Blodgett MT2136 Series, Service And Repair Manual

Page: 47 / 94

MT2136
3-23
MT2136G GENERAL EXPORT - M7295 REV B
COMPONENT REFERENCE
NOTE: Refer to FIGURE 13 page 3-34 for compoĆ
nent locations.
1. COOKING COMPUTER (M7880)
2. BLOWER RELAY (22672)
3. BELT STOP RELAY (22672)
4. HEAT RELAY (22672)
5. MOTOR CONTACTOR (M2247)
6. CONVECTION FANS (CCW) (M2872)
7. CONVECTION FANS (CW) (M2873)
8. DC DRIVE BOARD (M3153)
9. SINGLE POLE SINGLE THROW THERMAL
SWITCH (M1362)
10. DC MOTOR (M3128)
11. MANUAL RESET HI LIMIT SWITCH (M3295)
12. TRANSFORMER (M2381)
13. FLAME BLOWER (M2386)
14. CENTRIFUGAL SWITCH
15. IGNITION CONTROL MODULE (M1054)
16. PILOT VALVE
(Natural - M5495, LP - 22190)
17. MAIN BURNER VALVE
(Natural - M5495, LP - 22190)
18. RTD PROBE (M7427)
19. STEP DOWN TRANSFORMER (M7170)
20. HALL EFFECT PICKUP (M0984)
21. COOLING FANS (23034)
22. SINGLE POLE DOUBLE THROW THERMAL
SWITCH (M2453)
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)
pull in and power up three separate circuits.
The voltage to the relay coils is 12 VDC.
2. The blower relay (2) closes sending 115VAC to the
coil of the motor contactor (5). Points 1, 2, 3 and
4 close powering the convection fans (6 & 7).
NOTE: 115 volts is applied to one side of the
relays from a 240Ć120 volt step down
transformer (19).
3. The belt stop relay (3) sends 115VAC to the DC
drive board (8) and one side of a single pole
single thermal switch (9). The DC motor (10)
starts provided there is a time entered in the
cooking computer (1).
NOTE: The thermal switch is located in the
rear of the blower compartment. This
switch opens when the face of the
switch sees 140 5 F and closes when
there is a 10Ć20 5 drop in temperature
across the face of the switch. The
switch interrupts the heat circuit.
NOTE: 115 volts is applied to one side of the
relays from a 240Ć120 volt step down
transformer (19).
NOTE: The motor used in this oven is 180 volts
DC at its highest speed.
NOTE: This relay will only be powered if there
is a time programmed into the computĆ
er. THE OVEN WILL NOT HEAT IF TIME
IS NOT PROGRAMMED INTO THE
COMPUTER.
4. If the thermal switch is closed, power goes to
one terminal of the manual reset hi limit switch
(11). If the hi limit switch is closed, power is
supplied to the primary side of the transformer
(12) and the flame blower (13).
5. When the combustion motor reaches full
speed, a centrifugal switch (14) closes sendĆ
ing 24 VAC to the ignition module (15). After
the module's self diagnostics are complete,
the pilot valve (16) opens. When a proof of
flame is established the main burner valve (17)
is allowed to open.