SUB-ZERO 7028783 Ice Maker Instruction Manual

SUB-ZERO 7028783 Ice Maker

ICEMAKER SYSTEM INFORMATION
This Series unit uutilisesa Nidec-Servo ® icemaker. Its operation is not complex, but understanding its componentsand operation cycle will assist a Service Technician in making a proper diagnosis of problems.

TO AVOID ELECTRIC SHOCK, ALWAYS DISCON-NECT ELECTRICAL POWER TO THE UNIT WHEN SERVICING THE ICEMAKER.

NOTES

• The “ICE MAKER” key on the control panel activates the ice maker system. If the ice cube icon is not displayed on the LCD, the icemaker system is OFF.
• To allow ice to freeze fully and reduce the 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

• The following are descriptions that explain the function of each icemaker component. The components are diagrammed in Figure 5-1 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 mould.
• 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 – 115 volts AC 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 Mould – The ice mould is where the eight crescent-shaped ice cubes are formed.
• Mould Heater – The mould heater uses 165 watts to thaw the ice free from the mould.
• 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 mouldd, serving as a decorative side cov,er, and it also prevents ice from falling back into the mould.
• Bearing / Inlet – The bearing/inlet is attached to the ice mould, opposite the support. Water enters the bearing/inlet and is directed to the ice mould. The TheThe
• 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 mould. Its purpose is to increase thermal conductivity between the mould 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 production 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 energised.
• 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 a thermal protection device in the wire harness that would open in the event of mechanical failure, thus protecting against overheating (The TCO is not shown in the diagram.)

Figure 5-1. Diagram of Icemaker Components
(For reference only. Individual components are not available for the Service. If problems with the icemaker are discovered, the entire icemaker must be replaced.

ICEMAKER OPERATION

The following series of electrical schematics illustrate a typi cal 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 5-2)

• The ice mould is filled with water.
• The thermostat is open.
• No icemaker components are energised.

Start of the First Revolution (See Figure 5-3)

• The water in the ice mould has turned to ice.
• At 15°F (-9°C) ± 3° the thermostat closes.
• The mould heater is energised through the thermostat.
• The drive motor is started through the thermostat and the “normally closed” terminal of the holding switch.
• The ice ejector begins to turn, and the shut-off arm begins to rise.

First Revolution Continued (See Figure 5-4)

• The holding switch is tripped by the timing cam to “normally open,” thus holding power to the motor.
• The moulded heater remains energised through the thermostat.
• The shut-off arm begins to rise.

First Revolution Continued (See Figure 5-5)

• The ice ejector reaches the ice in the mould.
• The ice releases from the mould as the ejector blades begin to rotate the cubes out.
• The drive motor remains energised through the holding switch.
• The mould heater remains energised 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.

First Revolution Continued (See Figure 5-6)

• The ice has been released from the mould.
• The motor remains energised 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 energised because the thermostat is still closed and energising the mould heater. (Electric current follows the path of least resistance.)

End of First Revolution (See Figure 5-7)

• The water valve solenoid switch is tripped by the timing cam back to “normally open.”
• The timing cam trips the holding switch to “normally closed,” which ends the first revolution, but the thermostat is still closed, so the motor is again started.
• The mould heater remains energised through the thermostat.

Start of Second Revolution:(See Figure 5-8)

• The water valve solenoid switch is tripped by the timing cam back to “normally open.”
• The timing cam trips the holding switch to “normally closed,” which ends the first revolution, but the thermostat is still closed, so the motor is again started.
• The moulded heater remains energised through the thermostat.

Second Revolution Continued (See Figure 5-9)

• The mould heater has warmed the thermostat, so the thermostat opens, and the mould heater is de-energised.
• If the shut-off arm comes to rest on top of the ice in the storage bin (as illustrated), the shut-off switch will remain in the “normally closed” position.
• The motor remains energised through the holding switch.

Second Revolution Continued (See Figure 5-10)

The water valve solenoid switch is tripped by the timing cam. This time, the solenoid is energised because the thermostat is open. The water solenoid is open for approximately seven seconds, filling the ice mould with water.
Moulded and energised through the solenoid switch and holding switch.

End of ice-making Cycle (See Figure 5-11)

• 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 closed,” 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 storage 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 disablesthe icemaker system for 45 minutes after each ice harvest.

MANUALLY STOPPING ICE PRODUCTION

Ice production can be manually stopped in 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 5-12).

MANUALLY STARTING THE ICEMAKER
NOTE: To allow ice to freeze fully and reduce the 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 “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 activated, completing the circuit to the drive motor (this will be about a 1/8 turn). (See Figure 5-13)
3. 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.

ADDITIONAL ICEMAKER SERVICE NOTES

• Manual icemaker water fill time/volume adjustment is not possible on the Integrated Series, as this is a function of the electronic control system and cannot be changed.
• The icemaker system is de-energised for three (3) minutes after a door/drawer switch is opened, then closed. This feature is to help prevent an ice harvest if someone has removed the ice bucket for a brief period.
• Because of this three (3) minute icemaker power interruption, the door/drawer switch(es) must be closed for three (3) minutes after they are opened to check voltage to the icemaker.

ICEMAKER FAULT TESTING

Bypass the 45-minute dwell by pressing the ICE ON/OFF key to OFF, then again to ON. Now, depress the icemaker rocker switch behind the ice bucket (if present) and manually start the icemaker by turning the driver gear counter-clockwise with a screwdriver.

1. Ifthe  icemaker starts & finishes the cycle:
   (NOTE: If >15°F, icemaker will only complete 1 revolution.)
   • a. Visually inspect electrical connections at the cemaker & valve. Repair if necessary.
   • b. Check valve operation with test cord; if it doesn’t open, replace.
   • c. Check thermostat. (Open: 48°F ±6°, Close: 15°F ±3°). Replace the icemaker if defective.
   • d. With the icemaker in park position, check the solenoid switch terminals “C” & “NO” for continuity. With the ejector between 8:00 & 10:00 position, check solenoid switch terminals “C” & “NC” for continuity. If no continuity for either terminal check, replace the icemaker.
2. If the icemaker starts but does not finish the cycle:
   • a. With the icemaker in the park position, check the holding switch terminals “C” & “NC” for continuity. Then, withthe icemaker ejector between 10:00 & noon, check holding switch terminals “C” & “NO” for continuity. If no continuity for either terminal check, replace the cemaker. (Refer to enclosed wiring diagram)
   • b. With the icemaker in park position, check shut-off switch terminals “C” & “NO” for continuity. With the ejector between noon & 2:00, check the shut-off switch terminals “C” & “NC” for continuity. If no continuity for either terminal check, replace the icemaker.
   • c. Check the mould heater for 115-125Ω. If outside the range, the heater is bad; replace the icemaker. If the heater checks OK, the thermostat is bad; replace the thermostat.
3. If the icemaker motor does NOT start:
   • a. Lower shutoff arm
   • b. Check motor operation with test cord. If the motor doesn’t run, replace the ice maker.
   • c. Check power to and from the icemaker rocker switch (if present). Reconnect or repair the connection or replace the switch as necessary.
   • d. Check for power from the control board to the icemaker. If power is present, check the repair of the connection. If no power, replace the control board.

QUICK REFERENCE

• Water Fill Time: 6.3 +0.6/-0.4 seconds
• Fill Tube Heater Ohm: 2850-3890Ω
• Mould Heater Ohm: 115-125Ω
• Water Valve Ohm: 160-165Ω
• Thermostat Open/Close – Open: 48°F ±6° Close: 15°F ±°3
• Water Pressure Needed: 20-120 psi constant
• NOTE: This is a non-filtered water specification, as water Filters are generally rated at 35-120 psi.

ICEMAKER TROUBLESHOOTING

No / Slow Ice Production

1.  Ice maker system switched OFF. Switch the system ON.
2. Shut off the arm in the up/OFF position. Move to the ON position.
3. The freezer is too warm. Check temps & see the troubleshooting guide in the service manual.
4. Poor airflow over the icemaker. Remove obstructions.
5. Ice cube jam. Remove ice & check water fill setting.
   • a. Water fill setting is too low (< 6 seconds). Adjust fill setting.
   • b. Water fill setting is too high (> 7 seconds). Adjust fill setting.
6. Water froze in the inlet tube. Remove ice from the tube. Check for power from the control board to the fill tube heater; Fill tube heater = 2850-3890Ω.
7. Water supply not constant, 20-120 psi. InstInstruct thetomer.
8. The water line to the unit is kinked/clogged. Repair the water line.
9. Supply line: Saddle valve not installed correctly. Reposition.
10. Saddle valve not fully open. Open the valve fully.
11. Icemaker wire/connections loose/broken. Repair wiring.
12. Water valve wire/connections loose/broken. Repair wiring.
13. Defective water valve. Check valve Ohms, Replace valve. The
14. Thermostat wire/connections are loose/broken. Repair wiring.
15. TCO overheat or shorts. Fix the cause or replace the icemaker.
16. See Icemaker Fault Testing.

No Water Fill

1. Water supply switched OFF. Switch the supply water line ON.
2. The water line tothe unit is kinked/clogged. Repair the water line.
3. Saddle valve not installed correctly onto to supply line. Reposition.
4. Water froze in the inlet tube. Remove ice from the tube. Check for power from the control board to fill the tube heater; Fill the tube heater = 2850-3890Ω.
5. Water valve wire/connections loose/broken. Repair wiring.
6. Defective water valve. Check valve Ohms, Replace valve.

Overflows / Ice Block Forms in Bucket / Oversized..
The icemaker is not level. Level icemaker.

1. Unit not level. Level unit
2. Water supply not constant, 20-120 psi. Instruct the ustomeWater customersomere in the inlet tube.
3. Remove ice from the tube. Check for power from the control board to the fill tube heater; Fill tube heater = 2850-3890Ω.
4. Water fill settings are too low (< 6 seconds). Adjust fill setting. The water fill setting is too high (> 7 seconds). Adjust fill setting.
5. Defective water valve. Check valve Ohms, Replace valve.

Ice Cubes Hollow or Small

1. The icemaker is not level. Level icemaker.
2. Unit not level. Level unit
3. Water supply not constant, 20-120 psi. Instruct the customer.
4. The water fill setting is too low (< 6 seconds). Adjust fill setting.
5. Too little thermal mass on the thermostat. Addthermoplasticc.
6. Defective thermostat (Open = 48°F ±6°, Close = 15°F ±3°).
7. Replace Icemaker.

Too much Ice

1. Shut off arm/linkage bent/broken. Repair or replace the arm linkage.
2. If ejector blades rotate withthe arm in the up/OFF position = Icemaker is faulty. Replace the icemaker.