Vulcan-Hart ML-126743 Service Manual page 41

VC4E & VC6E Series Full Size Electric Convection Ovens - ELECTRICAL OPERATION
2) Pin 3 (C3-3) on computer control (input
"IN-2").
3) Oven cavity light switch (S2). Turns
cavity lights ON/OFF; does not affect
"Cook" cycle.
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) Heating elements powered and
heating starts.
C. The controls 5VDC output from pins C2-2 (-)
and C2-8 (+) is activated and SSR1 relay is
energized.
1) Convection fan motor is energized
(High speed).
4. Oven reaches set point temperature.
A. Computer control de-activates the output
from pin C3-2.
1) 2CON coil de-energized.
a. Power removed from heating
elements and heating stops.
B. Oven "Heat Light" on the control goes out.
C. Oven "Ready Light" on the control comes
ON.
D. Electronic beeper sounds momentarily.
5. The oven will continue to cycle on the computer
control until the doors are opened or power
switch (S1) is turned to the OFF or COOL DOWN
position.
Temperature and Time Cycle (Cooking)
NOTE: The computers internal "Cook" timer operates
independently of the heating cycle. Additional time
can be set or the timer can be stopped and re-started
throughout the cooking cycle. Refer to the Instructions
Manual for specific operating instructions of the oven
Computer Control.
Roast and Hold Cycle
NOTE: For a detailed explanation of the "Roast &
Hold" mode, refer to the Instructions Manual F31159
as outlined under SETTING THE OVEN FOR ROAST
& HOLD and ROAST & HOLD OPERATION. In "Roast
& Hold" mode, the operation of the computer control
is identical to the normal Cook Cycle with these
exceptions:
1. Oven "Roast & Hold" light on the control comes
ON.
2. Convection fan will operate at Low speed,
throughout the "Roast & Hold" cycle.
A. The computer control 5VDC output from
pins C2-2 (-) and C2-8 (+) is de-activated
and SSR1 relay is de-energized.
1)
B. The computer control 5VDC output from
pins C2-1 (-) and C2-8 (+) is activated and
SSR2 relay is energized.
1)
3. Beeper sounds momentarily to indicate the end
of first stage cooking (oven operates normally at
the temperature and time selected until time
expires).
4. The display flashes HOLD as the oven enters
HOLD mode. This is also considered second
stage cooking (oven heating stops but product
continues to cook on residual heat).
A. Convection fan motor is de-energized.
5. After the oven temperature drops below 150°F,
the heat comes back ON and cycles as needed,
to maintain the "Hold" temperature of 150°F.
A. Convection fan motor energized (Low
speed).
6. The oven continues to cycle in this manner until
one of the following occurs:
A. The "Roast & Hold" mode is turned OFF.
B. Power switch (S1) is turned to the OFF or
COOL DOWN position.
Cool Down Cycle
1. Conditions.
A. Oven is ON.
B. Oven cavity temperature needs to be
lowered.
C. Doors are open (door switch contacts
OPEN).
D. Power switch (S1) set to either ON or OFF.
2. Power Switch (S1) turned to COOL DOWN.
A. Power is connected through power switch
(S1) to the convection fan motor high speed
terminal.
Page 41 of 64
Power is removed from convection fan
motor high speed terminal.
Power is applied to the convection fan
motor low speed terminal.
F25105 Rev. B (0217)