Lincoln 1652 User Manual

SERVICE MANUAL

(DOMESTIC & INTERNATIONAL)

IMPINGER CONVEYOR OVENS

LOW PROFILE - 1600 SERIES

Lincoln Foodservice Products, Inc.

1111 North Hadley Road

P.O. Box 1229

Fort Wayne, Indiana 46801-1229

Phone: [phone] • Fax: [phone]

Technical Service Hot Line

[phone]

www.lincolnfp.com

1600SvcMan REV: 12/13/05

TABLE OF CONTENTS

TABLE OF CONTENTS..............................................................................................................................................2

SEQUENCE OF OPERATIONS 1600 / 1601 / 1652..................................................................................................3

SEQUENCE OF OPERATIONS 1622 / 1623.............................................................................................................4

SEQUENCE OF OPERATIONS / 1628 / 1629...........................................................................................................5

SEQUENCE OF OPERATIONS / 1646, 1647, 1650, 1651........................................................................................7

SCHEMATIC / 1600, 1601, 1652 ...............................................................................................................................9

SCHEMATIC / 1622, 1623........................................................................................................................................10

SCHEMATIC / 1628, 1629........................................................................................................................................11

SCHEMATIC / 1646, 1647, 1650, 1651 ...................................................................................................................12

TROUBLESHOOTING GAS OVENS ......................................................................................................................13

TROUBLESHOOTING / 1622, 1623, 1628, 1629 ...................................................................................................20

TROUBLESHOOTING / 1646, 1647, 1650, 1651 ....................................................................................................26

REMOVAL, INSTALLATION & ADJUSTMENTS .....................................................................................................32

PARTS / GENERAL - 1600 SERIES ........................................................................................................................48

BLOW UP / GENERAL – 1600 SERIES...................................................................................................................49

PARTS / CONTROL BOX, RIGHT- 1600 - 1601 - 1652 ..........................................................................................50

BLOW UP / CONTROL BOX RIGHT – 1600, 1601, 1652 .......................................................................................51

PARTS / CONTROL BOX, LEFT - 1600 - 1601 - 1652 ............................................................................................52

BLOW UP / CONTROL BOX LEFT – 1600, 1601, 1652 ..........................................................................................53

PARTS / CONTROL BOX, RIGHT –1622,1623,1628,1629 .....................................................................................54

BLOW UP / CONTROL BOX RIGHT – 1622,1623,1628,1629 ................................................................................55

PARTS / CONTROL BOX, LEFT 1622,1623,1628,1629 .........................................................................................56

BLOW UP / CONTROL BOX LEFT – 1622, 1623, 1628, 1629................................................................................57

PARTS / CONTROL BOX RIGHT – 1646, 1647, 1650, 1651 ..................................................................................58

BLOW UP / CONTROL BOX RIGHT – 1646,1647,1650,1651 ................................................................................59

PARTS / CONTROL BOX LEFT – 1646, 1647, 1650, 1651 ....................................................................................60

BLOW UP / CONTROL BOX LEFT – 1646,1647,1650,1651...................................................................................61

PARTS / BACK - 1600 SERIES ...............................................................................................................................62

BLOW UP / BACK – 1600 SERIES ..........................................................................................................................63

PARTS / CONVEYOR - 1600 SERIES.....................................................................................................................64

BLOW UP / CONVEYOR – 1600 SERIES ...............................................................................................................65

Low Profile -–1600 Series Service Manual – Dom & Int’l2

SEQUENCE OF OPERATIONS 1600 / 1601 / 1652

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

POWER SUPPLY 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.

CONTROL BOX
AUTO COOL DOWN

MAIN FAN CIRCUIT 120 VAC is permanently supplied to the normally open contacts of the Oven Power

BURNER CIRCUIT Closing the Oven Power Relay energizes the coil of the Burner Relay. The (2)

TEMPERATURE
CONTROL

CONVEYOR DRIVE Closing the Power Switch supplies 120 VAC, through the contact of the Oven Power

TIME/TEMP DISPLAY

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).

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.

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.

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,

NOTE

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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.

OR:
The temperature portion of the display uses a "J" type thermocouple to measure oven
temperature. The thermocouple generates D.C. millivolts proportional to oven
temperature. This millivolt reading is then converted by the display into a temperature
reading.

The oven utilizes (2) Temperature Display systems, one each for the left and right
sides of the cooking chamber.

SEQUENCE OF OPERATIONS 1622 / 1623

MODEL 1622 / 120/208 VAC./.3 PHASE 60 HZMODEL

1623 / 120/240 VAC / 3 PHASE. / 60 H

POWER SUPPLY Electrical power to be supplied to the oven by a five conductor service.

Voltage from the black conductor to the white conductor is 120 VAC.

Black conductor is Hot.
Red conductor is Hot.
Orange conductor is Hot.
White conductor is Dedicated Neutral.

Green conductor is Ground.
CONTROL BOX
AUTO COOL DOWN

MAIN FAN CIRCUIT Electrical power is permanently supplied through (6)- 50 A. fuses to the normally

When the temperature in either one of the Control Boxes reach 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).

open contacts of the mercury contactors. Power is also supplied, through a 10A fuse,
to the Oven Power Switch , through a 3A fuse to a normally open contact of the
Oven Fan Relay, term. # 1 of the 20 minute Time Delay Module and the (2)
normally open Cooling Fan Thermostats. Power is also supplied to a normally open
contact of the the Oven Power Relay. Closing the normally open Oven 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 coil of the oven fan relay, these
normally open contacts now close, supplying 120 VAC to the (2) Main Fans and
to the (2) Control Box Cooling Fans.

HEAT CIRCUIT Closing the Oven Power Relay, supplies 120 VAC, through a 3 A fuse, to the (2)

heat systems.
NOTE: This oven utilizes (2) complete Heat/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 normally closed High Limit
Thermostat (manually re-settable which opens at 660° F, 350°C) through the
normally open Cooling Fan Sail Switch to the Electronic Temperature Control and
the Heat Indicator Light.
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.
TEMPERATURE
CONTROL

CONVEYOR DRIVE Closing the Oven Power Switch supplies 120 VAC, through the contact of the Oven

When the Cooling Fan Sail Switch closes, 120 VAC is supplied to the Temperature

Control. The Temperature Control Potentiometer (2.5K ohm) is adjusted to desired

temperature. The Thermocouple will provide varying millivolts to the Temperature

Controller. TheTemperature Controller supplies 120 VAC to the contactor coil at

intermittent intervals, (closing the Contactor and supplying 208 or 240 VAC to the

Heating Elements) to maintain desired temperature.

Power Relay, to the normally open Conveyor Switch. Closing the Conveyor Switch

supplies 120 VAC, through a 3 Amp Fuse, to the primary of the Conveyor Control

Transformer. The secondary of this Transformer supplies 10 VAC and 29 VAC to the

Low Profile -–1600 Series Service Manual – Dom & Int’l4

TIME/TEMP DISPLAY

Line voltage is permanently supplied through (6) 50 A. fuses, to the normally open mercury

to a normally open contact of the Oven Fan Relay, through a 3A fuse to the primary of the control

(The transformer steps the voltage down to 120 VAC for the control circuit). 120 VAC is permanently

supplied to a normally open contact of the Oven Fan Relay, the (2) normally open cooling fan

terminal #1 of the 20 minute Time Delay Module and to the normally open Power Switch. Closing the

NOTE: The Conveyor Control uses a Sensor and Magnet, mounted on the Conveyor Motor,

Conveyor Control. The Conveyor Control supplies voltage pulses to the Conveyor

Motor. The ConveyorControl Potentiometer varies the frequency of these pulses.

The motor speed will increase or decrease, as the frequency of the pulses increase

or decrease respectively.

Closing the Oven Power Switch supplies 120 VAC, through the contact of the Oven

Power Relay, to the primary of the (2) Time/TempTransformers. 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.

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.

OR:

The temperature portion of the display uses a "J" type thermocouple to measure

oven temperature. The thermocouple generates D.C. millivolts proportional to oven

temperature. This millivolt reading is then converted by the display into a

temperature reading. The oven utilizes (2) Temperature Display systems, one each

for the left and right sides of the cooking chamber.

SEQUENCE OF OPERATIONS / 1628 / 1629

POWER SUPPLY

CONTROL BOX
AUTO COOL DOWN

MAIN FAN CIRCUIT

MODEL 1628 / 380/220 VAC / 3 PHASE / 50 HZ

MODEL 1629 / 415/240 VAC / 3 PHASE / 50 HZ
Electrical power to be supplied to the oven by a five conductor service.
Brown conductor is hot.
Black conductor is hot.
Black conductor is hot.
Blue conductor is neutral.
Green/yellow 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).

contactors, through a 10A fuse,

circuit step down transformer.

thermostats, a normally open contact of the Oven Power Relay,

Power Switch supplies
120 VAC to the Oven Power Relay, its contacts now close, enabling the 20 minute
Time Delay Module. The 20 -minute Time Delay Module supplies 120 VAC to the
Oven Fan Relay, its contacts now close. supplying line voltage to the (2) Main Fan
Motors and 120 VAC to the (2) cooling fans. 120 VAC is also supplied to the (2)
Time/Temp Transformers, the (2) electronic temperature controls and to the normally

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open Conveyor Switch.

Closing the Oven Power Relay supplies 120 VAC, through a 3A fuse, to the (2) Heat/Temperature

NOTE: This oven utilizes (2) complete Heat/Temperature Control systems. The sequence of

120 VAC is supplied through a normally open Air Pressure Switch, (closed by air pressure from the

closed Hi-limit Thermostat, (manually re-settable opens at 350°C (662°F)) through the Cooling Fan

HEAT CIRCUIT

Control systems

operations is the same for both systems,

Main Fan),through the normally

Sail Switch to the Electronic
Temperature Control Board.
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

TEMPERATURE
CONTROL

When the Sail Switch closes, power is applied to the Electronic Temperature Control.
The 2.5 K Ohm Temperature Pot. is
adjusted to the desired temperature. The Thermocouple will provide varying millivolts
to the Temperature Controller. The Temperature Controller supplies 120 VAC to the
contactor coil at intermittent intervals (closing the contactor and supplying 220 or 240
VAC to
the heating elements) to maintain desired temperature

CONVEYOR DRIVE Closing the Oven Power Switch supplies 120 VAC, through the contact of the Oven

Power Relay, to the normally open Conveyor Switch. Closing the Conveyor Switch
supplies 120 VAC, through a 3 Amp Fuse, to the primary of the Conveyor Control
Transformer. The secondary of this Transformer supplies 10 VAC and 29 VAC to the
Conveyor Control. The conveyor control supplies voltage pulses to the Conveyor
Motor. The Conveyor Control Potentiometer varies the frequency of these pulses. The
motor speed will increase or decrease, as the frequency of the pulses increase or
decrease respectively.

TIME/TEMP DISPLAY Closing the Oven Power Switch supplies 120 VAC to the primaries 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. These
pulses are converted by the Time/Temp. Display into a read out of minutes and
seconds.

NOTE: 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.

OR:

The temperature portion of the display uses a "J" type thermocouple to measure oven
temperature. The thermocouple generates D.C. millivolts proportional to oven
temperature. This millivolt reading is then converted by the display into a temperature
reading.

The oven utilizes (2) Temperature Display systems, one each for the left and right
sides of the cooking chamber.

Low Profile -–1600 Series Service Manual – Dom & Int’l6

SEQUENCE OF OPERATIONS / 1646, 1647, 1650, 1651

CONTROL BOX AUTO COOL AUTO

MODEL 1646 / 220-240 VAC / 50 HZ / NATURAL GAS

MODEL 1647 / 220-240 VAC / 50 HZ / L.P. GAS

MODEL 1650 / 220-240 VAC / 50 HZ / TOWN GAS
MODEL 1651 / 220-240 VAC / 50 HZ / TOWN GAS

POWER SUPPLY Electrical power to be supplied to the oven by a three conductor service.

Brown conductor is hot.
Blue 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

COOL DOWN

MAIN FAN CIRCUIT Line voltage is permanently supplied to a normally open contact of the oven power

BURNER CIRCUIT NOTE: This oven utilizes (2) complete Burner/Temp. Control Systems. The sequence

TEMPERATURE
CONTROL

CONVEYOR DRIVE Closing the Oven Power Switch supplies 120 VAC, through the contact of the Oven

TIME/TEMP DISPLAY Closing the Oven Power Switch supplies 120 VAC, through the contact of the Oven

NOTE:

thermostats will interrupt power to the Cooling Fans when the temperature falls to
100°F ± 3°F (37°C ± 1.7°C).

switch, through a 10A fuse to the normally open oven fan relay, and through a 3A
fuse to the primary of the control circuit step down transformer (The transformer steps
the voltage down to 120 VAC for the control circuit). 120 VAC is permanently supplied
to the (2) normally open cooling fan thermostats, a normally open contact of the cool
down relay, terminal #1 of the 20 -minute time delay module and to the normally open
oven power switch. Closing the oven power switch supplies 120 VAC to the cool­down relay, its contacts now close, supplying 120 VAC to the (2) cooling fans. and
enabling the 20 minute time delay module. The 20-minute time delay module supplies
120 VAC to the oven fan relay, its contact now closes supplying line voltage to the (2)
main fan motors. 120 VAC is also supplied to the (2) time/temp transformers, the
conveyor switch and the (2) electronic temperature controls.

of operations is the same for each system. Closing the normally open oven power
switch supplies line voltage through a 3A fuse, through the sail switch, through the
gas pressure switch, through the Main Fan Air Pressure Switch, through the Hi-limit
Thermostat, to the Ignition Control. The combustion motor is energized. The normally
open combustion air switch closes upon sensing air pressure. After a pre-purge
period of between 30 and 60 seconds, the Ignition Transformer and the Main Gas
Valve are energized. Ignition should now occur.
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.
Closing the Oven Power Switch supplies 120 VAC (through the Step Down
Transformer) to the Temperature Control Board. The 2.5k ohm Temperature Pot is
adjusted to desired temperature. The Thermocouple will provide varying millivolts to
the Temperature Controller. The Temperature Controller supplies 120 VAC to the
Solenoid Valve at intermittent intervals to maintain desired temperature.

Power Relay, to the normally open Conveyor Switch. Closing the Conveyor Switch
supplies 120 VAC, through a 3 Amp Fuse, to the primary of the Conveyor Control
Transformer. The secondary of this Transformer supplies 10 VAC and 29 VAC to the
Conveyor Control. The conveyor control supplies voltage pulses to the Conveyor
Motor. The Conveyor Control Potentiometer varies the frequency of these pulses. The
motor speed will increase or decrease, as the frequency of the pulses increase or
decrease respectively.

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. These pulses are 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

Low Profile -–1600 Series Service Manual – Dom & Int’l 7

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.

OR:

The temperature portion of the display uses a "J" type thermocouple to measure oven
temperature. The thermocouple generates D.C. millivolts proportional to oven
temperature. This millivolt reading is then converted by the display into a temperature
reading.

The oven utilizes (2) Temperature Display systems, one each for the left and right
sides of the cooking chamber.

Low Profile -–1600 Series Service Manual – Dom & Int’l8

SCHEMATIC / 1600, 1601, 1652

Low Profile -–1600 Series Service Manual – Dom & Int’l 9

SCHEMATIC / 1622, 1623

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SCHEMATIC / 1628, 1629

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SCHEMATIC / 1646, 1647, 1650, 1651

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TROUBLESHOOTING GAS OVENS

MODEL 1600, 1601, 1652

1600-000-DB, 1601-000-DB

NOTE: When checking components on left side of unit, be sure to check wire harness across back of
oven for proper connections in power connector, (marked P. C. on Schematic Diagram, inside control
box cover).

SYMPTOM POSSIBLE CAUSE EVALUATION

Oven fan(s) will not run

No main fan cool down

Main fan runs after20
minute cool down

No control box cooling

Incoming Power Supply Check breakers/Reset if required/ Call Power

Company if needed.
Power Switch Check continuity between switch terminals.
Oven Power Relay Check for 120 VAC to the relay coil. If voltage is not

present, trace wiring back to the fan switch. If voltage

is present, check to insure contacts are closing.

Check for 120 VAC supplied t terminal #2 of the relay.
20 Minute Time Delay Check for 120 VAC at terminal #1 to neutral on the 20

minute timer. If no voltage is present, trace wiring

back to the power supply. If voltage is present at

terminal #1, check for 120 VAC at terminal #2 to

neutral. If no voltage is present, and the oven power

relay is closed, replace the 20 minute timer.
Oven Fan Relay Check for 120 VAC to coil of the oven fan relay. If no

voltage is present, trace wiring back to terminal #2 of

the 20minute timer. Check for 120 VAC at terminals

#2 and #6 of the relay, if no voltage is present, trace

wiring back to the power supply. If voltage is present

at the relay coil, check to insure the contacts are

closing.
Fuse, Fan, 10A Check, replace if necessary.
Fuseholder Check, replace if necessary
Capacitor(s) Check for opens, shorts, or grounds.
Motor(s)

20 Minute Time Delay Check for 120 VAC at terminal #2 to neutral while

Oven Fan Relay Check if relay is operating and that the contacts

Oven Power Relay Contacts should open when main fan switch is turned

20 Minute Time Delay 120 VAC at terminal #2 should discontinue

Oven Fan Relay Check to insure that the contacts are opening after the

Power Switch
Oven Power Relay
20 Minute Time Delay
Oven Fan Relay
Fuse, Cooling Fans (3A) Check, replace if necessary.
Fuseholder Check, replace if necessary
Cooling Fan(s) 120 VAC should now be at these motors. If voltage is

Check for opens, shorts, or grounds. WITH POWER OFF:

turn the fan blade(s) to check for locked rotor.

oven is "on". Turn off the main fan switch, 120 VAC

should continue to be present for 20 minutes. If

voltage is not present for approx. 20 minutes, replace

the timer.

remain closed during the 20 minute cool down.

off.

approximately 20 minutes after main fan is switched

off. If the oven power relay contacts are open, and the

voltage continues at terminal #2 of the 20 minute

timer, for more than 20 mins., replace the timer.

coil is de-energized.

(SEE MAIN FAN WILL NOT RUN)

present, check motor(s) for shorts, opens, or grounds

WITH POWER OFF: check for locked rotor.

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No automatic control

Centrifugal Switch of Main Fan Motor

Check for 120 VAC supply to the burner blower motor, if 120 VAC is

box cooling

Incoming Power Supply Check circuit breakers, reset if required. Call the

Power Company if needed.
Cooling Fan Thermostat(s) Check the cooling fan thermostat. (Thermostat closes

at 120°F and opens at 100°F.) With the cooling fan

thermostat pre-heated, check for continuity. If switch

is open, replace.
Fuse, Cooling Fans (3A)
Fuseholder
Cooling Fan(s)

Check, replace if necessary.

Check, replace if necessary.

120 VAC should now be at these motors. If voltage is

present, check motor(s) for shorts, opens, or grounds.

WITH POWER OFF: check for locked rotor .

Cooling fans continue
to run after 20 minute
cool down

Cooling Fan Thermostat(s) Thermostat is normally open and may have closed if

control box temperature is 120°F or above.
Oven Fan Relay Check to insure contacts are opening after the 20

minute cool down.

Oven will not heat

Gas Supply Check for adequate gas supply and closed manual

gas shut-off.
Main Fan(s) If not operating, refer to "Oven fan will not run." Page

13 “
Burner relay 120 VAC should be present at the coil of burner relay.

If voltage is not present, trace wiring back to the oven

power relay and back to power supply if needed. If

voltage is present, check to insure the relay contacts

are closing. Replace as necessary

.

NOTE: These ovens utilize 2 complete Burner/Temperature control systems. Each system will
follow the same Troubleshooting Sequence.

Check for 120 VAC supplied to the centrifugal switch, if

voltage is not present, trace the wiring back to the

burner relay. Check for 120 VAC out of the centrifugal

switch. If voltage is supplied to the centrifugal switch,

and motor is running, but there is no voltage out of the

centrifugal switch, replace the fan motor.

(NOTE: see Schematic Diagram for proper wire

numbers on motors)
Fuse, Burner 10A Check, replace if necessary.
Fuseholder Check, replace if necessary.
Burner Blower Motor

present and motor does not run, replace the motor.

WITH POWER OFF: turn blower wheel to check for

locked rotor.
Centrifugal Switch of Burner
Blower Motor

Check for 120 VAC supply to the centrifugal switch of

burner blower motor (see Schematic for proper wire

numbers). If no voltage is present, trace wiring back to

the fuseholder. If voltage is present, check for 120 VAC

at the output of the centrifugal switch. If there is no

output, and the burner blower motor is running, replace

the burner blower motor.

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Control Box Cooling Fan Check to insure the control box cooling fan is operating

properly. If the cooling fan is not operating, refer to "No

control box cooling" Page 14”.
Cooling Fan Sail Switch (NOTE: the cooling fan sail switch is located in front of

the cooling fan and is activated by the air flow from the

cooling fan.) Check for 120 VAC supply to the sail

switch (see Schematic for proper wire numbers).

Visually check to see the sail switch is closing as

cooling fan is running, if the sail switch is not closing,

check for obstructions or damage to the sail switch. If

the sail switch is closing, check for 120 VAC out of the

sail switch. If there is no voltage, and the sail switch is

closed, replace the sail switch.
Burner Transformer Check for 120 VAC to primary of the 24 VAC burner

transformer. If voltage is not present, trace wiring back

to the sail switch. If voltage is present, check for 24

VAC at the secondary, if no secondary voltage is

present, replace the transformer.
Ignition Control Check for 24 VAC supply to the ignition control at

terminals marked 24V and 24Vgnd. If voltage is not

present, trace wiring back to the 24 VAC transformer.

Check for 120 VAC supply to the ignition control at

terminals L1 and L2. If no voltage is present, trace

wiring back to terminal #11 on the temperature control.

If the above checks are okay, proceed. The ignition

control should switch 120 VAC to the hot surface

igniter, across the (2) terminals marked HSI. If no

voltage is present, replace ignition control.
Hot Surface Igniter(located
inside Burner Assy.)

Ignition Control After 45 seconds of hot surface igniter pre-heat, the

Gas Control Valves Check for 24 VAC supplied to the gas control valves. If

If 120 VAC is present at HSI terminals, visually check

to see that the hot surface igniter is heating (igniter

may be viewed through port glass in end of burner

tube). The igniter should glow bright red. Check all

connections to be sure they are tight. If the igniter does

not heat, replace.

ignition control will switch 24 VAC to the gas control

valves. Check for 24 VAC output from the ignition

control, and across terminals marked "valve" and

"valve gnd". If no voltage is present, replace the ignition

control. NOTE: the ignition control contains a safety

lock-out circuit. If a flame is not detected within 6

seconds after the gas control valve is energized, the

ignition control will lock-out. To reset, turn the burner

switch "off", wait 45 seconds and switch the burner

system "on" to retry ignition

voltage is present, the valves should open. Check for

gas pressure at the pressure tap, located in the gas

piping just prior to the burner. If there is no gas

pressure, and the voltage is supplied to valves, check

piping for obstructions. If there are no obstructions,

replace gas control valves. NOTE: the red burner

indicator light is wired in parallel with the gas control

valves. When 24 VAC is supplied to the gas control

valves the red burner indicator light is also energized.

Low Profile -–1600 Series Service Manual – Dom & Int’l 15

Flame will not stay lit

Low flame is on, but
no main flame.

Hot Surface Igniter The ignition control will keep the gas control valves

energized for 6 seconds. At the end of 6 seconds, the

hot surface igniter must sense a flame, or, the ignition

control will go into lock- out. (The ignition control

requires a minimum of 0.8 microamps D.C.) To check

the flame sensing operation, connect a digital

multimeter (capable of measuring D.C. micro-amps)

between the "ground" terminal on ignition control and

the ground lead.

NOTE: This is a current measurement and the meter

must be connected in series. If these readings are not

achieved, check bypass orifice for obstructions, if

bypass orifice is clear, replace the hot surface igniter.

NOTE: The D.C. micro amp test must be conducted

with the oven in low flame (bypass) operation. Turn the

temperature control to its lowest setting
Power Supply If there is sufficient micro-amp current, but the flame

will not stay lit, check for proper polarity of the 120 VAC

power supply
Ignition Control If there is sufficient micro-amp current, and the 120

VAC polarity is correct, but the flame will not stay lit,

replace the ignition control.

NOTE: Check for proper ground connection of the

ignition control.

NOTE: Flame should be
present at this time

Thermocouple Probe WITH POWER ON AND THERMOCOUPLE LEADS

Temperature Control
Potentiometer

Check for 120 VAC supply at terminal #11 to neutral on

the temperature control. If no voltage is present, trace

the wiring back to 10 A fuse. Turn the temperature

adjustment knob to its maximum temperature position

and check for 120 VAC at the load terminal (#9) and

neutral. If 120 VAC is present and unit is not heating,

refer to "Temperature Regulation Valve" for next check.

If 120 VAC is not present, proceed.

ATTACHED TO THE TEMPERATURE CONTROL

BOARD: measure the D. C. millivolt output of these

leads. Refer to the thermocouple chart page 43 for

proper readings. If these readings are not achieved,

replace the thermocouple.

WITH POWER OFF: remove the potentiometer leads

from the temperature control board and measure ohms

from black to white leads. The reading should be from

0 to 2.5k ohms ± 10% as the dial of the potentiometer

is turned throughout its full rotation. From black to red

leads, the reading should be 2.5k ohms ± 10%

(constant) throughout the full rotation of the dial. If

these readings are not achieved, replace the

potentiometer. If the thermocouple probe and the

control potentiometer check good, then the problem is

usually with the temperature control board.

Temperature Regulation
Valve

If 120 VAC is present on the temperature control board

at load terminal (#9) to neutral, check for voltage at the

temperature regulation valve. If voltage is present,

listen for the valve to open and close. Also check for

opens or shorts inthe coil. Replace as necessary.

Low Profile -–1600 Series Service Manual – Dom & Int’l16

Intermittent Heating Thermal/Overload The main fan motors, burner blower motors, and

cooling fan motors are equipped with internal thermal

protection and will cease to operate if overheating

occurs. As the motors overheat and then cool, this will

cause the units to cycle on and off intermittently.

Improper ventilation or preventive maintenance may

cause this. Also, most of the problems listed under

"Oven will not heat" on Page 14 can cause intermittent

failure.

NOTE: The 1600-000-DB series ovens utilize 2 complete conveyor drive systems.

Conveyor will not run

Conveyor Switch Check for 120 VAC to conveyor switch. If no voltage

is present, trace wiring back to the oven fan switch.

WITH POWER OFF: Check continuity between

switch terminals.

Conveyor Fuse (3A) Check, replace if necessary.
Fuseholder Check, replace if necessary.
Conveyor Control
(Stepper) Transformer

Speed Adjustment
Potentiometer

Conveyor Motor
(Stepper) Control

Conveyor Drive(Stepper)
Motor

Check for 120 VAC supply to primary of transformer,

if voltage is not present, trace wiring back to the

fuseholder. If voltage is present check for output

voltage from the transformer secondary

NOTE: this control transformer outputs (2) secondary

voltages

Red Leads 29 VAC

Brown Leads 10 VAC

If BOTH secondary voltages are not present, replace

the transformer.

This is a 0 to 50k ohm, 10 turn Brown Leads 10 VAC

potentiometer.

WITH POWER OFF: remove the 3 pin potentiometer

cable plug from the motor control board. With a

digital multimeter, check the ohm reading across the

red lead to the black lead, this reading should be 50k

ohms ± 5% as the potentiometer is rotated through

its 10 turn rotation. Place the meter leads on the red

lead and white lead. Rotating the potentiometer

slowly, from low to high, the meter should show an

even transition from 0 to 50k ohms ± 5% through the

10 turn rotation of the potentiometer. There should

be no dead or open spots through the 10 turns of the

potentiometer. Check all three leads to ground.

There should be no continuity to ground. If any of the

above checks fail, replace the potentiometer.

NOTE: if the conveyor drive motor becomes jammed

or begins to run at an uncontrolled speed, the

conveyor motor will stop running. To reset, turn off

the conveyor switch, wait 30 seconds, turn the

conveyor switch on. If the motor does not run after

attempting re-set, check for 2 to 29 VAC across the

motor terminals 1 to 2 and 3 to 5 on the conveyor

motor control. If voltage is not present at both sets of

terminals, replace control.

Check the drive sprocket on motor output shaft to

insure that it is tight. Check motor windings;

measurements should be approximately 2 ohms.

Terminal 1-5, 2-6, 3-7, 4-8.

WITH POWER OFF: Turn the motor shaft to check

for jammed gear box. If motor shaft will not turn,

replace conveyor drive (stepper) motor.

Low Profile -–1600 Series Service Manual – Dom & Int’l 17

Time/Temp. Display
inoperative
NOTE: these units utilize
(2) complete temperature
display systems containing
like components.

Temp. display out or
erratic

Temp. display
inaccurate, erratic,
or inoperative

12 VAC Power
Supply(Transformer)

Time/Temp. Display If proper voltage is present at terminals 1, 2, and 3

NOTE: Time/Temp
displays uses two types
of temperature sensor,
Thermistor Probe2 yellow
wires, Thermo- couple
Probe 1 red wire and 1
white wire
Thermistor Probe Disconnect the yellow tipped thermistor leads from

Thermocouple Probe Measure D.C. millivolts at terminals 9 and 10 on the

Power Supply If a strange or unusual behavior is experienced, such

Time/Temp. Display Perform the power supply check, the thermistor

Measure the transformer primary for a nominal 120

VAC input, if voltage is not present, trace wiring back

to the power supply. Measure the secondary output,

which will normally be 12-15 VAC. Voltage across

terminals 1 and 3 on the time/temp. display should

read 12-15 VAC. Terminals 1-2 and 2-3 should be

1/2 the voltage reading 1 to 3. If the above secondary

readings are not achieved, replace transformer.

on time/temp. display, but the display is not lighted,

recheck all connections for tightness. If time/temp.

display is still not operating, replace the time/temp.

display

Connect the thermocouple of a pyrometer to the

thermocouple on the temperature control board. (Be

sure to maintain proper polarity of thermocouple

leads- see Adjustment Section for proper

procedure .) The pyrometer will now indicate oven

temperature

the time/temp. terminals 9 and 10. Measure the

resistance of the thermistor probe. See chart on page

43 for proper resistance readings. Inspect the

thermistor bulb for its proper location in its spring

holder. Check for short in leads where they enter the

sensor bulb. Also check each thermistor lead for

short to ground.

time/temp display. See thermocouple chart on page

43 for proper readings. Replace thermocouple if

proper readings are not achieved. If readings are

correct on the thermocouple, replace time/temp

display.

as a rolling of numbers, or lock-up at a given number,

first check for a display circuit lock-up. A voltage

spike or surge in the incoming power lines may

cause this. To eliminate this condition, remove power

from the time/temp. display by shutting off the main

fan switch for 15 seconds. This should eliminate the

problem. If this does not solve the problem, it may be

coming in through the Commercial power lines.

Suggest that customer contact their power company

for evaluation.

probe check, and then perform the time/temp.

simulator test. Refer to page 36 & 37 for instructions.

Remember, when using the time/temp. simulator,

remove all leads from the back of the time/temp.

display except the 3 power leads. After completion of

the test, and if re-installing time/temp. display back in

the oven, the dip switches must be reset for oven

operation, and the time/temp. display must be

recalibrated. If readings are not achieved, replace

display.

Low Profile -–1600 Series Service Manual – Dom & Int’l18

Time Display inaccurate,
erratic, or inoperative

Perform all checks as in the above evaluation. If the

time check is okay, refer to the next section.

Conveyor Drive
(Stepper) Motor

Magnet Check to insure that the magnet (cemented to shaft

Hall Effect Sensor Check for any physical damage to Hall Effect sensor

Conveyor Drive
(Stepper) Control

Check to see if the conveyor drive (stepper) motor is

running. If motor is not running, refer to "Conveyor

will not run" on Page 23.

of conveyor drive [stepper] motor) has not been

damaged, or come loose from motor shaft. Replace

as needed.

(mounted on conveyor drive [stepper] motor). Check

all wiring and connections for damage.

Check all connections for tightness or proper location

and check all wiring for visible damage. Replace as

needed. If there is still no time display, wire in

(temporarily) a new conveyor drive control. If there is

still no time display, reconnect original conveyor drive

control. Replace Hall Effect Sensor.

Low Profile -–1600 Series Service Manual – Dom & Int’l 19

TROUBLESHOOTING / 1622, 1623, 1628, 1629

ELECTRIC OVENS

NOTE: When checking components on left side of unit, be sure to check wire harness across back of
oven for proper connections in power connectors, (marked P.C. on Schematic Diagram, located inside
motor cover).

SYMPTOM POSSIBLE CAUSE EVALUATION

Oven fan(s) will not
run

Main fan runs after20
minute cool down

Incoming Power Supply Check breakers/Reset if required/ Call Power

Company if needed.
Fuse, Main Fan 10A Check, replace if necessary.

Fuseholder Check, replace if necessary.
Fuse, Transformer 3A 1628 Check, replace if necessary
Fuseholder 1629 Check, replace if necessary
Transformer Power Only 120 VAC +_10% should be present at secondary of

transformer. If proper voltage is not present, check

transformer primary for proper input.
Power Switch Check for 120 VAC to switch Check continuity

between switch terminals.
Oven Power Relay Check for 120 VAC to the relay coil. If voltage is not

present, trace wiring back to the oven power switch.

If voltage is present, check to insure contacts are

closing. Check for 120 VAC supplied to terminal #2

of the relay. If power is not present, trace wiring

back to transformer.
20 Minute Time Delay Check for 120 VAC at terminal #1 to neutral on the

20-minute timer. If no voltage is present, trace wiring

back to the power supply. If voltage is present at

terminal #1, check for 120 VAC at terminal #2 to

neutral. If no voltage is present, and the oven power

relay is closed, replace the 20-minute timer.
Oven Fan Relay Check for 120 VAC to coil of the oven fan relay. If no

voltage is present, trace wiring back to terminal #2

of the 20 minute timer. Check for 120 VAC at

terminal #2 and supply voltage at #6 of the relay, if

no voltage is present, trace wiring back to the power

supply. If voltage is present at the relay coil, check

to insure the contacts are closing.
Capacitor(s) Motor(s) Check for opens, shorts, or grounds.

WITH POWER OFF: turn the fan blade(s) to check

for locked rotor.
20 Minute Time Delay Check for 120 VAC at terminal #2 to neutral while

oven is "on". Turn off the power switch, 120 VAC

should continue to be present for approx.20

minutes. If voltage is not present for approx. 20

minutes, replace the timer.
Oven Fan Relay Check if relay is operating and that the contacts

remain closed during the 20 minute cool down.
Oven Power Relay Contacts should open when power switch is turned

off and coil is de-energized.
20 Minute Time Delay 120 VAC at terminal #2 should discontinue

approximately 20 minutes after main fan is switched

off. If the oven power relay contacts are open, and

the voltage continues at terminal #2 of the 20 minute

timer, replace the timer.
Oven Fan Relay Check to insure that the contacts are opening after

the coil is de-energized.
Fuse, Transformer 3A Check, replace if necessary.

Fuseholder 1628 Check, replace if necessary.

Low Profile -–1600 Series Service Manual – Dom & Int’l20

No control box cooling

No automatic control
box cooling

Cooling fans continue
to run after 20 minute
cool down

Oven will not heat

Transformer, Power 1629
Only

Power Switch
Oven Power Relay
20 Minute Time Delay
Oven Fan Relay
Cooling Fan(s) Check for 120 VAC at the motor(s). If voltage is

Incoming Power Supply Check circuit breakers, reset if required. Call the

Fuse, Transformer 3A Check, replace if necessary.

Fuseholder 1628 Check, replace if necessary

Transformer, Power 1629
Only

Cooling Fan Thermostat(s) Check the cooling fan thermostat(s). (Thermostat

Cooling Fan (s) Check for 120 VAC at the motor. If voltage is

Cooling Fan Thermostat(s) Thermostat is normally open and may have closed if

Oven Fan Relay Check to insure contacts are opening after the 20

Incoming Power Supply Check circuit breakers. Reset if required. Call the

Main Fan(s) If not operating, Refer to "Oven Fan Will Not Run"

Oven Power Relay Check for 120 VAC at terminal #2. If no voltage is

Fuse, Temp. Control (3A) Check, replace if necessary.

Fuseholder Check, replace if necessary.

120 VAC +_ 10% should be present at secondary of

transformer. If proper voltage is not present, check

transformer primary for proper input.

(SEE MAIN FAN WILL NOT RUN)

present, check motor(s) for shorts, opens, or

grounds. If voltage is not present, trace wiring back

to Oven Fan Relay. WITH POWER OFF: check for

locked rotor.

Power Company if needed.

120 VAC +_ 10% should be present at secondary of

transformer. If proper voltage is not present, check

transformer primary for proper input.

closes at 120°F and opens at 100°F) With the

cooling fan thermostat pre-heated, check for

continuity. If switch is open, replace.

present, check motor(s) for shorts, opens, or

grounds.

WITH POWER OFF: check for locked rotor.

control box temperature is 120°F or above.

minute cool down.

Power Company if needed.

Page 13.

present, trace wiring back to power supply. Check to

insure the contacts are closing.

NOTE: These ovens utilize 2 complete heating and temperature control systems. Each system will follow
the same trouble shooting sequence.

Oven Air Pressure Switch
(1628, 1629 only)

Thermostat, High Limit Terminals are normally closed. If open, reset and

Control Box Cooling Fan Check to insure the control box cooling fan is

Low Profile -–1600 Series Service Manual – Dom & Int’l 21

Check for 120 VAC on both sides of switch. If

voltage is present on one side only, check for air

tube blockage. Adjust air switch. If above fails,

replace air pressure switch.

test oven for proper operation. If thermostat will not

hold for maximum oven temperature, and oven is

not exceeding temperature dial setting, check for

proper location of capillary bulb in its spring holder.

If above checks okay, replace Hi-Limit thermostat.

operating properly. If the cooling fan is not

operating, Refer to "No Control

Box Cooling" Page 13.