Sharp R-8320E, Service Manual

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CONVECTION COOKING CONDITION
PREHEATING CONDITION
Program desired convection temperature by touching the
“CONVECTION” pad and the temp. pad.
When the “COOK” pad touched, the following operations
occur: (Figure 3)
1. The COOK and CONV indicators light.
2. LO C appears in the display and Convection Fan Symbol
flashes on and off.
40 C appears in the display when oven temperature has
reached
3. The coil of shut-off relay is energized by the
control unit.
3-l.
The relay contacts close to provide a current path
to the damper motor.
3-2. The damper motor is energized and damper is
moved to the closed position, opening the
damper switch contacts.
3-3. The opening of the damper switch contacts sends
a signal to the control unit de-energizing shut-off
relay (RY4) and opening the circuit to the damp-
er motor.
4. The coil of shut-off relay is energized.
4-l. The relay contacts (A) close to provide a current
path to the oven lamps.
4-2. The relay contacts (B) close to provide a current
path to the turntable motor.
5. The coil of shut-off relay (RY3) is energized.
The relay contacts close to provide a current path to
the cooling fan motor.
6. The coil of shut-off relay is energized.
The relay contacts close to provide a current path to
the convection motor.
7. The coil of heater relay is energized by the control unit.
8. The heater relay contacts close to provide a current
path to the heating element.
9. The 240 volts A.C. is supplied to the heating element.
10. When the oven temperature reaches the selected pre-
heat temperature, the following operations occur:
10-l. The Convection Fan Symbol stops flashing on
and off, and begins to rotate.
10-2. The heater relay is de-energized by the control
unit temperature circuit and thermistor,
ning the circuit to the heating element.
A beep signal will sound four times.
The preheat temperature has been reached.
10-4. The oven will continue to function for 15
minutes, turning on and off, as needed to main-
tain the selected preheat temperature.
The oven will shut-down completely after 15
minutes.
CONVECTION COOKING CONDITION
When the preheat temperature is reached, a beep signal
will sound four times indicating that the holding tempe-
rature has been reached in the oven cavity, open the door
and place the food to be cooked in the oven.
Then program desired cooking time and convection tem-
perature by touching the NUMBER pad, “CONVECTION”
pad and Temperature pad.
When the “COOK” pad is touched, the following opera-
tions occur:
1. The COOK, Convection Fan Symbol and CONV
indicators light.
The numbers of the digital readout start the count
down to zero.
2. The oven lamps, turntable motor, cooling fan motor
and convection motor are energized.
3. The heating element is not energized. But, if the oven
temperature was lower than the selected temperature,
the heater relay is energized, and the 240 volts A.C.
is supplied to the heating element to return to the
selected cooking temperature.
When the selected temperature is reached, the heater
is de-energized, but the other components remain in
operation.
4. Upon completion of the cooking time, the audible
signal will sound, and oven lamps, turntable motor,
cooling fan motor and convection motor are
energized. At that time if the oven temperature is
approximately
or above, the shut-off relay
(RY3) remains ON (judged at the control unit by
thermistor operation) and the cooling fan motor
continues to operate cooling the oven cavity.
Or, when the oven temperature reaches approxi-
mately 120°C or above at the completion of cooking
time, the same operation as described above will take
place, the cooling fan will continue to run.
When the oven temperature drops below approxi-
mately
the contacts of the shut-off relay
open and the cooling fan motor is de-energized, and the
oven will revert to the OFF condition.
The heater will’ cycle on and off to maintain the
selected temperature.
5. At the end of the convection cook cycle, shut-off re-
lay (RY4) is energized turning on the damper motor.
The damper is returned to the open position, closing
the damper switch contacts which send a signal to
the control unit, de-energizing shut-off relay (RY4).
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