn-O-Matic Corporation
WARRANTY
Bunn-O-Matic Corp. (“Bunn”) warrants the equipment manufactured by it to be commercially free from defects
in material and workmanship existing at the time of manufacture and appearing within one year from the date of
installation. In addition:
1.) Bunn warrants electronic circuit and/or control boards to be commercially free from defects in material and
workmanship for two years from the date of installation.
2.) Bunn warrants the compressor on refrigeration equipment to be commercially free from defects in material
and workmanship for two years from the date of installation.
3.) Bunn warrants that the grinding burrs on coffee grinding equipment will grind coffee to meet original factory
screen sieve analysis for three years from date of installation or for 30,000 pounds of coffee, whichever comes first.
This warranty does not apply to any equipment, component or part that was not manufactured by Bunn or that,
in Bunn’s judgement, has been affected by misuse, neglect, alteration, improper installation or operation, improper
maintenance or repair, damage or casualty.
THE FOREGOING WARRANTY IS EXCLUSIVE AND IS IN LIEU OF ANY OTHER WARRANTY, WRITTEN OR
ORAL, EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF EITHER
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. The agents, dealers or employees of Bunn are
not authorized to make modifications to this warranty or to make additional warranties that are binding on Bunn.
Accordingly, statements by such individuals, whether oral or written, do not constitute warranties and should not
be relied upon.
The Buyer shall give Bunn prompt notice of any claim to be made under this warranty by telephone at (217)
529-6601 or by writing to Post Office Box 3227, Springfield, Illinois, 62708-3227. If requested by Bunn, the Buyer
shall ship the defective equipment prepaid to an authorized Bunn service location. If Bunn determines, in its sole
discretion, that the equipment does not conform to the warranty, Bunn shall repair the equipment with no charge
for parts during the 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.
THE BUYER’S REMEDY AGAINST BUNN FOR THE BREACH OF ANY OBLIGATION ARISING OUT OF THE SALE
OF THIS EQUIPMENT, WHETHER DERIVED FROM WARRANTY OR OTHERWISE, SHALL BE LIMITED, AS
SPECIFIED HEREIN, TO REPAIR OR, AT BUNN’S SOLE OPTION, REPLACEMENT OR REFUND.
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.
2
10889 091599
USER NOTICES
Carefully read and follow all notices on the equipment and in this manual. They were written for your protec-
tion. All notices are to be kept in good condition. Replace any unreadable or damaged labels.
00656.0000
#00831.0000
12593.0000
10044.0000
NOTICE
ALL COMPONENTS ARE
200 TO 240 VOLT A.C.
Replace only with
components listed in the
accompaning literature
rated for the same
voltage
12537.0000
3
10889 072700
ELECTRICAL REQUIREMENTS
CAUTION - The dispenser must be disconnected from the power source until specified in
Initial Set-Up.
This dispenser requires 2-wire, grounded service rated 208 or 240 volts ac, 40 amp, single phase.
Refer to the dispenser’s dataplate for exact voltage requirement.)
(
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.
L2 RED
3. Remove the side panel.
4. Install the proper electrical wiring to the terminal block.
5. Connect the dispenser to the power source and verify the voltage at the termi-
L1 BLACK
nal block before proceeding. Reinstall the side panel.
6. If plumbing is to be hooked-up later be sure the dispenser is disconnected
from the power source. If Plumbing has been hooked-up, the dispenser is
ready for
Initial Set-Up
.
PLUMBING REQUIREMENTS
208 or 240V.A.C.
This dispenser must be connected to a COLD WATER system with operating pressure between 20 and 90 psi
(138 and 620 kPa) from a 1⁄2" or larger supply line. A shut-off valve should be installed in the line before the
dispenser. 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 1⁄4" flare.
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. At least 18 inches of an FDA approved flexible beverage tubing, such as
reinforced braided polyethylene or silicone, before the dispenser will facilitate movement to clean the countertop.
It can be purchased direct from Bunn-O-Matic (P.N. 00326-0000). Bunn-O-Matic does not recommend the use
of a saddle valve to install the dispenser. 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 and securely attach it to the flare fitting at the rear of the dispenser.
2. Turn on the water supply.
4
10889 072700
INITIAL SET-UP
CAUTION - The dispenser must be disconnected from the power source throughout the initial set-up, except
when specified in the instructions.
1. Connect the dispenser to the power source and turn on the water supply.
2. The “HEATER” LED will glow for approximately five seconds. During this time, the electronic circuitry will
check for a full tank of water.
3. If the tank is not full of water, the refill circuit will energize, indicated by the “REFILL” LED glowing. Water
will automatically flow into the tank to the proper level and then shut off.
4. When the tank is full of water, the heater circuit will energize, indicated by the “HEATER” LED glowing
intermittently until the proper temperature is achieved. A completely cold tank will take approximately
twenty minutes for the water to heat.
5. The “READY” LED will glow when the proper water temperature is achieved.
NOTE - Stop dispensing if the “READY” LED is off. Dispense only when the ”READY” LED glows.
DRAINING THE DISPENSER
CAUTION - The dispenser must be disconnected from the power source throughout these steps.
1. Disconnect the dispenser from the power source.
2. Shut-off and disconnect the incoming water supply
3. Remove the small screws from the sides and front of the top panel.
4. Gently remove one of the grommets from the tank lid.
5. Insert a tube to the bottom of the tank and syphon ALL of the water out.
NOTE - The dispenser must be refilled using the INITIAL SET-UP steps before reconnecting to the power source.
CLEANING
The use of a damp cloth rinsed in any mild, non-abrasive, liquid detergent is recommended for cleaning all
surfaces on Bunn-O-Matic equipment.
5
10889 091599
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 person-
nel.
• All electronic components have 200-240 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 dispenser is heated at all times. Keep away from combustibles.
WARNING
• Exercise extreme caution when servicing electrical equipment.
• Disconnect the dispenser from the power source when servicing, except when electrical tests are speci-
fied.
• Follow recommended service procedures.
• Replace all protective shields or safety notices.
PROBLEM
Equipment will not operate.
PROBABLE CAUSE
1. No power or incorrect voltage
REMEDY
(A) Check the terminal block for the
correct voltage. It should be 200 to
240 volts ac across the red and black
terminals for 200 to 240 volt models.
(B) Check circuit breakers or fuses.
2. Overflow protection switch
Refer to
tion switch for testing procedures.
Service -
Overflow protec-
See page 16.
6
10889 091599
TROUBLESHOOTING (cont.)
PROBLEM
Automatic refill will not operate af-
ter drawing hot water.
PROBABLE CAUSE
1. No water
2. Water strainer/flow control
3. Overflow protection switch
4. Liquid level system
5. Solenoid valve
REMEDY
Check plumbing and shut-off valves.
(A) Direction of flow arrow must be
pointing towards dispenser.
(B) Remove the strainer/flow control and check for obstructions. Clear
or replace.
Refer to
Service -
Overflow protection switch for testing procedures.
See page 16.
Refer to
Service -
Electronic controls
for testing procedures. See page 11.
Refer to
Service -
Solenoid valve for
testing procedures. See page 17.
Refer to
Service -
Solenoid valve for
testing procedures. See page 17.
Water flows into the tank continuously. (Dispenser disconnected from
1. Solenoid valve
Refer to
Service -
Electronic controls
for testing procedures. See page 11.
power source).
Water flows into the tank continuously (Dispenser connected to
1. Liquid level system
Refer to
tion switch for testing procedures.
See page 16.
Service -
Overflow protec-
power source).
Water is cold.
1. Overflow protection switch
Refer to
for testing procedures. See page 15.
Service -
Limit thermostat
2. Limit thermostat
CAUTION - Do not eliminate or bypass limit thermostat. Use only B.O.M. replacement part #23717.0001.
7
10889 091599
TROUBLESHOOTING (cont.)
PROBLEM
Water is cold (cont.)
Water boils continuously.
PROBABLE CAUSE
3. Tank heater
4. Temperature control
5. Dry plug protection
1. Temperature control
2. Lime build-up
REMEDY
Refer to
Service -
Tank heater for
testing procedures. See page 19.
Refer to
Service -
Electronic controls
for testing procedures. See page 12.
Check connections to Interlock
board and sheath of tank temperature probe.
Refer to
Service -
Electronic controls
for testing procedures. See page 12.
Inspect the tank assembly for excess
lime deposits. Delime as required.
CAUTION - Tanks and tank components should be delimed regularly depending on local water conditions. Excessive mineral build-up on stainless steel surfaces can initiate corrosive reactions resulting in serious leaks.
Dispenser is making unusual noises.
1. Solenoid valve
The nut on top of the solenoid valve
must be tight or it will vibrate during operation.
2. Plumbing lines
Plumbing lines should not be resting on the counter top.
3. Water supply
(A) the dispenser must be connected
to a cold water line.
(B) Water pressure to the dispenser
must not be higher than 90 psi. Install a regulator if necessary to lower
the working pressure to approxi-
mately 50 psi.
Ready indicator will not light. (when
temperature is within 4˚ of its selected setting.)
1. Temperature control
Refer to
Service -
Electronic controls
for testing procedures. See page 12.
2. Ready Indicator LED
8
Replace the indicator LED.
10889 072700
SERVICE
This section provides procedures for testing and
replacing various major components used in this dispenser should service become necessary. Refer to
Troubleshooting for assistance in determining the cause
of any problem.
Component Access
WARNING - Disconnect the dispenser from the power
source before the removal of any panel or the replacement of any component.
WARNING
!
Very Hot Water
Use With Care!
P878
WARNING
!
Very Hot Water
Use With Care!
P878
The check valve, electronic control assembly,
overflow protection switch, solenoid valve, overflow
tube temperature sensor, triac assembly and terminal
block are located on the side of the dispenser. Access
is gained by removing the side panel. The panel is attached with eight 8-32 slotted-head screws.
The limit thermostat, liquid level probe, tank
heater, and temperature sensor are located at the top
of the dispenser. Access is gained by removing the top
lid, attached with four 4-40 slotted-head screws.
WARNING - Inspection, testing, and repair of electrical equipment should be performed only by qualified
service personnel. Disconnect the dispenser fromthe
power source when servicing, except when electrical
tests are required and the test procedure specifically
states to connect the dispenser to the power source.
Electronic Controls ..................................... 10-14
Limit Thermostat ............................................. 15
Safety Overflow Switch .................................... 16
Solenoid Valve ................................................. 17
Tank Heater ...................................................... 19
Electrical Schematic......................................... 20
9
10889 091599
SERVICE (cont.)
Electronic Control Assembly Troubleshooting:
Check these items first
• Is circuit board popped out of bracket?
• Is circuit board wet due to misaligned overflow
tube?
• Is water in overflow cup activating float switch?
• Is overflow cup not making good contact with tank?
• Is dispenser being operated with panels removed?
H10X LIQUID LEVEL CONTROL
PROBLEM: Does Not Refill
Overflow Cup Full
Disconnect Level Probe
Voltage present at
Solenoid Valve
?
Unplug P2 from Circuit Board
Yes
?
No
Yes
No
Remove Power
Drain cup
Retry
Does Water Flow
?
No
Replace Solenoid Valve
Yes
Replace Probe
Triac Assy
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P1991
FIG. 1 ELECTRONIC CONTROL AND TRIAC
Location:
The electronic control assembly is located inside
the side of the dispenser. Access will also be needed
to the temperature sensor, overflow tube temperature
sensor, and liquid level probe located on the tank lid
and to the triac assembly located on the inside of the
rear wall.
General:
This system controls the liquid level and water temperature of the dispenser. These two functions act independently of each other and should be tested separately.
Voltage present at
Solenoid Valve
?
Yes
Repair shorted wires
leading to P2.
No
Replace Control Assembly
H10X LIQUID LEVEL CONTROL
PROBLEM: Overflows
Drain cup
Unplug P2 from Circuit Board
Retry
Overflow
?
Ye s
Drain cup
Disconnect wire from
Refill Probe
Short Probe Wire
To Chassis
Retry
Overflow
?
Ye s
Drain cup
Disconnect Wire From
Solenoid Valve
Retry
Overflow
?
No
Replace Control Assembly
No
No
Ye s
Repair shorted wires
leading to P2
Replace Probe
Replace Solenoid Valve
10
10889 091599
SERVICE (cont.)
Electronic Controls (cont.)
Liquid Level Control Test Procedure
1. Disconnect the dispenser from the power source.
2. Check the voltage across terminals 3 & 4 of the
electronic control assembly with a voltmeter. Connect the dispenser to the power source. The indication must be 200 to 240 volts ac for 200 to 240
volt models.
3. Disconnect the dispenser from the power source.
If voltage was present as described, proceed to #4.
If voltage was not present as described, refer to
the Wiring Diagrams and check the dispenser wiring harness.
4. Remove the pink wire from terminal 5 of the electronic control assembly.
5. Check the voltage across terminals 1 & 4 of the
electronic control assembly with a voltmeter. Connect the dispenser to the power source. The indication must be 200 to 240 volts ac for 200 to 240
volt models after a delay of approximately 5 seconds.
6. Disconnect the dispenser from the power source.
9. Check the voltage across the terminals 1 & 4 of the
electronic control assembly with a voltmeter. Connect the dispenser to the power source. The indication must be 200 to 240 volts ac for 200 to 240
volt models after a delay of approximately 5 seconds.
10. Touch the screw head end of the probe to the dispenser housing. The indication must be 0.
11. Move the probe away from the dispenser housing.
The indication must again be 200 to 240 volts ac
for 200 to 240 volt models after a delay of approximately 5 seconds.
12. Disconnect the dispenser from the power source.
If voltage was present as described, reinstall the probe,
the sensing function of the system is operating properly.
If voltage was not present as described, check the pink
probe wire and the green ground wire for continuity
and/or replace the probe.
Temperature control Flow Charts
H10X THERMOSTAT
PROBLEM: Water Not Hot Enough
If voltage was present as described, the liquid level
control of the system is operating properly, proceed to
#7.
If voltage was not present as described, replace the
electronic control assembly and the temperature sensor in the tank lid.
NOTE - Each electronic control assembly is calibrated
to a temperature sensor. Both components MUST be
replaced as a set.
7. Reconnect the pink wire to terminal 5 of the electronic control assembly.
8. Loosen the compression fitting, remove the probe
from the tank lid, and inspect it for mineral deposits. Replace it if necessary. Keep the exposed ends
of the probe away from any metal surface of the
dispenser.
Jumper JP1
In Boil Position
?
Ye s
Heater Light On
Constantly
?
Ye s
Measure Voltage
At Tank Heater
Voltage Present
?
No
Limit Thermostat OK
?
Ye s
Replace Control Assembly
Measure Voltage
At Tank Heater
Voltage Present
?
Ye s
Recheck Water Temperature
No
Reposition Jumper
No
Replace Steam Sensor
Ye s
Replace Tank Heater
No
Replace Limit Thermostat
No
Check For Split Tank Heater
Reinstall Original
Control Assembly
Replace Triac
Heater Light On
Constantly
?
No
Replace Control Assembly
Ye s
Recheck Water Temperature
11
10889 091599
SERVICE (cont.)
Electronic Controls (cont.)
Temperature Control Flow Charts (cont.)
H10X THERMOSTAT
PROBLEM: Boils Excessively - Fills Cup
Drain cup
Retry
Heater Light On While
Boiling
?
Disconnect Blue Wire From
Control Board Pin 7
Retry
Still Boiling
?
No
Replace Control Assembly
Ye s
Replace Steam Sensor
No
Ye s
Ye s
Still Boiling
?
No
Finished
Replace Triac Assembly
Check For Split
Tank Heater
Replace Control Assembly
If the indicator was on or blinking, the temperature
sensor is operating properly, proceed to #7.
If the indicator was off, check the sensor connection
on the electronic control circuit board and/or replace
the temperature sensor and the electronic control assembly.
NOTE - Each temperature sensor is calibrated to an
electronic control assembly. Both components MUST
be replaced as a set.
7. Check the voltage across the tank heater terminals
with a voltmeter. Connect the dispenser to the
power source. The indication must be 200 to 240
volts ac for 200 to 240 volt models while the red
indicator on the circuit board is on or blinking.
8. Disconnect the dispenser from the power source.
If voltage was present as described, the temperature
control of the system is operating properly.
If voltage was not present as described, contact BunnO-Matic to order an electronic control assembly temperature sensor, and triac assembly for evaluation and
proceed to #9.
Temperature Control Test Procedure
1. Disconnect the dispenser from the power source.
2. Check the voltage across terminals 3 & 4 of the
electronic control circuit board with a voltmeter.
Connect the dispenser to the power source. The
indication must be 200 to 240 volts ac for 200 to
240 volt models.
3. Disconnect the dispenser from the power source.
If voltage was present as described, proceed to #4.
If voltage was not present as described, refer to the
Wiring Diagram and check the dispenser wiring harness.
4. Connect the dispenser to the power source .
5. Observe the red indicator on the electronic control
circuit board.
6. Disconnect the dispenser from the power source.
9. Replace the electronic control assembly and temperature sensor.
NOTE - Each electronic control assembly is calibrated
to a temperature sensor. Both components MUST be
replaced as a set.
10. Check the voltage across the tank heater terminals
with a voltmeter. Connect the dispenser to the
power source. The indication must be 200 to 240
volts ac for 200 to 240 volt models while the red
indicator on the circuit board is on or blinking.
12
10889 091599
SERVICE (cont.)
Electronic Controls (cont.)
11. Disconnect the dispenser from the power source.
If voltage was present as described, return the new
triac assembly to Bunn-O-Matic for credit. The temperature control of the system is operating properly. If
voltage was not present as described, reinstall your
existing electronic control assembly and temperature
sensor, and proceed to #12
12. Replace the triac assembly.
13. Check the voltage across the tank heater terminals
with a voltmeter. Connect the dispenser to the
power source. The indication must be 200 to 240
volts ac for 200 to 240 volt models while the red
indicator on the circuit board is on or blinking.
14. Disconnect the dispenser from the power source.
If voltage was present as described, the temperature
control of the system is operating properly. Return the
new electronic control assembly and temperature sensor to Bunn-O-matic for credit.
5. Install the new temperature sensor into the grommet on the tank lid. Route the wires to the location
of the new electronic control assembly.
6. Attach the temperature sensor, overflow tube temperature sensor, and indicator wires to the electronic control assembly.
7. Fasten the new electronic control assembly to its
bracket.
8. Reconnect the wires.
9. Review the initial set-up procedures.
BLU to Triac Assy
TAN to Triac Assy
BLU to Triac Assy
TAN to Triac Assy
PNK to Liquid Level Probe
RED to Terminal block
RED to Solenoid
BLK to Overflow Safety Switch
GRN to Chassis Ground
WHI/BLU to Solenoid
Electronic Control Removal and Replacement
NOTE - Each electronic control assembly is calibrated
to a temperature sensor probe. Both components
MUST be replaced as a set.
1. Remove all wires from the electronic control assembly terminals.
2. Remove the two 8-32 screws holding the electronic
control assembly to the component bracket.
3. Disconnect the temperature sensor, overflow tube
temperature sensor, and indicator wires from the
left side of the electronic control assembly board.
4. Remove the temperature sensor from the grommet in the tank lid.
FIG. 2 WIRING CONNECTIONS
WHI & WHI to
Temperature Sensor
PNK & GRY to
Heater Indicator
Refill Indicator
Power Indicator
Ready Indicator
GRY & GRY
to Thermistor
FIG. 3 WIRING CONNECTIONS
P1992
P1
P2
P101
P1992
13
10889 091599
SERVICE (cont.)
Electronic Controls (cont.)
Triac Assembly Removal and Replacement
NOTE - Each triac installation requires the use of an
approved silicone heat sink compound. Bunn-O-Matic
recommends the use of Dow Corning 340 compound
or equivalent. It can be purchased direct from Bunn-OMatic (P.N. M2522.1000)
1. Remove the existing triac assembly held in place
with a 10-32 hex keps nut.
2. Apply a small amount of the silicone heat sink compound to the copper heat sink.
3. Securely fasten the new triac assembly to the rear
panel in the same relative position as the one removed. Bunn-O-matic recommends tightening the
nut to a torque setting of approximately 18 inchpounds.
4. Disconnect the other ends of the old triac assembly wires.
5. Connect the TAN and BLU wires with spade terminals of the new assembly to the electronic control
assembly, FIG. 2.
6. Connect the BLU wire with the ring terminal to the
tank heater, FIG. 12.
7. Connect the WHI/VIO wire of the new assembly to
the RED terminal at the terminal block.
14
10889 091599
SERVICE (cont.)
Limit Thermostat
Limit Thermostat
Location:
The limit thermostats are located on the tank lid. To
test the limit thermostats, access will also be needed
to the terminal block located on the side of the dispenser.
P1993
FIG. 5 LIMIT THERMOSTAT
Test Procedure:
1. Disconnect the dispenser from the power source.
2. There are two black wires on the limit thermostat
terminals. One comes from the terminal block. The
other goes directly to the tank heater terminal. Remove the black wire at the limit thermostat coming
from the terminal block.
3. Check the voltage across the black wire removed
from the limit thermostat and the red wire of the
terminal block with a voltmeter. Connect the dispenser to the power source. The indication must
be 200 to 240 volts ac for 200 to 240 volt models.
4. Disconnect the dispenser from the power source.
If voltage was present as described, reconnect the black
wire and proceed to #5.
If voltage was not present as described, refer to the
Wiring Diagrams and check the dispenser wiring harness.
5. Check for continuity across the terminals of the
limit thermostat.
If continuity is not present as described, the circuit is
broken. Press the reset button of the limit thermostat
and recheck for continuity.
If continuity is not present as described, replace the
limit thermostat.
Removal and Replacement:
1. Remove both wires from the limit thermostat terminals.
2. Remove the two #10-32 nuts attaching the limit
thermostat to the top of the tank.
3. Install the new limit thermostat and secure into
place with two #10-32 nuts.
4. Refer to FIG. 6 when reconnecting the wires.
BLK to Terminal Block
Reset
BLK to Tank Heater
P1776
15
FIG. 6 LIMIT THERMOSTAT WIRING
10889 091599
SERVICE (cont.)
Overflow Protection Switch
P1993
FIG. 7 OVERFLOW PROTECTION SWITCH
Location:
The overflow protection switch is located within the
side of the dispenser inside the copper overflow cup.
For testing or removal of the overflow protection switch,
access may also be needed by removing the two screws
attaching the electronic control assembly to its mounting bracket.
Removal and Replacement:
1. Disconnect the black wires from the overflow protection switch.
2. Remove the nut beneath the copper overflow cup.
3. Remove the entire switch assembly from the cup.
4. Place the new switch assembly into the cup, wires
first. Make sure that a gasket is in place around the
threaded switch stem.
NOTE - The magnets must be at the top of the float and
there must be NO stainless steel washers installed for
the overflow protection switch to operate properly.
5. Install the nut beneath the copper overflow cup.
Be sure not to overtighten.
6. Reconnect the wires, FIG. 8.
Test Procedure:
1. Once voltage is verified at the power source, check
for continuity across the overflow protection switch
red wires only until the plastic float is raised and
check that continuity returns when the plastic float
is again lowered.
If continuity is present as described, reconnect each
of the red wires to the black wires, the overflow protection switch is operating properly.
If continuity is not present as described, replace the
overflow protection switch.
RED to BLK Wire from
Terminal Block
RED to BLK Wire from
Electronic Control #3
P1777
FIG. 8 OVERFLOW PROTECTION WIRING
16
10889 091599
SERVICE (cont.)
Solenoid Valve
Location:
The solenoid valve is located within the side of the dispenser on the right side near the bottom.
To test the solenoid valve, access will also be needed
to the electronic control assembly.
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IN
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HAZARDOUS
VOLTAGE
DISCONNECT FROM
POWER SOURCE
BEFORE REMOVING!
.750 gpm FLOW
90 psig max operating pressure
BUNN
Strainer/Flow Control # 22300.0750
(Repl. Screen #23721.0000)
(Repl. Flow Washer #20526.0750)
If voltage was present as described, proceed to #5.
If voltage was not present as described, refer to the
Wiring Diagrams and check the dispenser wiring harness.
5. Remove both wires from the solenoid valve coil
terminals.
6. Check for continuity across the solenoid valve coil
terminals.
If continuity is present as described, reconnect the
wires and proceed to #7.
If continuity is not present as described, replace the
solenoid valve coil.
7. Check the solenoid valve for coil action. Connect
the dispenser to the power source. Listen carefully
in the vicinity of the solenoid valve for a “clicking”
sound after approximately 5 seconds, as the coil
magnet attracts the plunger.
8. Disconnect the dispenser from the power source.
9. Reconnect the pink wire to terminal 5 of the electronic control assembly.
P1994
FIG. 9 SOLENOID VALVE
Test Procedure:
1. Disconnect the dispenser from the power source
and turn off the water supply to the dispenser.
2. Remove the pink wire from terminal 5 of the electronic control assembly.
3. Check the voltage across the solenoid valve coil
terminals with a voltmeter. Connect the dispenser
to the power source. The indication must be 200
to 240 volts ac for 200 to 240 volt models after a
delay of approximately 5 seconds.
4. Disconnect the dispenser from the power source.
If the sound was heard as described and water will not
pass through the solenoid valve, there may be a blockage in the water line before or after the solenoid valve
or the solenoid valve may require inspection for wear
and removal of waterborne particles.
If the sound was not heard as described, replace the
solenoid valve.
Removal and Replacement:
1. Remove all wires from the solenoid valve coil.
2. Turn off the water supply to the dispenser.
3. Disconnect the water lines to and from the solenoid valve.
4. Remove the two 8-32 slotted-head screws holding
the solenoid valve and mounting bracket to the
component bracket.
17
10889 091599
SERVICE (cont.)
Solenoid Valve (cont.)
5. Lift out the solenoid valve.
6. Remove the two 10-32 slotted-head screws holding the solenoid valve to its mounting bracket.
7. Securely install the new solenoid valve to its mounting bracket. The direction of flow arrow must be
pointing towards the tank lid.
8. Attach the solenoid valve and mounting bracket to
the component bracket.
9. Securely fasten the water lines to and from the
solenoid valve.
10. Reconnect the wires, FIG. 10.
WHI/BLU to Electronic
Contol #1
RED to Terminal Block
RED to Electronic Control #5
P1779
FIG. 10 SOLENOID VALVE WIRING
18
10889 091599
SERVICE (cont.)
Tank Heater
Location:
The tank heater is located in the tank lid.
FIG. 11 TANK HEATER
P1993
If voltage is present as described, proceed to #4.
If voltage is not present as described, replace the tank
heater.
4. Remove the tank heater from the tank lid and inspect it for cracks in the sheath.
If continuity is present as described, reinstall the tank
heater. The tank heater is operating properly.
If continuity is not present as described, replace the
tank heater.
Removal and Replacement:
1. Remove the wires to the tank heater.
2. Remove the 8-32 nuts from the tank heater flange.
3. Remove the tank heater.
4. Inspect the tank heater gasket and replace if necessary.
5. Securely install the new tank heater. Be certain of a
watertight seal.
6. Reconnect the wires, FIG. 12.
Test Procedure:
1. Disconnect the dispenser from the power source.
2. Check the voltage across the terminals of the tank
heater with a voltmeter. Connect the dispenser to
the power source. The indication must be 200 to
240 volts ac for 200 to 240 volt models.
3. Disconnect the dispenser from the power source.
BLU to Triac Assy
FIG. 12 TANK HEATER WIRING
BLK to Limit Thermostat
P1780
19
10889 091599
WIRING DIAGRAM
20
10889 091599
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