Vulcan-Hart VC4G Service Manual page 47

VC4G & VC6G SERIES FULL SIZE CONVECTION OVENS - ELECTRICAL OPERATION
4. Oven reaches set temperature and controlling
thermostat opens.
A. Heat light goes out.
B. Power removed from heat relay (R3).
1) R3 normally open (N.O.) contacts
open.
a. Ignition control module de-
energize.
a)
NOTE: This is considered first stage cooking in the
ROAST AND HOLD cycle.
5. The oven will continue to cycle on the controlling
thermostat until one of the following occurs:
ROAST & HOLD time (R & H cooking) expires
which allows the oven to go into Hold mode;
Power switch (S1) is turned to the OFF or COOL
DOWN position or the doors are opened.
Timer Cycle (Roast & Hold Cooking))
NOTE: The ROAST & HOLD timer operates
independently of the heating cycle until time expires.
Regulation of the oven temperature is then transferred
to the Hold thermostat until one of the following
occurs: ROAST & HOLD timer is turned OFF and the
function switch (S3) is turned back to Normal ROAST
(normal cooking) or power switch (S1) is turned to the
OFF or COOL DOWN position.
1. With the power switch turned ON, power is
supplied to timer.
2. Set ROAST & HOLD timer to desired time (Roast
& Hold cooking).
If a flame is not
"sensed" after 7
seconds of sparking,
the "no ignition" light
comes back on, 2nd
valve (main) on the gas
valve is de-energize
and gas flow to the
burner stops. Ignition
trial cycle repeats after
a 15 second purge
between cycles for two
additional tries before
locking out. To reset
after a lockout, turn
power switch (S1) OFF
then ON.
Power removed from 2nd
valve (main) on the gas valve
and gas flow to the burner
stops.
NOTE: To Roast then Hold the cooked product at a
fixed temperature, the Roast & Hold timer must be
used and the function switch (S3) must also be set to
Roast & Hold as indicated under step1 conditions for
the Roast & Hold cycle.
A. Contacts 1 & 3 close, timer motor is
energized and timing "down" begins.
3. Time expires on Roast & Hold timer.
A. Contacts 1 & 3 open, timer motor is de-
energize and timing stops.
B. Contacts 1 & 4 close.
1)
2)
NOTE: When temperature is above 160°F (±12) the
hold thermostat contacts are open.
3)
NOTE: This is considered second stage cooking in
the ROAST AND HOLD cycle where the stored heat
in the oven continues to cook the product.
4. Oven temperature falls below 160°F (±12) and
hold thermostat contacts close.
A. Heat light comes ON.
B. Motor speed relay (R1) is energized through
one set of R4 (N.C.) contacts.
1)
C. Power is applied to one side of the
centrifugal switch on the convection fan
motor through the other set of R4 (N.C.)
contacts.
D. When the convection fan motor reaches
operating speed, the centrifugal switch on
the motor closes.
1)
Page 47 of 75
If the oven was heating, then the gas
burner and heat light go out; If the oven
was not heating, then the gas burner
and heat light remain out.
Hold relay (R2) is energized, R2
contacts change state and the normally
open (N.O.) contacts close.
a. Power to one side of hold
thermostat.
Relay R4 is energized, R4 contacts
change state and both sets of normally
closed (N.C.) contacts transfer to the
normally open (N.O.) position. Power is
not transferred until the hold
thermostat contacts close.
Convection fan motor energized (fan
speed low).
Heat relay (R3) is energized.
F24682 Rev. D (1016)