Vulcan-Hart VC4G Service Manual page 53

VC4G & VC6G SERIES FULL SIZE CONVECTION OVENS - ELECTRICAL OPERATION
B. Power removed from heat relay (R3) and
the contacts open (N.O.).
1) Ignition control module de-energized.
a. Power removed from 2nd valve
(main) on the gas valve and gas
flow to the burner stops.
C. Power is also removed from motor speed
relay (R1).
1) Convection fan motor de-energized
and fan stops rotating.
6. The oven will continue to cycle on the hold
thermostat until the ROAST & HOLD timer is
turned to the OFF position and the function
switch (S3) is change back to ROAST (normal
cooking) or the power switch (S1) is turned to the
OFF or COOL DOWN position.
Cool Down Cycle (Solid State Temperature
Control)
NOTE: The electrical sequence of operation for the
COOL DOWN cycle is written for ovens with the
ROAST & HOLD option.
1. Conditions.
A. Oven is ON.
B. Oven cavity temperature needs to be
lowered.
C. Doors are open.
1) Door switch contacts OPEN
D. Cook and Hold timer in the OFF position.
E. Cook timer (normal cooking) in the OFF
position.
F. Function switch (S3) set to either Normal
ROAST cycle or ROAST & HOLD cycle.
2. Power Switch (S1) turned to COOL DOWN.
NOTE: With door switch contacts OPEN (doors
open), the convection fan motor will still run and
continue to cool the oven. However, power would be
removed from the following components: Power ON
light (goes out), Normal ROAST timer, ROAST &
HOLD timer, transformer T1 (de-energized) and to the
component cooling fan.
A. Power to motor speed (Hi/Low) relay (R1)
normally open (N.O.) contacts and to
common (C) on hold relay (R2). Power is
then connected through hold relay (R2)
normally closed (N.C.) contacts to motor
speed (Hi/Low) relay (R1) coil.
1) Motor speed (Hi/Low) relay (R1) is
energized and contacts change state.
NOTE: If function switch (S3) is set to Normal ROAST
cycle, fan speed will be high; if set to ROAST & HOLD
cycle, fan speed will be low.
B. Power to one side of the hold thermostat
contacts but is not transferred to other
components due to oven cavity temperature
above 160°F (thermostat OPEN).
C. Power to terminal 7 on the solid state
temperature control but is not transferred to
other components due to temperature
control not being powered.
3. If door switch is CLOSED (doors closed), power
is supplied to one side of the following
components: Power ON light (Amber), oven light
switch (S2), Normal ROAST timer terminal 1,
ROAST & HOLD timer terminal 1, transformer
primary (T1) and component cooling fan.
A. Power ON light (Amber) comes ON.
B. Transformer (T1) energized.
1)
NOTE: Gas does not flow to the burner until the 2nd
valve (main) is energized.
C. Component cooling fan.
4. The oven will remain in this condition until the
power switch (S1) is turned to the OFF or ON
position.
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a. Power is connected through
motor speed (Hi/Low) relay
normally open (N.O.) contacts,
through function switch (S3) to
Convection fan motor.
a) Convection fan motor
energized.
b) When Convection fan motor
reaches operating speed the
centrifugal switch on the
motor closes but no power is
available for connection to
other components.
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. 1st valve (safety) on the gas valve
energized.
F24682 Rev. D (1016)