Lang GCCO-T Service Manual page 34

Power switch turned to "ON" position.
Power to oven light switch .
120/24-volt transformer energized.
24 volts to TH, and ground of spark module.
Spark module begins sparking at pilot burner.
24 volts to pilot valve coil of combination gas valve.
Pilot valve opens.
Gas flows to pilot burner.
Pilot burner lights.
Pilot light confirmed by spark module.
12 to 13 micro amps on pin 4 (Johnson Control), and Sens (Channel products).
24 volts from pin 3 (Johnson Control) and MV (Channel products) to isolation transformer.
24-volt isolation transformer energizes.
24 volts to pins 1 and 2 of circuit board.
24 volts at motor out put (pin5) to ground.
24 volts to motor relay through door switch and pulse-fan switch.
Motor relay closes energizing motor and closing centrifugal switch.
Temperature set on circuit board.
24 volts at heat out put to ground.
24 volts from circuit board to MV on combination valve through pulse-switch, centrifugal switch,
and over temperature thermostat.
Main burner ignites.
SEQUENCE OF OPERATION GCCO-SII
34