Subzero BI Series User manual

Icemaker Information 77
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BI
Service Manual

Page 2
Icemaker Information
6-2
#7005333 - Revision C - September, 2010
Built-In (BI) Series
Built-In (BI) Series
ICEMAKER SYSTEM INFORMATION
Built-In Series units utilizes a Japan-Servo ® icemaker.
Its operation is not complex, but understanding its com-
ponents and operation cycle will assist a Service
Technician in make proper diagnosis of problems.
TO AVOID ELECTRIC SHOCK, ALWAYS DISCON-
NECT ELECTRICAL POWER TO UNIT WHEN SER-
VICING ICEMAKER.
NOTES:
• Water fill time/volume in the BI Series is controlled by
the electronic control ‘s micriprocessor. The micro-
processor observes the volumetric flow through the
water valves via a low DC voltage signal from the
flow meter, with every one revolution of the turbine
inside the flow meter equaling 0.02 oz (0.5 ml) The
electronic control instructs the valve to remain open
long enough to deliver approximately 3.5 oz (105 ml)
of water. This timeframe will vary depending on
water pressure.
• Adjsuting the water fill adjusting screw at the icemak-
er will have no effect on water fill time/volume.
• The “ICE MAKER” key on the control panel activates
the icemaker system. If the ice cube icon is not dis-
played on the LCD, the icemaker system is OFF.
• To allow ice to freeze fully and reduce effects of low
water pressure, the electronic control disables the ice-
maker system for 45 minutes after each ice harvest.
• Power to the freezer lights, is monitored to help con-
trol icemaker operation. If the freezer door is open,
power to the icemaker is interrupted.
• The icemaker system is disabled when the unit is in
Sabbath Mode.
ICEMAKER COMPONENTS
Following are descriptions that explain the function of
each icemaker component. The components are dia-
gramed in Figure 6-1 on the next page.
Support - The support is the housing around the elec-
trical components and wire connections. The support is
attached to the ice mold.
Mounting Plate - The drive motor, holding switch,
water valve solenoid switch, timing gear, timing cam
and water fill adjusting screw are attached to the metal
mounting plate. The mounting plate is then attached to
the support.
Drive Motor - AC voltage supplied to the drive motor
causes the motor to operate. The motor has a single
output shaft with a small gear. The motor gear
drives/spins the timing gear.
Timing Gear - The timing gear is driven/spun by the
drive motor gear and is attached to the timing cam.
Timing Cam - The timing cam is attached to the tim-
ing gear and the ice ejector is inserted into the center of
the timing cam. As the timing cam rotates, high and
low spots on the cam operate the water valve solenoid
switch and the holding switch. The timing cam also
moves the lever arm side to side and rotates the ice
ejector.
Ice Mold - The ice mold is where the eight crescent
shaped ice cubes are formed.
Mold Heater - The mold heater uses 165 watts to
thaw the ice free from the mold.
Ice Ejector - The drive end of the ice ejector is “D”
shaped to fit into the “D” shaped hole in the timing cam.
It has eight blades which rotate and sweep the ice from
the mold cavities during the ejection phase of the cycle.
Ice Stripper - The stripper is attached to the dumping
side of the mold, serving as a decorative side cover and
it also prevents ice from falling back into the mold.
Bearing / Inlet - The bearing / inlet is attached to the
ice mold, opposite the support. Water enters the bear-
ing / inlet and is directed to the ice mold. The
bearing/inlet also supports the ice ejector at the end
opposite the timing cam.
Thermostat - The thermostat is a single-pole, single-
throw, bi-metal switch. At 15°F (-9°C) ± 3° it closes,
starting the ice ejection phase.
Thermal-Mastic - A substance similar in appearance
to grease that is applied between the thermostat and
the ice mold. Its purpose is to increase thermal con-
ductivity between the mold and the thermostat.
Lever Arm and Shut-off Arm - The lever arm is
moved side to side by two revolutions of the timing
cam. As it moves, it raises and lowers the shut-off arm
and operates the shut-off switch to control the quantity
of ice production. If the shut-off arm comes to rest on
top of the ice in the storage bin during either revolution,
the shut-off switch will remain open, stopping ice pro-
duction at the end of that revolution.
Water Valve Solenoid Switch - A single-pole, double-
throw type switch that allows electricity to the water
valve solenoid, opening the valve, during the fill cycle.
Holding Switch - A single-pole, double-throw type
switch that assures completion of a revolution once the
icemaker has been energized.
Shut-off Switch - A single-pole, double-throw type
switch that stops ice production when the ice bin is full.
TCO (Thermal Cut Out) - The TCO is thermal protec-
tion device in the wire harness that would open in the
event of mechanical failure, thus protecting against over
heating. (The TCO is not shown in diagram.)

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Icemaker Information
6-3 #7005333 - Revision C - September, 2010
Built-In (BI) Series
Built-In (BI) Series
GEAR MOUNTING PLATE
COVER
ICE STRIPPER
FILL CUP
EJECTOR
BAIL ARM (LONG)
MOLD BODY
HOLD SW
BRACKET
ARM LEVER
SUPPORT
MOTOR
CAM
HARNESS
THERMOSTAT
WATER SW
SHUT-OFF
Figure 6-1. Diagram of Icemaker Components
(For reference only. Individual components are not available for Service. If problems with the icemaker are
discovered, the entire icemaker must be replaced)
ICEMAKER OPERATION
The following series of electrical schematics illustrate a
typical icemaker cycle of operation. Below each
schematic is a diagram indicating the approximate loca-
tion of the ice ejector and ice level arm during the
phase the schematic indicates.
Freeze Phase of Ice Making Cycle (See Figure 6-2)
• The ice mold is filled with water.
• The thermostat is open.
• No icemaker components are energized.
Figure 6-2. The Freeze Phase
APPROXIMATE POSITION
OF ICE EJECTOR AND
ICE LEVEL ARM
DURING OPERATION
115 VOLTS
60 CYCLES
SHUT-OFF SWITCH THERMOSTAT
MOLD HEATER
WATER
SOLENOID
SOLENOID SWITCH
MOTOR
HOLDING SWITCH
NO
NC
C
NC
NC
NO
NO
C
C
TCO
ICE MOLD
ICE BUCKET
WATER

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Icemaker Information
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#7005333 - Revision C - September, 2010
Built-In (BI) Series
Built-In (BI) Series
Start of the First Revolution (See Figure 6-3)
• The water in the ice mold has turned to ice.
• At 15°F (-9°C) ± 3° the thermostat closes.
• The mold heater is energized through the thermo-
stat.
• The drive motor is started through the thermostat
and “normally closed” terminal of the holding
switch.
• The ice ejector begins to turn and the shut-off arm
begins to rise.
Figure 6-3. Start of First Revolution
APPROXIMATE POSITION
OF ICE EJECTOR AND
ICE LEVEL ARM
DURING OPERATION
115 VOLTS
60 CYCLES
SHUT-OFF SWITCH THERMOSTAT
MOLD HEATER
WATER
SOLENOID
SOLENOID SWITCH
MOTOR
HOLDING SWITCH
NO
NC
C
NC
NC
NO
NO
C
C
TCO
ICE MOLD
ICE BUCKET
ICE
Figure 6-4. First Revolution Continued
APPROXIMATE POSITION
OF ICE EJECTOR AND
ICE LEVEL ARM
DURING OPERATION
115 VOLTS
60 CYCLES
SHUT-OFF SWITCH THERMOSTAT
MOLD HEATER
WATER
SOLENOID
SOLENOID SWITCH
MOTOR
HOLDING SWITCH
NO
NC
C
NC
NC
NO
NO
C
C
TCO
ICE MOLD
ICE BUCKET
ICE
First Revolution Continued (See Figure 6-4)
• The holding switch is tripped by the timing cam to
“normally open” thus holding power to the motor.
• The mold heater remains energized through the
thermostat.
• The shut-off arm begins to rise.

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Icemaker Information
6-5 #7005333 - Revision C - September, 2010
Built-In (BI) Series
Built-In (BI) Series
First Revolution Continued (See Figure 6-5)
• The ice ejector reach the ice in the mold.
• The ice releases from the mold as the ejector
blades begin to rotate the cubes out.
• The drive motor remains energized through the
holding switch.
• The mold heater remains energized through the
thermostat.
• As the shut-off arm rises, the shut off switch is
tripped to “normally closed”, and then the shut-off
arm begins to lower.
Figure 6-5. First Revolution Continued
APPROXIMATE POSITION
OF ICE EJECTOR AND
ICE LEVEL ARM
DURING OPERATION
115 VOLTS
60 CYCLES
SHUT-OFF SWITCH THERMOSTAT
MOLD HEATER
WATER
SOLENOID
SOLENOID SWITCH
MOTOR
HOLDING SWITCH
NO
NC
C
NC
NC
NO
NO
C
C
TCO
ICE MOLD
ICE BUCKET
ICE
Figure 6-6. First Revolution Continued
APPROXIMATE POSITION
OF ICE EJECTOR AND
ICE LEVEL ARM
DURING OPERATION
115 VOLTS
60 CYCLES
SHUT-OFF SWITCH THERMOSTAT
MOLD HEATER
WATER
SOLENOID
SOLENOID SWITCH
MOTOR
HOLDING SWITCH
NO
NC
C
NC
NC
NO
NO
C
C
ICE MOLD
ICE BUCKET
ICE
TCO
First Revolution Continued (See Figure 6-6)
• The ice has released from the mold.
• The motor remains energized through the holding
switch.
• The shut-off arm is lowered and the shut off switch
is tripped to “normally open”.
• The water valve solenoid switch is tripped by the
timing cam, but the solenoid is not energized
because the thermostat is still closed and energiz-
ing the mold heater. (Electric current follows the
path of least resistance.)

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Icemaker Information
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#7005333 - Revision C - September, 2010
Built-In (BI) Series
Built-In (BI) Series
End of First Revolution (See Figure 6-7)
• The water valve solenoid switch is tripped by the
timing cam back to “normally open.”
• The timing cam trips the holding switch to “normally
close,” which ends the first revolution, but the ther-
mostat is still closed, so the motor is again started.
• The mold heater remains energized through the
thermostat.
Figure 6-7. End of First Revolution
APPROXIMATE POSITION
OF ICE EJECTOR AND
ICE LEVEL ARM
DURING OPERATION
115 VOLTS
60 CYCLES
SHUT-OFF SWITCH THERMOSTAT
MOLD HEATER
WATER
SOLENOID
SOLENOID SWITCH
MOTOR
HOLDING SWITCH
NO
NC
C
NC
NC
NO
NO
C
C
ICE MOLD
ICE BUCKET
ICE
TCO
Figure 6-8. Start of Second Revolution
APPROXIMATE POSITION
OF ICE EJECTOR AND
ICE LEVEL ARM
DURING OPERATION
115 VOLTS
60 CYCLES
SHUT-OFF SWITCH THERMOSTAT
MOLD HEATER
WATER
SOLENOID
SOLENOID SWITCH
MOTOR
HOLDING SWITCH
NO
NC
C
NC
NC
NO
NO
C
C
ICE MOLD
ICE BUCKET
ICE
TCO
Start of Second Revolution:(See Figure 6-8)
• The water valve solenoid switch is tripped by the
timing cam back to “normally open.”
• The timing cam trips the holding switch to “normally
close,” which ends the first revolution, but the ther-
mostat is still closed, so the motor is again started.
• The mold heater remains energized through the
thermostat.

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Icemaker Information
6-7 #7005333 - Revision C - September, 2010
Built-In (BI) Series
Built-In (BI) Series
Second Revolution Continued (See Figure 6-9)
• The mold heater has warmed the thermostat, so the
thermostat opens, and the mold heater is de-ener-
gized.
• If the shut-off arm comes to rest on top of the ice in
the storage bin (as illustrated), so the shut-off
switch will remain in the “normally closed” position.
• The motor remains energized through the holding
switch.
Figure 6-9. Second Revolution Continued
APPROXIMATE POSITION
OF ICE EJECTOR AND
ICE LEVEL ARM
DURING OPERATION
115 VOLTS
60 CYCLES
SHUT-OFF SWITCH THERMOSTAT
MOLD HEATER
WATER
SOLENOID
SOLENOID SWITCH
MOTOR
HOLDING SWITCH
NO
NC
C
NC
NC
NO
NO
C
C
ICE MOLD
ICE BUCKET
ICE
ICE
TCO
Figure 6-10. Second Revolution Continued
APPROXIMATE POSITION
OF ICE EJECTOR AND
ICE LEVEL ARM
DURING OPERATION
115 VOLTS
60 CYCLES
SHUT-OFF SWITCH THERMOSTAT
MOLD HEATER
WATER
SOLENOID
SOLENOID SWITCH
MOTOR
HOLDING SWITCH
NO
NC
C
NC
NC
NO
NO
C
C
ICE MOLD
ICE BUCKET
ICE
ICE
TCO
Second Revolution Continued (See Figure 6-10)
• The water valve solenoid switch is tripped by the
timing cam. This time the solenoid is energized
because the thermostat is open. The water sole-
noid is open for approximately seven seconds, fill-
ing the ice mold with water.
• the mold heater is energized through the solenoid
switch and holding switch.

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Icemaker Information
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#7005333 - Revision C - September, 2010
Built-In (BI) Series
Built-In (BI) Series
Figure 6-11. End of Ice Making Cycle
APPROXIMATE POSITION
OF ICE EJECTOR AND
ICE LEVEL ARM
DURING OPERATION
115 VOLTS
60 CYCLES
SHUT-OFF SWITCH THERMOSTAT
MOLD HEATER
WATER
SOLENOID
SOLENOID SWITCH
MOTOR
HOLDING SWITCH
NO
NC
C
NC
NC
NO
NO
C
C
TCO
ICE MOLD
ICE BUCKET
WATER
ICE
ICE
End of Ice making Cycle (See Figure 6-11)
• The water valve solenoid switch is tripped by the
timing cam back to “normally open” ending the
water fill.
• The timing cam trips the holding switch to “normally
close,” which ends the second revolution.
• The thermostat is still open, so it does not start the
drive motor.
• If the shut-off arm has come to rest on top of the
ice in the storage bin (as illustrated), the shut-off
switch remains in the “normally closed” position.
This interrupts power from reaching the thermostat,
until sufficient ice has been removed from the stor-
age bin allowing the shut-off arm to lower.
NOTE: To allow ice to freeze fully and reduce effects of
low water pressure, the electronic control system dis-
ables the icemaker system for 45 minutes after each ice
harvest.
Figure 6-12. Stopping Icemaker
Arm DOWN,
Icemaker will Operate
Arm UP,
Icemaker will Stop
MANUALLY STOPPING ICE PRODUCTION
Ice production can be manually stopped two ways:
1. Press the “ICE MAKER” key on the control panel so
that the ice cube icon is not displayed on the LCD.
2. Position the ice-level/shut-off arm in the up/OFF
position (See Figure 6-12).

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Icemaker Information
6-9 #7005333 - Revision C - September, 2010
Built-In (BI) Series
Built-In (BI) Series
MANUALLY STARTING THE ICEMAKER
NOTE: To allow ice to freeze fully and reduce effects of
low water pressure, the electronic control disables the
icemaker system for forty-five (45) minutes after each
ice harvest. To bypass this 45 minute dwell for service
purposes, press the the “ICE MAKER” key at the con-
trol panel to switch the system OFF, then again to
switch it back ON.
Manual Start Procedure:
1. Pry the icemaker front cover from the support using
a flat-blade screwdriver or coin.
2. With a flat-blade screwdriver, turn the drive gear
counterclockwise until the holding switch is activat-
ed, completing the circuit to the drive motor (this
will be about a 1/8 turn). (See Figure 6-13) The
icemaker will then complete its cycle automatically.
NOTE: If after 1/4 turn the icemaker is not running
on its own, it may be in the 45 minute dwell period
or there is an electrical or mechanical problem.
Figure 6-13. Manually Start Icemaker
Turn Drive Gear
Counterclockwise

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Icemaker Information
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#7005333 - Revision C - September, 2010
Built-In (BI) Series
Built-In (BI) Series
ICEMAKER FAULT TESTING
Bypass 45-minute dwell by pressing ICE MAKER key to OFF,
then again to ON. Now, depress the freezer light switch and
manually start icemaker by turning driver gear counter-clock-
wise with screwdriver.
1 If icemaker starts & finishes cycle:
(NOTE: If >15°F, icemaker will only complete 1 revolu-
tion.)
a. Visually inspect electrical connections at icemaker &
valve. Repair if necessary.
b. Check valve operation with test cord, if doesn't open,
replace valve.
c. Check thermostat. (Open: 48°F ±6°, Close: 15°F ±3°).
Replace icemaker if defective.
d. With icemaker in park position, check solenoid switch
terminals "C" & "NO" for continuity. With ejector
between 8:00 & 10:00 position, check solenoid switch
terminals "C" & "NC" for continuity. If no continuity for
either terminal check, replace icemaker.
2. If icemaker starts but does not finish cycle:
a. With icemaker in park position check holding switch ter-
minals "C" & "NC" for continuity. Then with icemaker
ejector between 10:00 & 12:00, check holding switch
terminals "C" & "NO" for continuity. If no continuity for
either terminal check, replace icemaker. (Refer to
enclosed wiring diagram)
b. With icemaker in park position check shut-off switch
terminals "C" & "NO" for continuity. With ejector
between 12:00 & 2:00 check shut-off switch terminals
"C" & "NC" for continuity. If no continuity for either ter-
minal check, replace icemaker.
c. Check mold heater for 75-85Ω. If outside range,
heater is bad, replace icemaker. If heater checks OK,
thermostat is bad, replace icemaker.
3 If icemaker motor does NOT start:
a. Lower shutoff arm
b. Check motor operation with test cord. If motor doesn't
run, replace icemaker.
c. Check power to and from icemaker rocker switch (if
present). Reconnect or repair connection or replace
switch as necessary.
d. Check for power from control board to icemaker. If
power is present check & repair connection. If no
power, replace control board.
QUICK REFERENCE
• Water Fill Time: May vary by water pressure
• Fill Tube Heater Ohm: 2850-3890Ω
• Mold Heater Ohm: 75-85Ω
• Water Valve Ohm: 160-165Ω
• Thermostat Open/Close - Open: 48°F ±6° Close: 15°F ±°3
• Water Pressure Needed: 30 -120 psi constant
NOTE: This is a filtered water specification as non-filtered
systems ae are rated at 20-100 psi.
ICEMAKER TROUBLESHOOTING
No / Slow Ice Production
1 Ice maker system switched OFF. Switch system ON.
2 Shut off arm in up/OFF position. Move to ON position.
3 Freezer too warm. Check temp’s & see troubleshooting
guide in service manual.
4 Poor airflow over icemaker. Remove obstructions.
5 Ice cube jam. Remove ice.
6 Water froze in inlet tube. Remove ice from tube. Check
for power from control board to fill tube heater; Fill tube
heater = 2850-3890Ω.
7 Water supply not constant 20-120 psi. Instruct customer.
8 Water line to unit pinched/kinked/clogged. Repair line.
9 Saddle valve not installed correctly. Reposition.
10 Saddle valve not fully open. Open valve fully.
11 Icemaker wire/connections loose/broken. Repair wiring.
12 Water valve wire/connections loose/broken. Repair wiring.
13 Defective water valve. Valve =160-165Ω. Replace valve.
14 Thermostat wire/connections loose/broken. Repair wiring.
15 TCO overheat or short. Fix cause or replace icemaker.
16 See Icemaker Fault Testing.
No Water Fill
1 Water supply switched OFF. Switch supply water line ON.
2 Water line to unit pinched/kinked/clogged. Repair line.
3 Saddle valve not installed correctly to supply line.
Reposition.
4 Water froze in inlet tube. Remove ice from tube. Check
for power from control board to fill tube heater; Fill tube
heater = 2850-3890Ω.
5 Water valve wire/connections loose/broken. Repair wiring.
6 Defective water valve. Valve =160-165Ω. Replace valve.
Overflows / Ice Block Forms in Bucket / Oversized Cubes
1 Icemaker not level. Level icemaker.
2 Unit not level. Level unit
3 Water supply not constant 20-120 psi. Instruct customer.
4 Water froze in inlet tube. Remove ice from tube. Check
for power from control board to fill tube heater; Fill tube
heater = 2850-3890Ω.
5 Defective water valve. Valve =160-165Ω. Replace valve.
6. Improper fill signal from control board; replace control
board.
Ice Cubes Hollow or Small
1 Icemaker not level. Level icemaker.
2 Unit not level. Level unit
3 Water supply not constant 20-120 psi. Instruct customer.
4 Too little thermalmastic on thermostat. Add thermalmastic.
5 Defective thermostat (Open = 48°F ±6°, Close = 15°F ±3°).
Replace icemaker.
6. Improper fill signal from control board; replace control
board.
Too much Ice
1 Shut off arm/linkage bent, broken or disconnected. Repair,
replace o reconnect arm/linkage.
2 If ejector blades rotate with arm in up/OFF position =
Icemaker faulty. Replace icemaker.