Vulcan-Hart SG4D service manual

Page 36

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.

– 36 –

Page 35 Page 37
Image 36
Page 35 Page 37
Contents SG4 & SG6 Series Full Size GAS Convection Ovens VULCAN-HART Table of Contents Table of Contents General Removal and Replacement of Parts Component LocationCovers and Panels Top Front CoverBottom Front Cover Right Side PanelControl Panel Components SG4D/SG6D SG4C/SG6CComponent Panel Components Temperature Probe SG4C/SG6C Temperature Probe ShownGAS Burners GAS Orifice GAS Solenoid ValveIgnition Control Module Spark Igniter and Flame SenseBlower and Motor Oven Doors and Bearings Roller Latch Assembly Independent Doors Door Catch Roller Assembly Independent DoorsDoor Window Door Switch Lamp Assembly High Limit ThermostatInterior Lights Fan Installation Tips Cooling FANService Procedures and Adjustments Solid State Temperature Controller Test SG4D/SG6DTest Steps Solid State Temperature Control Calibration SG4D/SG6D Calibration StepsTemperature Probe Test SG4D/SG6D Temp F OhmsOperation Setup Mode Computer Controller SG4C/SG6CProbe Test Computer Control Calibration SG4C/SG6C Solid State Relay TestGAS Pressure Adjustment Door Switch Adjustment Verification of Spark AT IgnitorBlower Adjustment Flame Current MeasurementDoor Adjustment Door Strike Adjustment Independent DoorsDoor Catch Roller Adjustment Electrical Operation Component DescriptionFront View Plug, Socket and Components SG4D/SG6DControl Panel Component Panel Front ViewPlug, Socket and Components SG4C/SG6C SG4D/SG6D with Solid State Temperature Controller Sequence of OperationsCook Cycle Timer Cycle Cool Down Cycle Solid State Temperature ControllerSG4C/SG6C with Computer Controller Normal Cook CyclePage Temperature and Time Cycle Normal Cooking Roast and Hold CycleWiring Diagrams 426574 Rev. C Schematics ThermostatGAS Convection Oven SG4 with Watlow 734 Control Troubleshooting Symptoms Possible CausesComputer Control Models only Symptom Possible Causes Symptoms Possible CausesError Codes Probable Cause Solution Problem
Top Page Image Contents