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SECTION 3
OPERATION
II. COMPONENT INFORMATION AND LOCATION
Door Safety
Switch
Conveyor
Speed
Control
Blower
Fan Motor
Figure 3-2
A. Door Safety Switch
The Door Safety Switch is located at upper left hand side
of control cabinet. Opening the control cabinet door will
permit the switch to open, disconnecting power to all
electrical controls.
CAUTION: DO NOT TOUCH WIRES GOING TO THIS
SWITCH AS CURRENT IS ALWAYS PRESENT.
B. Blower Fan
The blower switch located on the control box has
two positions. The switch must be on (I) for the burner and
conveyor to come on and permit the oven to warm up.
The fan circulates the air throughout the oven and must
stay on during baking and during the cool down cycle
above 200° F. (93°C.) to prevent blower bearing dam-
age. To protect the blower motor and bearings a thermo-
static override is built into the oven. If the temperature
inside the oven is over 180° F. (82° C.) the main blower
and conveyor will continue to run even when the blower
switch is turned to the off position.
An air pressure switch monitors the air flow from the main
blower, this acts as a safety interlock for the burner. The
heat will not come on if the air switch does not sense air
flow off the main blower fan.
C. Heat (Gas ovens only)
Turning the heat switch to on (I) will initially set up the
oven purge circuit after approximately 30 seconds the
pilot will light. After the pilot is lit the main control valve will
open permitting gas to go to the burner and heat the oven.
This switch is in series with the burner blower motor
centrifugal switch, high temperature safety switch and
blower fan air pressure switch. All three safety switches
must be closed for gas to flow and the burner to light.
D. Temperature Controller
The temperature controller located on the control box
is a solid state on/off type which is used to maintain the
desired set temperature. The temperature controller
continuously monitors the oven temperature and turns
high flame solenoid valve on in gas heated ovens. The
heat is on for the time required to maintain a constant
temperature.
The temperature controller contains a Hi-Limit switch
which will shut down the oven when the oven reaches
650°F. (343° C.) and a low-limit switch which allows the
oven to cool down to 180°F. (82° C.) before shutting off
the blowers.
E. Heat (Electrically heated ovens only)
Turning the heat switch located on the control box
to on (I) will energize the electric heating system. This
switch is in series with the blower fan motor centrifugal
switch and high temperature override switch. Both
switches must be closed before the elements may be
energized.