– 16 –
Mullion Removal
1. Remove two T15 Torx screws at the top of the
door securing the wire cover, then remove the
cover.
2. Disconnect the mullion connector.
NOTE: If removing the mullion to replace the door,
proceed to step 4.
3. Remove the wires from the connector. The
connector will need to be reused for the
replacement mullion.
4. Remove two T15 Torx screws from the top hinge.
NOTE: If removing the mullion to replace the door,
proceed to step 6.
5. Slide
the
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6.
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hinge.
Diagnosing
The heater can be checked at the main board or
at the mullion connector. The mullion heater has a
resistance of 21.5 ohms.
Main board check
• J4 pin 2 (brown) - J2 pin 7 (violet) = 13 VDC
Mullion connector check
• Red and black wires under the wire cover.
NOTE: If no voltage is found at the main board or
the connector, it may be necessary to disconnect
the humidity sensor for 20 minutes to ensure the
main board is supplying voltage to the circuit.
The vertical mullion is located on the left fresh
food door. The mullion contains a heater which is
supplied with 13 VDC from the main board. Heater
operation is regulated by the humidity sensor
reading.
The vertical mullion heater is controlled by the
main board software logic. The main control
board takes into account the percentage of room
humidity, room temperature, and either freezer
or fresh food temperatures. As the room humidity
increases, the amount of voltage supplied to the
heaters is increased to keep the mullion surfaces
from sweating. At lowest humidity, the articulating
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is controlled automatically by the board based on
thermistor and humidity sensor input.
Every 20 minutes, the main control board utilizes
a duty cycle to monitor and react to the condition
of the humidity sensor. Control board corrections,
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during the duty cycle. If the control detects a failed
humidity sensor the mullion heater will be operated
at 100%.
Vertical Mullion
