Cool Down Cycle (Kx Thermostat Or Solid State Control); Vc4Ec, Vc6Ec (Computer Control) - Vulcan-Hart VC4EC Service Manual

FULL SIZE ELECTRIC CONVECTION OVENS - ELECTRICAL OPERATION
1. With the power switch turned ON, power is
supplied to "Cook" timer terminal 1.
2. Set "Cook" timer to desired time .
A. Contacts 1 & 3 close, timer motor is
energized and timing "down" begins.
3. Time expires on "Cook" timer .
A. Contacts 1 & 3 open, timer motor is de-
energized and timing stops.
B. Contacts 1 & 4 close.
1) Buzzer energized and sounds.
NOTE: The buzzer continues to sound until
the timer dial is set to the OFF position or
additional time is set.
Cool Down Cycle
(KX Thermostat or Solid State Control)
1. Conditions.
A. Oven is ON.
B. Oven cavity temperature needs to be
lowered.
C. Doors are open (door switch contacts
OPEN).
D. Fan speed switch (S3) set to "Hi".
2. Power Switch (S1) turned to COOL DOWN.
A. Power ON light (Amber) goes out.
B. Convection fan motor energized.
NOTE: Fan speed switch (S3) can be set
to operate at high or low fan speed.
3. If doors are CLOSED (door switch contacts
CLOSED):
A. Power ON light (Amber) comes ON.
B. 1CON coil is energized but heating
elements are not powered.
C. Component cooling fan energized.
D. Power is supplied to:
1) "Cook" timer terminal 1. If a time is
dialed, timer will operate and buzzer
will sound when timer reaches zero.
2) Oven cavity light switch (S3) wire #1.
Turns cavity lights ON/OFF; does not
affect "Cool down" cycle.
4. The oven will remain in this condition until the
power switch (S1) is turned to the OFF or ON
position.

VC4EC, VC6EC (Computer Control)

Schematic diagram 6536 will be used to explain the
electrical sequence of operation or both the "Cook"
cycle and the "Cook and Hold" cycle.
Cook Cycle
1. Conditions.
A. Oven connected to correct voltage and is
properly grounded.
B. Power switch (S1) OFF.
C. Computer control is setup properly and
ready to use.
NOTE: The set point temperature of the
computer control will be the last
temperature that was set.
D. High limit thermostat CLOSED.
E. Oven doors closed (door switch contacts
CLOSED).
F. Oven cavity temperature below 140°F.
2. Power switch (S1) turned ON.
A. 1CON coil energized.
B. 24VAC transformer (T1) is energized.
1)
C. Component cooling fan energized.
D. Power is connected to:
1)
2)
3)
3. Computer control senses oven cavity
temperature through probe input. With the oven
cavity temperature below set point, the output
from pin C3-2 is activated.
A. Oven "Heat Light" on the control comes
ON.
B. 2CON coil energized.
1)
C. The controls 5VDC output from pins C2-2
(-) and C2-8 (+) is activated and SSR1
relay is energized.
1)
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Computer control is energized and
performs a power ON self test before
energizing outputs. If the control
passes self test, then the outputs are
energized and operation sequence
continues. If control does not pass self
test then the corresponding error code
is displayed.
Terminal 1 on solid state relay 1
(SSR1 - load side) and solid state
relay 2 (SSR2 - load side).
Pin 3 (C3-3) on computer control
(input "IN-2").
Oven cavity light switch (S2). Turns
cavity lights ON/OFF; does not affect
"Cook" cycle.
Heating elements powered and
heating starts.
Convection fan motor is energized
(High speed).
F25105 (Rev. A, October 2007)