Sequence Of Operations 1600 / 1601 / 1652 - Lincoln 1600 Service Manual

SEQUENCE OF OPERATIONS 1600 / 1601 / 1652

POWER SUPPLY
CONTROL BOX
AUTO COOL DOWN
MAIN FAN CIRCUIT
BURNER CIRCUIT
TEMPERATURE
CONTROL
CONVEYOR DRIVE
TIME/TEMP DISPLAY
NOTE
Low Profile -–1600 Series Service Manual – Dom & Int'l
MODEL 1600 / 120 VAC / 60 HZ / NATURAL GAS
MODEL 1601 / 120 VAC / 60 HZ /L.P. GAS
MODEL 1652 / 120 VAC / 60 HZ / TOWN GAS
Electrical power to be supplied to the oven by a three conductor cordset. Voltage from
the black conductor to the white conductor is 120 VAC.
White conductor is Neutral.
Green conductor is Ground.
When the temperature in either one of the Control Boxes reaches 120°F ± 3°F (49°C
± 1.7°C), the Cooling Fan Thermostats will switch power to the Cooling Fans. The
thermostats will interrupt power to the Cooling Fans when the temperature falls to
100°F ± 3°F (37°C ± 1.7°C).
120 VAC is permanently supplied to the normally open contacts of the Oven Power
Relay, to terminal #1 of the 20-Minute Time Delay Module, the normally open
contacts of the Fan Relay and to the (2) normally open Cooling Fan Thermostats.
Closing the normally open Power Switch supplies 120 VAC to the coil of the Oven
Power Relay. These normally open contacts now close, enabling the 20-Minute Time
Delay Module. The 20 Minute Time Delay Module supplies 120 VAC to the Oven Fan
Relay, these normally open contacts now close, supplying 120 VAC, through a 10
Amp fuse, to the (2) Main Fan Motors and, through a 3 Amp fuse, to the (2) Control
Box Cooling Fans.
Closing the Oven Power Relay energizes the coil of the Burner Relay. The (2)
normally open contacts now close supplying120 VAC to the (2) burner systems.
NOTE: This oven utilizes (2) complete Burner/Temp. Control Systems. The sequence
of operations is the same for each system.120 VAC is supplied, through the
Centrifugal Switch of the Main Fan Motor (this switch closes when the Main Fan
reaches approximately 1600 R.P.M.) through the 10 Amp Fuse, to the Ignition
Control, the Electronic Temperature Control, and to the Burner Blower Motor. As this
Blower reaches approximately 1600 R.P.M., its internal centrifugal switch will close,
supplying 120 VAC through the cooling fan sail switch to the Burner Transformer.
NOTE: The Cooling Fan Sail Switch is mounted in front of the cooling fan and is
activated by the air flow of the Cooling Fan. The secondary of the Transformer
supplies 24 VAC to the Ignition Control. The Ignition Control operates on both 24 VAC
and 120 VAC. When the control is energized by 24 VAC, 120 VAC is switched to the
Hot Surface Ignitor for 45 seconds for Hot Surface Igniter warm up 24 VAC is now
switched to the Gas Valves which open. Ignitor glows red, and ignition should now
occur. The red Indicator Light is also now energized. If ignition does not occur within 6
seconds, the control will lock out. To retry after lockout, turn off the burner switch, wait
45 seconds, and then turn the switch back on.
When the Centrifugal Switch of the Burner Blower Motor closes, power is applied to
the Temperature Control. The2.5 K ohm Temperature Pot is adjusted to desired
temperature. The thermocouple will provide varying millivolts to theTemperature
Controller. The Temperature Controller supplies 120 VAC to Temperature Regulation
Valve at intermittent intervals to maintain desired temperature.
Closing the Power Switch supplies 120 VAC, through the contact of the Oven Power
Relay, to the primary of the (2) Time/Temp. Transformers. The secondary output of
the Transformers, 12.5 to 15 VAC with a center tap, is supplied to terminals 1, 2, and
3 of the Time/Temp. Display. The Display works on a balanced input, and center tap
voltage to each leg must be 1/2 the total reading.
The speed side of the Time/Temp. Display is supplied, by the Conveyor Control, with
the frequency of the pulses to the Conveyor Motor. This frequency is converted by the
Time/ Temp. Display into a read out of minutes and seconds.
The Conveyor Control uses a sensor and magnet, mounted on the Conveyor Motor,
that senses when the motor is turning. If the motor is not turning, the Time/Temp.
Display will show "--:--" in the window.
The temperature portion of the display uses a Thermistor Probe to sense oven
temperature. The Thermistor outputs a resistance proportional to oven temperature.
This resistance is then converted by the Display into a temperature reading.
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