GE DPGT750EC/GC - Manual (Page 34)

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Note: Proper leveling of the dryer is vital for
accurate sensor drying. Excessive rearward
adjustment will cause clothes to tumble toward
the rear of the drum, preventing contact with the
senor rods, thus producing a false dryness
reading.
Testing the Moisture Sensor Circuit
1. Place the dryer in Factory Test Mode:
a. Press HOME, then HELP.
b. Press and hold the HELP and START/
STOP pads simultaneously for 3 seconds.
A dry sensor rod circuit should display a voltage of
4.75 VAC or higher under MOISTURE(S) test.
2. Wet a cloth and place it across the sensor
rods. The display voltage should drop to
1.0 VAC or less if the circuit is working
correctly.
Moisture Sensor
The moisture-sensing circuit consists of two
sensor rods mounted in the drum front beneath
the lint filter opening.
• The sensor rods are connected to the main
control board. The rods are spaced about
½ in. apart, which creates an open circuit to
the control.
• The control board utilizes a low-voltage
capacitor that charges to approximately 5
VDC when the circuit is open and discharges
to less than 1 VDC when the circuit is shorted.
• When wet clothes tumble across the two
rods, the clothes create a very low resistance
between the rods, which discharges the
capacitor.
• As the clothes become dry, their resistance
value increases and the charge across the
capacitor builds to approximately 5 VDC.
Sensor Rods
Ignitor and Flame Detector
• When the electronic control calls for heat,
120 VAC is supplied to the ignitor.
• The flame detector, which is in series with the
ignitor, is closed.
• When the ignitor reaches a high enough
temperature, the flame detector opens.
• The electronic control senses the opening of
the detector and energizes the gas valves.
Testing the Ignitor and Flame Detector Circuit
1. Place the dryer in Factory Test Mode:
a. Press HOME, then HELP.
b. Press and hold the HELP and START/
STOP pads simultaneously for 3 seconds.
2. Press START/STOP to begin the test.
• The FLAME SENSOR test will display
whether the detector is open or closed.
• In the OFF position, the flame detector is
closed (room temperature/low heat).
In the
ON position, the flame detector is open
(hot).