Sequence Of Operations; Model 1456 / 220-240 Vac / 50 Hz / Natural Gas; Model 1457 / 220-240 Vac / 50 Hz / L.p. Gas; Model 1474 / 220-240 Vac / 50 Hz / Natural Gas - Lincoln 1400 Series Service Manual

POWER SUPPLY
CONTROL BOX AUTO
COOL DOWN
MAIN FAN CIRCUIT
BURNER CIRCUIT
TEMPERATURE
CONTROL
CONVEYOR DRIVE
Impinger I – 1400 Series Advantage Service Manual – Dom & Int'l

SEQUENCE OF OPERATIONS

MODEL 1456 / 220-240 VAC / 50 HZ / NATURAL GAS

MODEL 1457 / 220-240 VAC / 50 HZ / L.P. GAS

MODEL 1474 / 220-240 VAC / 50 HZ / NATURAL GAS

MODEL 1475 / 220-240 VAC / 50 HZ / L.P. GAS

MODEL 1476 / 220-240 VAC / 50 HZ / TOWN GAS

Electrical power is to be supplied to the oven by a three-conductor service.
Brown conductor is hot.
Blue conductor is neutral.
Green conductor is ground.
When the temperature in the control box reaches 120°F ± 3° (48.9°C ± 1.7°C), the cooling
fan thermostat will switch power to the control box cooling fan. The thermostat will interrupt
power to the cooling fan when the control box temperature falls to 100°F ± 3° (37.0°C ±
1.7° C).
Electrical power is permanently supplied to the normally open contacts of the double pole
main fan relay, the cooling fan thermostat and, through a 3A fuse to the normally open
double pole main fan switch. Closing the oven fan switch supplies line voltage to the
primary of the control circuit step down transformer. The transformer steps the voltage
down to 120 VAC for the control circuit. 120 VAC is supplied to the coil of the double pole
main fan relay. The coil of the relay is energized. The normally open contacts now close,
energizing the main fan motor through one 10A fuse, and the cooling fan motor.
Closing the oven fan switch supplies line voltage through the main fan air pressure switch,
through the gas pressure proving switch, through the normally closed Hi-Limit Thermostat,
to the ignition control. The combustion motor is now energized The normally open
combustion air switch closes upon sensing air. After a pre-purge period of between 30 and
60 seconds, the spark generator and the main gas valve are energized. Ignition should
now occur, after proving, gas control relay is energized.
Closing the oven power switch supplies 120 VAC (through the step-down transformer) to
the temperature control board. The temperature dial is adjusted to desires temperature.
The thermocouple will provide varying millivolts to the temperature controller. The
temperature controller supplies120 VAC through contact of gas control relay to the
solenoid valve at intervals to maintain desired temperature. The ready lamp is energized
with the solenoid valve (an electronic flame monitor proves main flame operation in the
1474, 1475, 1476 models.)
Closing the on/off switch supplies 120 VAC (through the step down transformer) to the
conveyor control board. AC volts are converted to DC volts and are supplied to the
conveyor motor at terminals A+ and A-. Adjustment of the speed control potentiometer will
change resistance at terminals P1 & P2 varying the DC voltage to the motor. The speed of
the conveyor motor will increase or decrease as the DC voltage from the board increases
or decreases respectively.
NOTE: The conveyor control uses a sensor and magnet, mounted on the conveyor motor
that senses the motor speed. Any change in motor load (± RPM) is detected by the sensor
and the voltage to the motor is adjusted accordingly.
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