Vulcan-Hart SG4D service manual

C.Power to terminal 1 on solid state relay 1 SSR1-load side and solid state relay 2 SSR2-load side.

D.Component cooling fan energized.

E.Transformer (T1) is energized, 24 volt output.

1)Power (24 VAC) to one side of the following components: heat relay (R1) normally open (N.O.) contacts, high limit connected through the normally closed (N.C.) contacts to the first valve (safety) on the dual solenoid gas valve.

2)First valve (safety) on the gas valve energized. Gas does not flow to the burner until the second valve (main) is energized.

3)Ignition module energized.

4)Power (24 VAC) to the oven computer control.

3.Control is energized and performs a power on self test before energizing outputs. If the control passes self test, then the outputs are energized and operation sequence continues, If control does not pass self test, then the corresponding error code is displayed.

NOTE: Control retains last temperature set.

A.Computer control senses oven cavity temperature.

1)With the oven cavity temperature below set point, the controls 120 VAC output from pin C3-2 is activated and power is connected to the common (C) side of the blower switch contacts on the convection fan motor.

2)The controls 5 VDC output from pins C2-2 (-) and C2-8 (+) is activated and SSR1 relay is energized.

a.Convection fan motor is energized (fan speed on HI).

3)When the convection fan motor reaches operating speed:

a.The blower switch (N.O.) on the motor closes.

B.Heat relay coil (R1) energized.

1)(R1) contacts (N.O.) close and the heating circuit is powered.

2)Oven heat light on the control comes on.

C.Ignition module is energized.

1)Heating circuit is powered.

2)No ignition light (red) comes ON.

3)Module performs a self-diagnostic test for 4 seconds.

4)Second valve (main) on the gas valve is energized. Gas starts to flow to burners.

5)Sparking begins, the no ignition light goes out and burners light.

NOTE: Sparking continues for up to 7 seconds or until a flame is established on both burners. If a flame is sensed on both burners, the no ignition light stays out and burner remains lit. If a flame is not sensed on both burners after 7 seconds of sparking, the no ignition light comes back on, second valve (main) on the gas valve is de-energized 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.

4.Oven reaches set point temperature.

A.Computer control deactivates the 120 VAC output to heat relay (R1).

1)Heat relay (R1) de-energized and the normally open (N.O.) contacts open.

B.Power removed from ignition control module.

1)The second valve (main) on the gas valve is de-energized and gas flow to the burner stops.

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