GE PGS908 Technical Service Manual page 64

The lock switch circuit "tells" the control if the
lock motor is in the unlocked or locked position or
somewhere in between. There are two lock switches
mounted to and operated by the lock motor.
The lock switch circuit is from the control, through
one of the lock switches (switch 2 for unlocked or
switch 1 for locked), back to the control. If neither
switch is closed, and the oven temperature is below
600°F (315°C), control will energize the lock motor
circuit until the correct switch closes to complete
the circuit. (If circuit to the correct switch is open,
lock motor will run continuously with the oven
below 600°F [315°C]).
CLEAN CYCLE AND LOCK SEQUENCE
1. Program the clean cycle:
• Press "SELF-CLEAN" pad. 4 hours (4:00) appears
on the time display. (Cleaning time can be
changed from the 4-hour starting point by
pressing the "SELF-CLEAN" pad a second time.)
• After "START" has been pressed, the word "ON"
illuminates in red to indicate the cycle has
begun.
2. Locking the door:
• After programming the clean cycle and pressing
START pad, the control energizes the lock relay.
Voltage (120 VAC) is applied to the lock motor
circuit. Oven door must be closed before lock
motor can run. "LOCK DOOR" will fl ash and
control will beep until the door is closed.
• The lock motor begins to revolve and turns a
cam mounted to the motor shaft.
• The words "LOCKED DOOR" will fl ash on and off
on the display while the lock motor is in motion.
• As the cam revolves about 1/2 revolution
(approximately 12 seconds), it has moved the
lock "hook" into a corresponding slot in the oven
door which secures the door.
• The movement of the cam has also closed lock
switch 1 which "tells" the control the door is
locked. The control then removes power from
the lock motor circuit by de-energizing the lock
relay.
• The lock motor stops and lock switch 1 is held
closed by the cam through the clean cycle.
• The words "LOCKED DOOR" stop fl ashing and
remain illuminated in the display.
• The word "ON" illuminates in the display.
3. During the clean cycle:
• The broil relay closes (audible "click") and the
broil burner begins to heat. The broil burner only
will operate during the fi rst 30 minutes of the
clean cycle followed by the bake burner only
during the remaining time.
• As the clean cycle progresses and the
temperature of the oven control area rises, the
cooling fans are activated.
• A normally closed thermal switch is mounted
on a bracket in front of the cooling fan. This
switch is in the lock switch circuit and will
open the lock switch circuit in the event of an
over-temperature condition in the control area
(caused by a stalled fan, fan switch failure or
similar condition). An -F2- (over-temperature)
failure code will appear on the control if this
switch opens while the oven is above 600°F
(315°C). With the oven between 400°F (204°C)
to 600°F (315°C), the clean cycle will be
cancelled by the opening of the switch and
the control will revert back to the time-of-day
mode. Below 400°F (204°C), the lock motor will
revolve continuously and the words "LOCKED
DOOR" will fl ash on the control until the circuit is
reestablished.
• The oven will cycle to maintain an average
clean temperature of 840°F (449°C) on PGS908
models and 830°F (443°C) on PGS968 and
PGS975 models.
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