Sequence Of Operations; Sg4D/Sg6D With Solid State Temperature Controller; Cook Cycle - Vulcan-Hart SG4D ML-114875 Service Manual

SEQUENCE OF OPERATIONS

SG4D/SG6D with Solid State Temperature
Controller
Schematic 424373-1 will be used to explain the
electrical sequence of operation.

Cook Cycle

1. Conditions
A. Oven connected to correct voltage.
1) L1 (HOT) to power switch (S1).
2) L2 (neutral or second line) to one
side of the following components: L1
of the power level control, power ON
light, heat light, temperature controller
board terminal 9 (120VAC) or terminal
10 (208-240 VAC), oven cavity lights,
buzzer, timer motor, heat relay coil
(R3), convection fan motor common
(C), transformer primary T1), motor
speed (Hi/Low) relay coil (R1), hold
relay coil (R2) and the component
cooling fan.
B. Oven properly grounded.
C. Gas supply valve ON.
D. Gas combination control valve ON.
E. Power switch (S1) OFF.
F. Oven light switch (S2) ON/OFF (position
has no affect on the function of the
normal cooking cycle).
G. Temperature controller dial set to lowest
temperature (fully counterclockwise).
H. High limit switch closed (position has no
affect on the function of the normal
cooking cycle).
I. Timer in the OFF position.
J. Oven doors closed.
K. Door switch contacts closed.
L. Oven cavity temperature below 140°F.
M. Power level switch to 100%.
2. Set temperature controller dial to desired
temperature.
A. Contacts 6 and 7 close.
3. Power switch (S1) is turned ON.
NOTE: Power is available to the oven light switch
A. Component cooling fan energized.
B. ON light (amber) is lit.
C. Power to timer terminal C.
D. Transformer (T1) energized.
1) Power (24 VAC) to one side of the
following components: heat relay (R3)
normally open (N.O.) contact.
2) First valve (safety) on the gas valve
energized. Gas does not flow to the
burner until the 2nd valve (main) is
energized.
3) Ignition module energized.
E. Heating light is lit.
F. Power level control energized.
1) Power level light lit.
2) Power to one side of centrifugal
switch.
G. Convection fan motor is energized through
(S3) high-low.
1) When the convection fan motor
reaches operating speed, the
centrifugal switch (N.O.) on the motor
closes.
H. Heat relay is energized.
1) N.O. contacts close.
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