Bunn H5M Instruction and safety manual

H5M
10267.0000D 7/00 © 1988 BUNN-O-MATIC CORPORATION
BUNN-O-MATIC CORPORATION
POST OFFICE BOX 3227
SPRINGFIELD, ILLINOIS 62708-3227
PHONE: [phone] FAX: [phone]
BUNN
®
OPERATING & SERVICE MANUAL
WARNING
Very Hot Water
Use With Care!
!
DISCONNECT FROM POWER SOURCE
BEFORE REMOVAL OF ANY PANEL OR
REPLACEMENT OF ANY COMPONENT!
WARNING

2
CONTENTS
Introduction ................................................. 2
Warranty ...................................................... 2
User Notices ................................................ 3
Electrical Requirements ............................... 4
Plumbing Requirements .............................. 4
Initial Set-Up................................................ 5
Draining the Dispenser ................................ 5
Cleaning....................................................... 5
Troubleshooting .......................................... 6
Service......................................................... 9
Wiring Schematics..................................... 19
INTRODUCTION
This equipment heats and dispenses water on demand for beverages and cooking purposes. This equipment
is for indoor use, either wall-mounted or on a sturdy counter or shelf.
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.
10267 071900

3
12593.0000
00831.0000
10044.0000
USER NOTICES
The notices on this dispenser should be kept in good condition. Replace unreadable or damaged labels.
00656.0000
10267 071900

4
ELECTRICAL REQUIREMENTS
CAUTION - The dispenser must be disconnected from the power source until specified in Initial Set-Up.
The H5M dispenser requires 2-wire, grounded service rated 120, 208, or 240 volts ac, 20 amp, single phase.
The H5MA, 230V-CE dispenser requires 2-wire, grounded service rated 230 volts ac, 40 amp, single phase, 50/
60Hz
. (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.
3. Remove the upper and lower rear panels. Turn the knob of the thermostat to
the “OFF”position (fully counterclockwise).
4. Install a strain relief and the proper electrical wiring to the terminal block.
5. Connect the dispenser to the power source and verify the voltage at the termi-
nal block before proceeding. Reinstall both rear panels.
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
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 (part number 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.
208 or 240V.A.C.
L2 RED
L1 BLACK
120V.A.C.
NEUTRAL
WHITE
L1 BLACK
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).
P1770
Plumbing Hook-Up
1. Flush the water line and securely attach it to the flare fitting on
the rear of the dispenser.
2. Turn-on the water supply.
CON
NECT FROM
P
OWER SOURCE
BEFORE REMOVING!
O
N
OFF
Fill
water tank before turning -on
thermostat or connecting appliance
to power source.
Do not use near combustibles.
Follow national/local electrical codes.
Electrically ground the chassis.
Use only on a properly protected
circuit capable of the rated load.
FAILURE TO COMPLY RISKS EQUIPMENT
DAMAGE, FIRE, OR SHOCK HAZARD
READ THE ENTIRE OPERATINGMANUAL
INCLUDING THELIMIT OF WARRANTY AND
LIABILITY BEFORE BUYINGORUSINGTHIS PRODUCT
THIS APPLIANCE IS HEATED WHENEVER
CONNECTED TO A POWER SOURCE
00831.0000A 5/88 © 1988 BUNN-O-MATIC CORPORATION
W
ARNING
!
This equipment is to be in
st l
comply with the Basic Pl
m
the Building O
ffici
Administrators
Int
and the F
ood
of the
Fo
10267 071900

5
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. Remove the upper rear panel and rotate the control thermostat
knob fully counterclockwise to the “OFF”position and replace
the panel.
2. Connect the dispenser to the power source and turn-on the water
supply.
3. Water will automatically flow into the tank to the proper level
and shut-off. This will take approximately 10 minutes.
4. Disconnect the dispenser from the power source, remove the
upper rear panel and place the control thermostat knob fully
clockwise to the “ON”position, and replace the panel.
5. Connect the dispenser to the power source and wait approxi-
mately twenty minutes for the water in the tank to heat.
6. On models with ready indicator, the indicator will glow when the
proper water temperature for use is achieved.
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 4-40 screws at the sides 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. Bunn-O-Matic has a syphon assem-
bly available (#12440.0000) for this purpose.
NOTE - The dispenser must be full 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.
WALL MOUNTED INSTALLATION
If the dispenser is wall mounted, the bottom of the dispenser should be at the same height as a counter or
table top. Use B.O.M. part #12542.0000 for side mounted Wall Bracket Kit or # 13125.0001 for front mounted
Wall Bracket Kit .
SUPPORT FOR LARGE RECEPTACLES
CAUTION: If the dispenser is to be used with larger receptacles such as pitchers or pots, those receptacles must
be adequately supported during dispensing of hot water to avoid spillage of very hot water. This support may be
provided by a table or counter top, or use B.O.M. part #12599.0000 Shelf Kit
P1781
10267 071900

6
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 Tech-
nical Service Department.
•Inspection, testing, and repair of electrical equipment should be performed only by qualified service person-
nel.
•All electronic components have 120 –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
2. Safety overflow switch
Remedy
(A) Check the terminal block for the cor-
rect voltage. It should be:
a.) 100 to 120 volts ac across the black and
white terminals for 100 to 120 volt mod-
els,
b.) 200 to 240 volts ac across the red and
black terminals for 200 to 240 volt models
c.) 230 volts ac across the red and black
terminals for 230 volt models.
(B) Check circuit breakers or fuses.
Refer to Service –safety overflow switch
for testing procedures. See page 11.
10267 071900

7
TROUBLESHOOTING (cont.)
Problem Probable Cause Remedy
Automatic refill will not operate
after drawing hot water.
Water flows into the tank con-
tinuously (Dispenser discon-
nected from power source).
Water flows into the tank con-
tinuously (Dispenser connected
to power source).
Water is cold.
1. No water
2. Water strainer/flow control
3. Safety overflow switch
4. Liquid level system
5. Solenoid valve
1. Solenoid valve
1. Liquid level system
1. Control thermostat
2. Safety overflow switch
3. Limit thermostat
4. Tank heater
5. Temperature control
Check plumbing and shut-off valves.
(A) Direction of flow arrow must be point-
ing towards dispenser.
(B) Remove the strainer/flow control and
check for obstructions. Clear or replace.
Refer to Service –safety overflow switch
for testing procedures. See page 11.
Refer to Service –liquid level board for test-
ing procedures. See page 15.
Refer to Service –solenoid valve for test-
ing procedures. See page 12.
Refer to Service –solenoid valve for test-
ing procedures. See page 12.
Refer to Service –liquid level board for test-
ing procedures. See page 15.
Control thermostat must be in the “ON”
position.
Refer to Service –safety overflow switch
for testing procedures. See page 11.
Refer to Service –limit thermostat for test-
ing procedures. See page 10.
Refer to Service –tank heater for testing
procedures. See page 13.
Refer to Service –control thermostat for
testing procedures. See page 14.
CAUTION –Do not eliminate or bypass limit thermostat. Use only B.O.M. replacement part #23717.0001.
10267 011599

8
TROUBLESHOOTING (cont.)
Problem Probable Cause Remedy
Water boils continuously.
Dispenser is making unusual
noises.
Ready indicator will not light.
(when temperature is within 4°
of its selected setting.)
1. Temperature control
2. Lime build-up
1. Solenoid valve
2. Plumbing lines
3. Water supply
1. Temperature control
2. Ready Indicator LED
Refer to Service –control thermostat for
testing procedures. See page 14.
Inspect the tank assembliy for excess lime
deposits. Delime as required.
The nut on top of the solenoid valve must
be tight or it will vibrate during operation.
Plumbing lines should not be resting on the
counter top.
(A) The dispenser must be connected to a
cold water line.
(B) Water pressure to the dispenser must
not be higher than 90 psi (620 kPa). Install
a regulator if necessary to lower the work-
ing pressure to approximately 50 psi (345
kPa).
Refer to Service –control thermostat for
testing procedures. See page 14.
Replace the indicator LED.
CAUTION – Tanks and tank components should be delimed reglarly depending on local water conditions. Exces-
sive mineral build-up on stainless steel surfaces can initiate corrosive reactions resulting in serious leaks.
10267 011599

9
SERVICE
This section provides procedures for testing and
replacing various major components used in this dis-
penser 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 replace-
ment of any component. 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 three 4-40 slotted-head screws.
WARNING – Inspection, testing, and repair of electrical
equipment should be performed only by qualified ser-
vice personnel. Disconnect the dispenser from the
power source when servicing, except when electrical
tests are required and the test procedure specifically
states to connect the dispenser to the power source.
Contactor ............................................................ 17
Limit Thermostat ................................................ 10
Liquid Level Board .............................................. 15
Safety Overflow Switch ....................................... 11
Solenoid Valve .................................................... 12
Tank Heater ........................................................ 13
Control Thermostat............................................. 14
O
N
CAUTION
!
FailureToComplyVoidsWarranty!
HotWater Systems –Water Tank Will Fill
AutomaticallyWhen Unit Is ConnectedToPower!
CoffeeBrewers–Fill The WaterTank In
AccordanceWithThe Installation Instructions!
DONOT
Turn On The Tank Heater Switch
Until Water Comes From Opened Faucet!
W
O
N
OFF
ON
STOP
READNOTICE
DISCONNECTFROMPOWERSOURCE
BEFOREREMOVALOFANYPANELOR
REPLACEMENTOFANYCOMPONENT!
WARNING
!
O
N
CAUTION
!
FailureToComplyVoidsWarranty!
HotWater Systems–Water Tank Will Fill
AutomaticallyWhen Unit Is Connected ToPower!
CoffeeBrewers –Fill TheWater TankIn
AccordanceWith TheInstallation Instructions!
DONOT
Turn On The Tank Heater Switch
Until Water Comes From Opened Faucet!
HAZARDOUS
VOLTAGE
DISCONNECTFROM
POWERSOURCE
BEFOREREMOVING!
WARNING
O
N
OFF
ON
STOP
READNOTICE
Fillwatertankbeforeturning-on
thermostatorconnectingappliance
topowersource.
Donotusenearcombustibles.
Follownational/localelectricalcodes.
Electricallygroundthechassis.
Useonlyonaproperlyprotected
circuitcapableoftheratedload.
FAILURETOCOMPLYRISKSEQUIPMENT
DAMAGE,FIRE,ORSHOCKHAZARD
READTHEENTIREOPERATINGMANUAL
INCLUDINGTHELIMITOFWARRANTYAND
LIABILITYBEFOREBUYINGORUSINGTHISPRODUCT
THISAPPLIANCEISHEATEDWHENEVER
CONNECTEDTOAPOWERSOURCE
00831.0000A5/88©1988BUNN-O-MATICCORPORATION
WARNING
!
Thisequipmentistobeinstalledto
complywiththeBasicPlumbingCodeof
theBuildingOfficialsandCode
AdministratorsInternational,Inc.(BOCA)
andtheFoodServiceSanitationManual
oftheFoodandDrugAdministration(FDA).
DISCONNECTFROMPOWERSOURCE
BEFOREREMOVALOFANYPANELOR
REPLACEMENTOFANYCOMPONENT!
WARNING
!
The check valve, safety overflow switch, solenoid
valve, overflow tube temperature sensor, control ther-
mostat and terminal block are located at the rear of the
dispenser. Access is gained by removing the upper and
lower rear panels. The upper is attached with six 8-32
slotted-head screws. The lower is attached with four
8-32 slotted-head screws. The middle panel must not
be removed from the dispenser.
P1770
P1770
10267 011599

10
SERVICE (cont.)
Limit Thermostat
Location:
The limit thermostat is located on the tank lid.
To test the limit thermostat, access will also be needed
to the terminal block located at the rear of the dispenser.
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 ter-
minals.
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. 2 when reconnecting the wires.
Test Procedure:
1. Disconnect the dispenser from the power source.
2. Remove the blue/black wire at the limit thermostat
coming from the control thermostat.
3. Check the voltage across the blue/black wire and
the black wire at the tank heater with a voltmeter.
Connect the dispenser to the power source. The
indication must be:
a.) 100 to 120 volts ac for 100 to 120 volt models,
b.) 200 to 240 volts ac for 200 to 240 volt models,
c.) 230 volts ac for 230 volt models.
4. Disconnect the dispenser from the power source.
If voltage was present as described, reconnect the blue/
black wire and proceed to #5.
If voltage was not present as described, refer to the
Wiring Diagrams and check the dispenser wiring har-
ness.
FIG. 1 LIMIT THERMOSTAT
FIG. 2 LIMIT THERMOSTAT WIRING
BLK to Control Thermostat
BLK to Tank Heater
or
Contactor
P1793
P1776
Reset
10267 071900

11
SERVICE (cont.)
Safety Overflow Switch
Location:
The safety overflow switch is located inside the rear of
the dispenser inside the copper overflow cup.
Test Procedure:
1. Once voltage is verified at the power source, check
for continuity across the safety overflow 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 safety overflow
switch is operating properly.
If continuity is not present as described, replace the
safety overflow switch.
FIG. 3 SAFETY OVERFLOW SWITCH
FIG. 4 SAFETY OVERFLOW WIRING
RED to BLK Wire from
Terminal Block
RED to BLK Wire from
Liquid Level Board #2
P1793
P1777
Removal and Replacement:
1. Disconnect the black wires from the safety over-
flow 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 safety overflow switch to operate properly.
5. Install the nut beneath the copper overflow cup.
Be sure not to overtighten.
6. Reconnect the wires, FIG. 4.
10267 011599

12
SERVICE (cont.)
Solenoid Valve
Location:
The solenoid valve is located inside the rear of the dis-
penser on the right side near the bottom.
6. 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.
7. 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 block-
age 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 sole-
noid valve.
4. Remove the two 8-32 slotted-head screws holding
the solenoid valve and mounting bracket to the
component bracket.
5. Lift-out the solenoid valve.
6. Remove the two 10-32 slotted-head screws hold-
ing the solenoid valve to its mounting bracket.
7. Securely install the new solenoid valve to its mount-
ing 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 so-
lenoid valve.
10. Reconnect the wires, FIG. 6.
Fillwatertankbeforeturning-on
thermostatorconnectingappliance
topowersource.
Donotusenearcombustibles.
Follownational/localelectricalcodes.
Electricallygroundthechassis.
Useonlyonaproperlyprotected
circuitcapableoftheratedload.
FAILURETOCOMPLYRISKSEQUIPMENT
DAMAGE,FIRE,ORSHOCKHAZARD
READTHEENTIREOPERATINGMANUAL
INCLUDINGTHELIMITOFWARRANTYAND
LIABILITYBEFOREBUYINGORUSINGTHISPRODUCT
THISAPPLIANCEISHEATEDWHENEVER
CONNECTEDTOAPOWERSOURCE
00831.0000A5/88©1988BUNN-O-MATICCORPORATION
WARNING
!
Test Procedure:
1. Disconnect the dispenser from the power source
and turn-off the water supply to the dispenser.
2. Check the voltage across the solenoid valve coil
terminals with a voltmeter. Connect the dispenser
to the power source. The indication must be:
a.) 100 to 120 volts ac for 100 to 120 volt models,
b.) 200 to 240 volts ac for 200 to 240 volt models,
c.) 230 volts ac for 230 volt models,
after a delay of approximately 5 seconds.
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 har-
ness.
4. Remove both wires from the solenoid valve coil
terminals.
5. Check for continuity across the solenoid valve coil
terminals.
If continuity is present as described, reconnect the
wires and proceed to #6.
If continuity is not present as described, replace the
solenoid valve coil.
FIG. 5 SOLENOID VALVE
FIG. 6 SOLENOID VALVE WIRING
BLU to Liquid Level #2
WHI or RED to Terminal Block
P1778
P1779
10267 011599

13
SERVICE (cont.)
Tank Heater
Location:
The tank heater is located in the tank lid.
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:
a.) 100 to 120 volts ac for 100 to 120 volt models,
b.) 200 to 240 volts ac for 200 to 240 volt models,
c.) 230 volts ac for 230 volt models.
3. Disconnect the dispenser from the power source.
If voltage is present as described, proceed to #4.
If voltage is not present as described, replace the tank
heater.
FIG. 7 TANK HEATER
FIG. 8 TANK HEATER WIRING
BLK to Limit
Thermostat or
BLK to Contactor
WHI to Terminal
Block or RED to
Contactor
P1780
P1793
4. Remove the tank heater from the tank lid and in-
spect it for cracks in the sheath.
If the sheath shows no sign of damage, proceed to #5.
If the sheath is damaged, replace the tank heater.
5. Check for continuity across the tank heater termi-
nals.
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 nec-
essary.
5. Securely install the new tank heater. Be certain of a
watertight seal.
6. Reconnect the wires, FIG. 8.
10267 011599

14
FIG. 10 THERMOSTAT WIRING
BLU/BLK to Limit Thermostat
BLK to Terminal Block P1782
SERVICE (cont.)
Thermostat
Location: The mechanical thermostat is located inside
the upper rear panel. To test the thermostat, access
will also be needed to the terminal block located inside
the bottom access panel.
Test Procedure:
1. Disconnect the dispenser from the power source.
2. Check the voltage across the black wire on the ther-
mostat and the white or red wire at the terminal
block with a voltmeter. Connect the dispenser to
the power source. The indication must be:
a.) 100 to 120 volts ac for 100 to 120 volt models,
b.) 200 to 240 volts ac for 200 to 240 volt models,
c.) 230 volts ac for 230 volt models.
3. Disconnect the dispenser from the power source.
If voltage is present as described, proceed to #4.
If voltage is not present as described, refer to the Wir-
ing Schematics and check the dispenser wiring har-
ness.
4. Check the voltage across the blue/black wire on
the thermostat and the white or red wire at the ter-
minal block with a voltmeter when the thermostat
is turned “ON”(fully clockwise). Connect the dis-
penser to the power source. The indication must
be as described in step 2. Voltage must not be in-
dicated when the thermostat is turned “OFF”(fully
counterclockwise).
5. Disconnect the dispenser from the power source.
P1781
If voltage is present as described, the thermostat is
operating properly.
If voltage is not present as described, replace the ther-
mostat.
Removal and Replacement:
1. Remove both wires from the thermostat terminals.
2. Remove the top lid from the dispenser to gain ac-
cess to the thermostat bulb.
3. Remove the thermostat bulb by firmly pulling up
on the capillary tube at the tank. This will disen-
gage the grommet from the tank.
4. Remove the two #6-32 screws holding the ther-
mostat to the mounting bracket.
5. Fasten the new thermostat to the mounting bracket.
NOTE: Make sure that the capillary tube is away from
any electrical termination and is not kinked.
6. Slide the grommet to the red mark on the capillary
tube.
7. Insert the bulb through the hole in the tank and
press the grommet firmly and evenly so that the
groove in the grommet fits into the tank.
8. Refer to FIG. 10 when reconnecting the wires.
9. Readjust the thermostat dial as required.
FIG. 9 THERMOSTAT
10267 071900

15
SERVICE (cont.)
Liquid Level Board
Location:
The liquid level board is located inside the lower
panel.
Test Procedure:
1. Disconnect the dispenser from the power source.
2. Remove the blue wire from terminal 1 and the pink
wire from terminal 4 of the circuit board.
3. Check the voltage across terminals 2 and 3 with a
voltmeter. Connect the dispenser to the power
source. Turn the thermostat knob to the “ON”po-
sition (fully clockwise). The indication must be:
a.) 100 to 120 volts ac for 100 to 120 volt models,
b.) 200 to 240 volts ac for 200 to 240 volt models,
c.) 230 volts ac for 230 volt models.
4. Disconnect the dispenser from the power source.
If voltage is present as described, proceed to #5.
If voltage is not present as described, refer to the wir-
ing diagrams and check the wiring harness.
FIG. 11 LIQUID LEVEL BOARD
P1783
5. Reconnect the blue wire to terminal 1.
6. Carefully connect a piece of insulated jumper wire
to terminal 4. Keep the other end of this wire away
from any metal surface of the dispenser.
7. Check the voltage across terminals 1 & 3 with a
voltmeter. Connect the dispenser to the power
source. Turn the thermostat knob to the “ON”po-
sition (fully clockwise). The indication must be:
a.) 100 to 120 volts ac for 100 to 120 volt models,
b.) 200 to 240 volts ac for 200 to 240 volt models,
c.) 230 volts ac for 230 volt models,
after a delay of approximately 5 seconds.
8. Touch the free end of jumper wire to the dispenser
housing. The indication must be 0.
9. Move the jumper wire away from the dispenser
housing. The indication must again be:
a.) 100 to 120 volts ac for 100 to 120 volt models,
b.) 200 to 240 volts ac for 200 to 240 volt models,
c.) 230 volts ac for 230 volt models,
after a delay of approximately 5 seconds.
10. Disconnect the dispenser from the power source
and remove the jumper wire from terminal 4.
If voltage is present as described, the level control
board is operating properly, proceed to #11.
If voltage is not present as described, replace the level
control board.
11. Reconnect the pink wire to terminal 4.
12. Gently pull the probe out of the tank and inspect
for corrosion. Replace it if necessary.
13. Place the probe so that neither end is in contact
with any metal surface of the dispenser.
14. Check the voltage across terminals 1 & 3 with a
voltmeter. Connect the dispenser to the power
source. Turn the thermostat knob to the “ON”po-
sition (fully clockwise). The indication must be:
a.) 100 to 120 volts ac for 100 to 120 volt models,
b.) 200 to 240 volts ac for 200 to 240 volt models,
c.) 230 volts ac for 230 volt models,
after a delay of approximately 5 seconds.
10267 071900

16
15. Move the probe's flat end to the dispenser hous-
ing. The indication must be 0.
16. Move the probe's flat end away from the dispenser
housing. The indication should again be:
a.) 100 to 120 volts ac for 100 to 120 volt models,
b.) 200 to 240 volts ac for 200 to 240 volt models,
c.) 230 volts ac for 230 volt models.
17. Disconnect the dispenser from the power source.
If voltage is present as described, reinstall the probe,
the level control board and level probe are operating
properly.
If voltage is not present as described, check the pink
probe wire.
SERVICE (cont.)
Liquid Level Board (cont.)
FIG. 12 LIQUID LEVEL BOARD WIRING
BLU to Solenoid (T-1)
BLK to Overflow Safety Switch (T-2)
WHI to Terminal Block (T-3)
PNK to Level Probe (T-4)
P1784
Removal and Replacement:
1. Remove all wires from the level control board.
2. Remove two #8-32 screws holding level control
board and mounting bracket to the component
bracket.
3. Install the new level control board and mounting
bracket to the component bracket.
4. Refer to FIG. 12 when reconnecting the wires.
10267 071900

17
Location:
The contactor is located on the component
bracket inside the lower rear panel.
Test Procedures:
1. Disconnect the dispenser from the power source.
2. Disconnect the black wire from the contactor coil
to the limit thermostat and black wire from the red
wire on the main harness on two wire 240V mod-
els.
3. Check the voltage across the red wire and black
wire with a voltmeter. The indication must be:
a.) 240 volts ac for 240 volt models,
b.) 230 volts ac for 230 volt models.
4. Disconnect the dispenser from the power source.
If voltage is present as described, proceed to #5.
If voltage is not present as described refer to the Wir-
ing Diagrams and check the wiring harness.
5. Check for continuity between the left and right ter-
minals on the contactor coil.
If continuity is present as described, reconnect the
wires and proceed to #6
If continuity is not present as described, replace the
contactor.
6. Check the voltage across the upper left terminal
and the upper right terminal on the contactor with
a voltmeter. Connect the dispenser to the power
source. The indication must be:
a.) 240 volts ac for 240 volt models,
b.) 230 volts ac for 230 volt models.
7. Disconnect the dispenser from the power source.
If voltage is present as described, proceed to #8.
If voltage is not present as described, refer to the wir-
ing diagrams and check the wiring harness.
8. Check for continuity across the terminals on the
left side of the contactor by manually closing the
contacts. Continuity must not present when the
contact is released.
9. Check for continuity across the terminals on the
right side of the contactor by manually closing the
contacts. Continuity must not be present when the
contact is released.
If continuity is present as described, the contactor is
operating properly.
If continuity is not present as described, replace the
SERVICE (cont.)
Contactor
FIG. 13 CONTACTOR
P1785
10267 071900

18
BLK to left Tank
Heater
RED to Terminal Block(L2)
BLK to Terminal
Block (L1)
RED to Right
Tank Heater
BLK to Limit
Thermostat
RED from Main Harness
P1725
FIG.14 CONTACTOR WIRING
contactor.
Removal and Replacement:
1. Disconnect all the wires from the contactor.
2. Remove the two #8-32 screws securing the
contactor to the contactor mounting bracket, re-
move contactor and protective shield. Discard
SERVICE (cont.)
Contactor (cont.)
contactor.
3. Install new contactor with shield between mount-
ing bracket and contactor and secure with two #8-
32 screws
4. Refer to Fig. 14 and reconnect the wires.
10267 011599

19
4312
LIQUID
LEVEL
BOARD
BLU/BLK
TANK HEATER
120 VOLTS A C
2 WIRE
SINGLE PHASE 10243.0000D 1/99 © 1987 BUNN-O-MATIC CORPORATION
SCHEMATIC WIRING DIAGRAM H5M
L1 N
BLK
BLK
BLK
SOL
WHI
GREEN
BLU WHI
WHI
BLK BLK
(PROBE)
P
N
K
REDRED
BLK
SW&
THERMOSTAT
OPTIONAL
READY INDICATOR
OVERFLOW
PROTECTION SWITCH
LIMIT
THERMOSTAT
4312
LIQUID
LEVEL
BOARD
BLK BLKBLK
BLK
SW&
THERMOSTAT
10262.0000C 1/99 © 1987 BUNN-O-MATIC CORPORATION
SCHEMATIC WIRING DIAGRAM H5M
L1 L2
BLK
SOL
GREEN
BLU
BLK BLK
(PROBE)
P
N
K
REDRED
RED
BLU/BLK
BLK RED
RED
BLK
N.O. N.O.
KRED
RED
RED
TANK HEATER
208 or 240 VOLTS A C
2 WIRE
SINGLE PHASE
OPTIONAL
READY INDICATOR
OVERFLOW
PROTECTION SWITCH
LIMIT
THERMOSTAT
WIRING DIAGRAMS
10267 011599

20
WIRING DIAGRAMS
4312
LIQUID
LEVEL
BOARD
BLK
SW&
THERMOSTAT
10262.0001A 11/99 © 1999 BUNN-O-MATIC CORPORATION
SCHEMATIC WIRING DIAGRAM H5MA, 230V CE
L1 L2
BLK
SOL
GREEN
BLU
BLK BLK
(PROBE)
P
N
K
REDRED
RED
BLU/BLK
BLK RED-12BLK-12
N.O. N.O.
KRED
RED
RED
TANK HEATER
230 VOLTS A C
2 WIRE
SINGLE PHASE
OVERFLOW
PROTECTION SWITCH
LIMIT
THERMOSTAT
THERMAL
FUSE
THERMAL
FUSE
N.C.
10267 071900