Dacor DCM24B Service Manual page 11

DCM24B
DCM24R
DCM24S
2. Heat potatoes. Moisture and
humidity is emitted rapidly.
You can smell the aroma as it
cooks.
3. Sensor detects moisture and
humidity and calculates
cooking time and variable
power.
Cooking Sequence.
1. Touch ENSOR COOK, SENSOR REHEAT or
POPCORN pad.
NOTE: The oven should not be operated on sensor cooking
modes immediately after plugging in the unit. Wait
two minutes before cooking on SENSOR COOK,
SENSOR REHEAT or POPCORN.
2. Select desired Sensor setting.
3. Touch START pad.
The coil of shut-off relay (RY1, RY6) is energized, the
oven lamp and cooling fan motor are turned on, but the
power transformer is not turned on.
4. After about 16 seconds, the cook relay (RY-2) is
energized. The power transformer is turned on,
microwave energy is produced and first stage is started.
The 16 seconds is the cooling time required to remove
any vapor from the oven cavity and sensor.
NOTE: During this first stage, do not open the door or touch
STOP CLEAR pad.
5. When the sensor detects the vapor emitted from the
food, the display switches over to the remaining cooking
time and the timer counts down to zero. At this time, the
door may be opened to stir food, turn it or season, etc.
6. When the timer reaches zero, an audible signal sounds.
The shut-off relay and cook relay are de-energized and
the power transformer, oven lamp, etc. are turned off.
7. Opening the door or touching the STOP CLEAR pad, the
time of day will reappear on the display and the oven will
revert to an OFF condition.
AUTO BROIL/ AUTO ROAST/ AUTO BAKE
AUTO BROIL/ ROAST/ BAKE will automatically compute the
oven temperature, microwave power and cooking time for
baking, roasting and broiling. Set the desired program by
touching the AUTO BROIL/ ROAST/ BAKE pad, and number
pad. Enter the weight by touching the Number pads. When the
START pad is touched, the following operations occur:
1. The COOK indicator will light and the Convection Fan
Symbol will rotate.
2. The cooking time will appear on the display and start
counting down to zero. The cooking time is adjusted
automatically according to the weight of the food.
3. The shut-off relays (RY1, RY5 and RY6) are energized,
turning on the oven lamp, turntable motor, cooling fan
motor and convection motor. The power supply voltage
is applied to the heating element.
4. Now, the oven is in the convection cooking mode.
5. When the oven temperature has reached the
programmed convection temperature, the oven goes
into the programmed cooking mode.
6. At the end of the COMPU BROIL/ ROAST/ BAKE cycle,
the damper is returned to the open position and the oven
AUTO DEFROST COOKING
The AUTO DEFROST key is a special function key to
defrost meats and poultry faster and better. AUTO DE-
FROST automatically defrosts roast beef, etc.. When the
AH SENSOR
AUTO DEFROST is selected and the food weight is entered
by using the AUTO DEFROST pad, the oven will cook
according to the special cooking sequence.
FIRE SENSING FEATURE (MICROWAVE MODE)
This model incorporates a sensing feature which will stop
the oven's operation if there is a fire in the oven cavity during
microwave cooking. This is accomplished by the LSI repeat-
edly measuring the voltage across the temperature meas-
urement circuit (thermistor) during it's 32-seconds time
base comparing the obtained voltage measurements. If the
most recent voltage measured is 300mV greater than the
previous voltage measured, the LSI judges it as a fire in the
oven cavity and switches off the relays to the power trans-
former, fan motor and convection motor. The LSI also stops
counting down and closes the damper door so that no fresh
air will enter the oven cavity. Please refer to the following
section for a more detailed description.
Operation
Please refer to the timing diagrams below.
1. The thermistor operates within a 32-seconds time base
2. The above procedure is repeated. If the difference between
3. Once the fire sensor feature has shut the unit down, the
IMPORTANT:
During sensor cooking operation, the fire sensing op-
eration sequence will not begin until the AH sensor has
detected vapors and initiated a sensor cooking cycle.
This is because the operation of the convection fan
would interfere with the AH sensor's vapor detection.
8
will go to the off condition. The cooling fan will remain on
until the oven has cooled.
and it is energized for three (3) seconds and off for 29
seconds. Two (2) seconds after the thermistor is
energized, the voltage across the temperature
measurement circuit is sampled by the LSI and twenty
one (21) seconds after the thermistor is cut off the LSI
turns on the cooling fan for six (6) seconds.
the first voltage measured (in step 1) and the voltage
measured when the procedure is repeated (step 2) is
greater than 300mV the LSI makes the judgment that there
is a fire in the oven cavity and will switch off the relays to the
power transformer, fan motor and convection motor. The
LSI also stops counting down and closes the damper door
so that no fresh air will enter the oven cavity.
programmed cooking cycle may be resumed by pressing
the "START" pad or the unit may be reset by pressing the
"CLEAR" pad.
0 2 3 24 30 32 (sec.)
6 sec.
CONVECTION
MOTOR ON
OFF
3 sec.
THERMISTOR
ON
OFF
ON
Sensing
Voltage
OFF
Sensing the voltage across temperature measurement circuit.
64 (sec.)