Power Supply

SEQUENCE OF OPERATIONS

(For serial numbers before 2038616 w/ analog control)

MODEL 1154-000-EA	NAT. GAS	230 VAC	50 HZ.	1 PHASE
MODEL 1155-000-EA	LP GAS	230 VAC	50 HZ.	1 PHASE

Electrical power to be supplied to the oven by a three conductor service.

CONTROL BOX AUTO COOL DOWN

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° (37.8°C, ± 1.7°C).

MAIN FAN CIRCUIT

Power is permanently supplied through the 10A oven fuse, through the normally closed control box hi-limit thermostat (opens at 140° F, 60° C) to the normally open double pole oven fan switch and to the cooling fan. Closing the oven fan switch supplies line voltage to the main fan motor. Closing the fan switch also supplies voltage to the cooling fan. The conveyor, burner and temperature display are also energized.

BURNER CIRCUIT

Closing the oven fan switch supplies line voltage through the normally open gas pressure switch (located in the gas valve and closed when gas pressure is present), through the normally open air pressure switch (closed by air pressure from the main fan), through the normally closed oven cavity hi-limit thermostat (opens at 662° F, 350°C which is manually resettable after a drop in temperature of 18° F, 10° C), and to the ignition control.

IGNITION CONTROL

The ignition control switches line voltage to the combustion blower motor, the combustion air switch switches from normally closed to normally open upon sensing air pressure in the burner housing. After a pre-purge period of between 30 and 60 seconds, the spark generator is energized, the main gas valve and the burner pilot light are energized, and ignition should now occur.

TEMPERATURE CONTROL

Closing the oven fan switch supplies line voltage to the temperature control. The 1K ohm temperature pot. is adjusted to desired temperature. The thermocouple will provide varying millivolts to the temperature control. The temperature control supplies line voltage to the temperature regulation valve at intermittent intervals to maintain desired temperature. The heat lamp is energized with the temperature regulation valve.

CONVEYOR DRIVE

Closing the oven fan switch supplies line voltage to the motor 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 and 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 increase 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.

TEMPERATURE DISPLAY

Closing the switch supplies line voltage to primary of the temperature display transformer. The secondary of this transformer supplies 12VAC to the temperature display. The thermocouple supplies DC millivolts to the temperature display. The display converts this millivolt reading to a temperature reading.

2	Impinger II – 1100-000-A Series (SN 2038615 & Below) Service Manual –Int’l