Vulcan-Hart VC4G Service Manual page 46

VC4G & VC6G SERIES FULL SIZE CONVECTION OVENS - ELECTRICAL OPERATION
H. Control thermostat in the OFF position
(OPEN).
I. High limit switch CLOSED.
J. Roast timer (normal cooking) in the OFF
position..
K. Roast and Hold timer in the OFF position.
L. Oven doors Closed.
1) Door switch contacts CLOSED.
M. Oven cavity temperature below 140°F.
2. Set controlling thermostat to desired ROAST
then Hold temperature (Roast & Hold cooking).
NOTE: This is considered first stage cooking in the
ROAST & HOLD cycle.
A. Internal contacts close.
3. Power switch (S1) turned ON.
A. Power to motor speed (Hi/Low) relay (R1)
normally open (N.O.) contacts and hold
relay (R2) common (C).
B. Component cooling fan energized.
C. Power ON light (Amber) comes ON.
D. Power to one side of the following
components: "Cook" timer terminal 1, "Cook
& Hold" timer terminal 1, transformer
primary (T1).
NOTE: Power is available to the oven light switch
(wire #20) to turn the oven cavity lights ON when the
light switch is turned ON; and power is available to the
normally open N.O. side (wire #28) of the door switch
contacts and connects power to additional
components when the door switch contacts are
CLOSED (door closed).
1) Transformer (T1) energized.
a. Power (24VAC) to one side of the
following components: heat relay
(R3) normally open (N.O.)
contacts, high limit—connected
through the normally closed
(N.C.) contacts to the 1st valve
(safety) on the dual solenoid gas
valve.
a)
NOTE: 1st valve (safety) on the gas valve energized.
F24682 Rev. D (1016)
1st valve (safety) on the gas
valve energized.
2)
3)
NOTE: In the ROAST & HOLD cycle, the fan speed
is fixed at low.
Page 46 of 75
With door switch closed, power is
connected through a second set of
contacts on the power switch (S1),
through the thermostat contacts,
through one set of relay R4 normally
closed (N.C.) contacts, to one side of
the centrifugal switch on the
convection fan motor.
a. Heat light (clear) comes ON
Power is also connected through the
another set of relay R4 normally closed
(N.C.) contacts to the other side of
motor speed relay (R1).
a. Motor speed relay (R1)
energized, contacts change state
and the normally open (N.O.) set
of contacts close.
a) Convection fan motor
energized (fan speed low).
b) When the convection fan
motor reaches operating
speed, the centrifugal switch
on the motor closes. The
heat relay (R3) is then
energized, R3 relay contacts
normally open (N.O.) close
and the heating circuit is
powered.
1. Ignition control module
is energized.
2. No ignition light (red)
comes ON, module
performs a self
diagnostic test for 4
seconds, 2nd valve
(main) on the gas valve
is energized. Gas starts
to flow to the burner,
sparking begins, the "no
ignition" light goes out
and burner lights.
Sparking continues for
up to 7 seconds or until
a flame is established. If
a flame is "sensed", the
"no ignition" light stays
out and burner remains
lit.