Blodgett MT3870, Руководство по обслуживанию и ремонту

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MT3870
3-3
SEQUENCE OF OPERATION
DOMESTIC AND GENERAL EXPORT OVENS
COMPONENT REFERENCE
NOTE: Refer to FIGURE 3 for component locaĆ
tions.
1. COOKING COMPUTER
2. BURNER VALVE RELAY
3. BLOWER RELAY
4. MAIN CONTROL RELAY
5. SPEED CONTROL BOARD
6. SINGLE POLE SINGLE THROW THERMAL
SWITCH
7. MANUAL RESET HIGH LIMIT SWITCH
8. CONVECTION FAN PRESSURE SWITCH
9. TRANSFORMER
10. COMBUSTION MOTOR
11. RELAY
12. CENTRIFUGAL SWITCH
13. IGNITION CONTROL MODULE
14. PILOT VALVE
15. MAIN VALVE
16. MOTOR CONTACTOR
17. CONVECTION FANS
18. COOLING BLOWER
19. SINGLE POLE DOUBLE THROW THERMAL
SWITCH
OPERATION
1. Apply power to the oven. Program the time and
temperature into the computer (1). The burner
valve relay (2), blower relay (3) and main conĆ
trol relay (4) energize powering up the oven.
2. The main control relay (4) sends power to the
speed control board (5) and the single pole
single throw thermal switch (6). If this switch is
closed, power will be supplied to the manual
reset high limit switch (7). If this switch is
closed power flows to the convection fan presĆ
sure switch (8).
NOTE: The convection fan pressure switch (8)
will close only if the convection fans
are operating and putting a positive
pressure on the switch.
When this switch closes power goes to the priĆ
mary side of the transformer (9) located inside
of the box mounted on top of the combustion
motor (10). When the relay (11) mounted in the
same box is energized the combustion motor
(10) should start.
3. Next the centrifugal switch (12) in the motor
closes sending 24 volts to the ignition control
module (13). This powers up the pilot valve
(14). After the pilot valve is lit and the pilot flame
is established through rectification, then termiĆ
nal three of the ignition control module (13) will
send 24 volts to the burner valve relay (2). If this
relay is closed, power goes to the main valve
(15) allowing it to open and send gas into the
burner for ignition.
4. The blower relay (3) sends 115 volts to the coil
of the motor contactor (16). Once energized
the three convection fans (17) in the rear of the
oven and a cooling blower (18) located in the
combustion burner compartment start. There
is also a single pole double throw thermal
switch (19) in this circuit that allows the cooling
blower to come on when the oven is turned off
just in case the convection fan compartment
should overheat.