FULL SIZE GAS CONVECTION OVENS - ELECTRICAL OPERATION
SEQUENCE OF OPERATION
WKG, WKGX With Roast & Hold Option
(Mechanical KX Thermostat)
Schematic diagram 10832 will be used to explain the electrical sequence of operation for both the Normal ROAST cycle (normal cooking) and the ROAST & HOLD cycle.
Normal Roast 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: power ON light, heat light, oven cavity lights, buzzer, ROAST timer motor (normal cooking), ROAST & HOLD timer motor, heat relay coil (R3), convection fan motor common (C), transformer primary (T1), relay coil (R4), 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.Function switch (S3) set to Normal ROAST cycle.
G.Oven light switch (S2) ON/OFF (position has no affect on the function of the Normal ROAST cycle).
H.Control thermostat dial 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 thermostat to desired Normal ROAST temperature (normal cooking).
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.
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C.Power ON light (Amber) comes ON.
D.Power to one side of the following components: Normal ROAST timer terminal 1, ROAST & 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
a)1st valve (safety) on the gas valve energized.
NOTE: Gas does not flow to the burner until the 2nd valve (main) is energized.
2)With door switch closed, power is connected back 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.
3)Power is also connected through the other 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)Power is connected through the function switch (S3) contacts and the convection fan motor is energized (fan speed Hi).
F32700 (February 2006)
