Repair manual
MT1828
2 --- 1 1
MT1828E CE OVENS --- M6453 REV A
COMPONENT REFERENCE
NOTE: Refer to FIGURE 6 for component loca-
tions.
1. COOKING COMPUTER
2. BLOWER RELAY
3. BELT STOP RELAY
4. HEAT RELAY
5. 240/120 STE P DOWN TRANSFORMER
6. MOTOR CONTACTOR
7. SINGLE POLE DOUBLE THROW THERMAL
SWITCHES
8. COOLING F ANS
9. SPEED CONTROL BOARD
10. D.C. DRIVE MOTOR
11. SINGLE POLE SINGLE THROW THERMAL
SWITCH
12. RESETABLE HI LIMIT
13. ELEMENT CONTACTOR
14. ELEMENTS
15. CONVECTION MOTORS
OPERATION
1. Apply power to the oven. Program the time and
temperature into the computer (1). The blower
relay (2), belt stop relay (3) and heat relay (4)
are energized.
2. Voltage is applied to the contacts of these re-
lays by a 240/120 volt step down t r ansformer
(5).
3. If the blower relay (2) is closed voltage is ap-
plied to the coil of the motor contactor (6). The
contactor is energized and voltage is supplied
to the normally closed terminals of the single
pole double throw thermal switch (7).
4. If both of these switches are closed between C
and N.C. All five cooling fans start. The
switches toggle from C and N.C. to C. and N.O.
when the temperature of the air passing them
exceeds the rating on the back of t he switches.
5. If the belt stop relay (3) is closed, power goes
to the speed control board (9). The board
sends D.C. voltage to the D.C. drive motor (10).
The voltage output varies with the time pro-
grammed into the computer (1).
6. If the heat relay (4) is closed, power goes to a
single pole single throw thermal switch (11). If
this switch is closed, power goes to a manual
resetable hi limit (12). If this switch is closed,
power goes to the coil of the hot air element
contactor (13). The element is energized and
power is sent t o the heating elements (14).
7. The thermal switches (7 and 11) react to ambi-
ent a ir moving across the face of the switch.
They react only when the temperature ex-
ceeds the rating on the back of the switch. The
single pole double throw thermal switch (7)
toggles when the temperature rises. The
single pole single throw thermal switch (11)
opens when the temperature rises.
8. The manual hi limit (12) opens when the tem-
perature inside the oven cavity exceeds 690_F
(366_C).
9. The convection motors (15) are powered when
the motor contactor (6) is energized.