SG4D Vulcan convection oven I thought the door switch was broken , when I connected the two wires that ran to the switch the oven fired up it got hot the fan ran all seemed well . won't work now why?

SOURCE: Vulcan SG4D convection oven is shutting off.

http://www.vulcanhart.com/manuals/F-35626.pdf
Since you were lacking a few specifics, go to this web site and it will have the service manual on your unit.
Hope this helps

John Rodgers

• 80 Answers
• Posted on Feb 05, 2010

SOURCE: vulcan convection oven sg4d-1 no power to gas valve,ignitor

ensure area around ignitor is prefectly clean

Treefrog15

• 130 Answers
• Posted on Feb 25, 2010

SOURCE: vulcan convection oven model SG4d-1 will not

Gas does not ignite. No spark. No Ignition light is not ON.
1. Shorted electrode on igniter/flame sense.
2. Igniter cable (high voltage) OPEN.
3. Heat relay malfunction.
4. Centrifugal switch in blower motor inoperative.
5. Transformer inoperative.
6. High limit thermostat open.
7. Interconnecting wiring malfunction.
8. Ignition module malfunction.

Sparks but gas does not ignite.

1. Gas solenoid valve off or inoperative.
2. Manual gas valve closed.
3. Gas supply OFF or insufficient gas pressure.
4. Inerconnecting wiring malfunction.
5. Igniton module malfunction.