Repair manual
OPERATION
3-12
NOTE: The switch is located in the front conĆ
trol compartment. It protects the other
components from hi ambient heat.
If this switch is cold, it should be closed sendĆ
ing power to the single solenoid gas valve (17).
4. When power is applied to the coils of both moĆ
tor contactors (3) the contacts close sending
power to the four convection fans (6) located
in the back of the oven.
5. The oven has six cooling fans (18). Two on the
front control panel keep the panel below 140F
(60C). The fan's airflow is from left to right for
flow through ventilation. The other four, in the
rear of the oven, keep the convection fans from
overheating. The cooling fans start when the
SPST thermal switch (19) closes. The switch
toggles if the temperature passing its face exĆ
ceeds the rating on the back of the switch.
NOTE: The switch is located on the ceiling of
the convection fan compartment.
6. The conveyor is driven by an open loop D.C.
control system consisting of a conveyor switch
(20), time display (21), 10kW potentiometer
(22), D.C. speed control board (23), 130 VDC
motor (24) and #10 Hall effect pickup (25). ReĆ
fer to page 5-1 for pickup troubleshooting. AfĆ
ter the conveyor switch is turned on, the time
display illuminates. The D.C. control board
powers up. The output voltage measured at A1
and A2 of the board to the motor varies from 20
to130 VDC based on the position of the potenĆ
tiometer. The speed of the motor should also
vary. The time display varies depending on the
speed of the Hall effect pickup. The pickup
sends an R.P.M value to the display. The disĆ
play converts this value to minutes:seconds.
NOTE: This type of system does not sense the
weight of the product and will slow
down slightly if the belt is fully loaded.