Whirlpool KRFC704FSS - Page 20

For Service Technician Use Only
DIAGNOSTICS
1-16
n
French-Door Boom Mount Refrigerator
During a Fill Cycle, the GF2 board supplies 115 VAC to P12-4,
opening the Isolaon Valve. At the same me, the GF2 board
supplies 115 VAC to P12-6, opening the FC Ice Maker Valve.
Aer 10 seconds, the GF2 board to ends the Fill Cycle. The GF2
board removes power to the valves, to end the Fill Cycle.

The refrigerator contains an Ice Maker (IM) in the le RC Door.
Some models have a second IM in the Freezer.
Both are Twist Tray Ice Makers, using twisng acon of the motor
to break and dump the ice. No heaters are needed for the IM.
All ming, logic, and control is outsourced to the control board
powering the IM.

The In-Door IM is controlled by the Dispenser UI and is composed
of the Ice Maker Module.

The Ice Maker module includes the Gear Box, Ice Bin Switch, Ice
Box Temperature Sensor, and Ice Tray Temperature Sensor.

The Gear Box has a 12.7 VDC Motor which drives the Tray Gear,
turning the Ice Tray and operang the Bail Arm through an
associated worm gear. The Bail Arm is used to detect if the Ice
Bucket is full.
The Ice tray posion is determined by a wiper arm aached to
the tray gear. As the tray gear turns, the wiper runs over a
resistor ladder. As the wiper moves over the resistance ladder,
the resistance changes. The resistance sensed at any given me
tells the Dispenser UI the posion of the Ice Tray.

The Ice Bin Switch is a spring loaded, normally open switch. The
switch is closed by the Ice Bucket when inserted. The switch must
be closed for the Ice Maker to Harvest ice.

The Ice Box Thermistor is mounted on the Ice Maker. It senses Ice
Box temperature as an input into the Refrigeraon System.

The Ice Tray Temperature Sensor is mounted to the underside of
the Ice Tray. It reads the temperature of the Ice Tray to ensure
the ice is fully frozen.

The standard Ice Making process consists of the following cycles:
• Homing
• Filling
• Freezing
• Harvest

When power is inially applied to the Ice Maker, it will move
to the home posion. In the Home Posion, the Ice Tray is
horizontal and ready to receive water.

During the Fill Cycle, water is dispensed for 10 seconds. This lls
the Ice Tray with about 3.2 oz. (100 ml) of water. At the beginning
of the ll cycle, the ll tube heater is forced o. The ll tube
heater remains o for 20 minutes. Aer this me delay, the ll
tube heater will energize and remain energized for 90 minutes, or
unl the beginning of the next Fill Cycle, whichever comes rst.

During Freezing, the IM is waing for me and temperature
condions to be met. These condions vary between the Door
Ice Maker and the Freezer Ice Maker.
For the Door Ice Maker, in the Normal mode, an 80 minute freeze
mer must be sased, and the Ice Tray temperature must read
15°F (-9.4°C) before the ice is ready for Harvest.
In Max Ice mode, a 60 minute freeze mer must be sased, and
the Ice Tray temperature must read 15°F (-9.4°C) before the ice
is ready for Harvest. The Max Ice feature only aects the In-Door
Ice Maker, and not the Freezer Ice Maker.
During Freezing, the freeze mer will be paused any me an
RC door is opened. When the RC door is closed, addional me
will be added to the mer. The addional me added is equal to
the length of me the door was open. The mer will then begin
counng down again.
Wiper Arm
Resistance
Ladder
Ice Box
Thermistor