Repair manual

MT1828
2 --- 3
SEQUENCE OF OPERATION
MT1828G DOMESTIC AND GENERAL EXPORT OVENS INTERNAL MOUNT --- M7296
REV B
COMPONENT REFERENCE
NOTE: Refer to FIGURE 2 for component loca-
tions.
1. BLOWER RELAY
2. BELT STOP RELAY
3. HEAT RELAY
4. MOTOR CONTACTOR
5. SINGLE POLE DOUBLE THROW THERMAL
SWITCH
6. MOTOR CONTROL BOARD
7. SINGLE POLE SINGLE THROW THERMAL
SWITCH
8. RESETABLE HI LIMIT
9. 115/24 VOLT TRANSFORMER
10. FLAME BLOWER
11. IGNITION CONTROL MODULE
12. COOKING COMPUTER
13. PRESSURE SWITCH
14. H.S.I.
15. BU RNER VALVE
16. PROOF OF FLAME ROD
17. SINGLE POLE DOUBLE THROW THERMAL
SWITCH
18. CONVECTION BLOWERS
19. COOLING FANS
OPERATION
1. Apply power to the oven. Program time and
temperature into the computer (12). The blow-
er relay (1), belt stop relay (2) and heat relay (3)
close.
2. When the blower relay (1) closes, 110 V.A.C.
are sent to the coil of the motor contactor (4)
starting the convection blowers (18) and N.C.
terminal of a single pole double throw thermal
switch (5).
3. When the belt stop relay (2) closes, 110 V.A.C.
are sent to t he motor control board (6) and the
single pole single throw thermal switch (7). If
this switch is closed, power goes to the reset-
able hi limit switch (8).
4. If the resetable hi limit switch is closed power
goes to the 115/24 volt transformer (9) located
in the box mounted on the flame blower (10).
The flame blower starts.
5. The secondary side of the transformer (9)
sends 24 volts to L1 of the ignition control mod-
ule (11) and one side of the heat relay (3). If the
computer (12) closes the heat relay, the 24
voltswillgotothepressureswitch(13).
6. If the pressure switch is closed, a circuit will be
completed back to the ignition module (11).
7. The ignition module initiates its firing sequence
by sending power to the H.S. I. (14). After a
warm up period both solenoids on the burner
valve (15) open allowing gas to enter for igni-
tion. If no flame is sensed by the proof of flame
rod (16) the system shuts down.
NOTE: Some ignition control modules may try
to refire up to 3 times. However, there
will be a longer warm up period be-
tween each attempt at ignition.
8. The thermal switches (5 and 17) toggle from
common to N.O. only when they reach the tem -
perature stated on the back of the switch.
9. The convection blowers (18) receive their pow-
er from the motor contactor (4) only.
10. The cooling fans (19) come on only when the
motor contactor (4) is energized or if the ther-
mal s witches (5 and 17) have toggled.