Repair manual

OPERATION
3-4
BLODGETT IQ - 33237 REV C
Component Reference
NOTE: Refer to FIGURE 11 page 3-11 for compoĆ
nent locations.
1. ON OFF SWITCH
2. AXIAL FAN
3. RELAY BOARD
4. TRANSFORMER
5. CONVECTION MOTOR
6. COMPUTER CONTROL
7. FOUR POLE DOUBLE THROW RELAY
Operation
1. Power is delivered to the off terminals of the on
off switch (1). When the on off switch is turned
to the on position, one leg of power will be deĆ
livered to all of the components. The other leg
of power will be interrupted by various compoĆ
nents.
2. Powered is delivered to the axial fan (2), one terĆ
minal of the heat relay, hi fan relay, and low fan
relay located on the relay board (3), primary side
of a transformer (4) and one terminal of a centrifĆ
ugal switch in the convection motor (5).
3. If the computer control (6) is programmed for
various functions such as high speed and 400
degrees F, the heat relay on the relay board will
close sending power to terminal 5 of a four pole
double throw relay (7). The convection motor
ramps up to speed, closing a centrifugal
switch, completing a circuit to the coil of the
four pole double throw relay, causing a switch
to be made between terminals 9 and 5 of the
same relay. When this switch is toggled, power
goes to the coil of a mercury contactor closing
its switches and powering up the heating eleĆ
ments.
NOTE: The four pole double throw relay also
allows for a small current to pass
through it proving to the control that the
motor is spinning. If the motor does not
spin, the centrifugal switch does not
close and the current is not able to reĆ
turn to the control. The control sees
this as a fault condition and displays a
motor error.
NOTE: The temperature probe used has an
ascending temperature coefficient.
NOTE: The cool down feature can only be actiĆ
vated by closing the door then activatĆ
ing the cool down switch. The door
can be opened after the motor reaches
speed. The door switch will also actiĆ
vate a fault condition if the door is
opened during operation.