Impinger II – 1100-000-A Series (SN 2038615 & Below) Service Manual –Int’l 3
POWER SUPPLY
Electrical power to be supplied to the oven by a four conductor service.
Brown conductor is Hot.
Black conductor is Hot.
Black conductor is Hot.
Green conductor is ground.
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 ther mostat 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 normally closed oven cavity hi-limit, through the 10A f use, through the
normally closed control box hi-limit thermostat, to the normally open main fan switch. Power is a lso supplied to the
normally open cooling fan thermostat. Closing the main fan switch supplies 230 VAC to the m ain fan motor, the
cooling fan motor, to the primary of the temperature display transformer and to the heat and con veyor circuits.
HEAT CIRCUIT
Closing the oven fan switch supplies 230VAC, through the normally open air pressure switch (c losed by air
pressure from the main fan) to the electronic temperature control. The 1K ohm temperature pote ntiometer is
adjusted to desired temperature. The thermocouple will provide varying millivolts to the tem perature control. The
temperature control then supplies 230 VAC to the coil of the contactor at intermittent intervals to m aintain the
desired temperature. The heat lamp is energized with the contactor.
CONVEYOR DRIVE
Closing the oven fan switch supplies 230 VAC through the EMI filter to the motor control board. AC volts are
converted to DC volts and are supplied to the conveyor motor at terminals A+ and A-. Adjustm ent of the speed
control potentiometer will change resistance at terminals P1 and P2 varying the DC voltage to t he 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 s enses the motor
speed. Any change in motor load (± RPM) is detected by the sensor and the voltage to the m otor is adjusted
accordingly.
TEMPERATURE DISPLAY
Closing the main fan switch supplies 230 VAC to the primary of the temperature display transf ormer. The
secondary of this transformer supplies 12 VAC to the temperature display. The thermocouple supp lies DC
millivolts to the temperature display. The display converts this millivolt reading to a temper ature reading.