Vulcan-Hart SG SERIES User manual

SG SERIES GAS CONVECTION
OVENS
MODELS SG4
SG6
STACKED
MODELS
SG44
SG66
- NOTICE -
This Manual is prepared for the use of trained Vulcan Service
Technicians and should not be used by those not properly
qualified.
This manual is not intended to be all encompassing. If you have
not attended a Vulcan Service School for this product, you should
read, in its entirety, the repair procedure you wish to perform to
determine if you have the necessary tools, instruments and skills
required to perform the procedure. Procedures for which you do
not have the necessary tools, instruments and skills should be
performed by a trained Vulcan Service Technician.
The reproduction, transfer, sale or other use of this Manual,
without the express written consent of Vulcan, is prohibited.
This manual has been provided to you by ITW Food Equipment
Group LLC ("ITW FEG") without charge and remains the property
of ITW FEG, and by accepting this manual you agree that you will
return it to ITW FEG promptly upon its request for such return at
any time in the future.
SERVICE MANUAL
A product of Vulcan-Hart 3600 North Point Blvd Baltimore, MD 21222
F45525 (0814)

TABLE OF CONTENTS
GENERAL .................................................................................................. 3
INTRODUCTION ....................................................................................... 3
INSTALLATION ........................................................................................ 3
OPERATION ........................................................................................... 3
CLEANING ............................................................................................. 3
LUBRICATION ......................................................................................... 3
SPECIFICATIONS ...................................................................................... 3
TOOLS ................................................................................................. 3
REMOVAL AND REPLACEMENT OF PARTS ............................................................... 4
COVERS AND PANELS ................................................................................ 4
TOP FRONT COVER ............................................................................... 4
BOTTOM FRONT COVER .......................................................................... 4
CONTROL PANEL ................................................................................. 4
RIGHT SIDE PANEL ................................................................................ 4
CONTROL PANEL COMPONENTS ..................................................................... 5
COMPONENT PANEL COMPONENTS ................................................................. 5
TEMPERATURE PROBE ............................................................................... 6
GAS BURNER ......................................................................................... 6
GAS ORIFICE .......................................................................................... 7
GAS SOLENOID VALVE ................................................................................ 8
IGNITION CONTROL MODULE ......................................................................... 9
SPARK IGNITER AND FLAME SENSE ................................................................ 10
BLOWER AND MOTOR ............................................................................... 10
OVEN DOORS AND BEARINGS (INDEPENDENT DOORS) ............................................ 12
ROLLER LATCH ASSEMBLY (INDEPENDENT DOORS) ............................................... 13
DOOR WINDOW ...................................................................................... 13
DOOR SWITCH ....................................................................................... 14
HIGH LIMIT THERMOSTAT ........................................................................... 14
INTERIOR LIGHTS .................................................................................... 15
COOLING FAN ........................................................................................ 15
SERVICE PRODCEDURES AND ADJUSTMENTS ......................................................... 17
SOLID STATE TEMPERATURE CONTROL CALIBRATION ............................................ 17
SOLID STATE TEMPERATURE CONTROL TEST ..................................................... 18
TEMPERATURE PROBE TEST ....................................................................... 18
GAS VALVE PRESSURE CHECK ..................................................................... 19
VERIFICATION OF SPARK AT IGNITOR .............................................................. 19
DOOR SWITCH ADJUSTMENT ....................................................................... 20
BLOWER ADJUSTMENT .............................................................................. 20
DOOR ADJUSTMENT ................................................................................. 21
DOOR STRIKE ADJUSTMENT (INDEPENDENT DOORS) ............................................. 22
ELECTRICAL OPERATION ................................................................................ 23
COMPONENT FUNCTION ............................................................................ 23
COMPONENT LOCATION ............................................................................. 24
SEQUENCE OF OPERATION ......................................................................... 25
NORMAL CYCLE ................................................................................. 25
COOL DOWN CYCLE (SOLID STATE TEMPERATURE CONTROL) ................................ 27
SCHEMATICS ........................................................................................ 28
WIRING DIAGRAM .................................................................................... 28
TROUBLESHOOTING ..................................................................................... 29
ALL MODELS ......................................................................................... 29
SG SERIES GAS CONVECTION OVENS
© VULCAN 2014
F45525 (0814) Page 2 of 31

GENERAL
INTRODUCTION
Procedures in this manual will apply to all models
unless specified. Pictures and illustrations can be of
any model unless the picture or illustration needs to
be model specific.
MODELS
MODEL
FEATURES OPTIONS
CAVITY
DEPTH
TEMPERTURE
CONTROL DOORS (50/50) COOK TIMER CASTERS BLOWER 208/240/60/1
SG4 26.5" Solid State Independent 1-Hour Dial Optional Optional
SG6 30.5" Solid State Independent 1-Hour Dial Optional Optional
INSTALLATION
Refer to the Installation and Operation Manual for
detailed installation instructions on single or stacked
ovens.
OPERATION
Refer to the Installation and Operation Manual for
specific operating instructions.
CLEANING
Refer to the Installation and Operation Manual for
specific cleaning instructions.
LUBRICATION
• Cavity blower motor has sealed bearings and
requires no additional lubrication.
• Huskey’s TF1000 grease or equivalent high
temperature Teflon grease.
SPECIFICATIONS
Electrical
Voltage - 120/60/1
Amps - 9.0 Amps
Input BTU Rating
Natural Gas - 60,000 BTU input at 3.5 in. W.C.
Propane Gas - 60,000 BTU input at 10.0 in. W.C.
Gas Line Pressures
Natural - Recommend (in. W.C.) 7.0, Min 5.0
Propane - Recommend (in. W.C.) 11.0, Min 11.0
Maximum 14.0 in. W.C. (Nat. or Prop.)
TOOLS
Standard
• Standard set of hand tools.
• VOM with ability to measure micro amp current.
VOM with minimum of NFPA-70E CAT III 600V,
UL/CSA/TUV listed. Sensitivity of at least 20,000
ohms per volt. Meter leads must also be rated at
CAT III 600V.
• Gear Puller to remove blower
Special
• Temperature tester (thermocouple type).
• Manometer
SG SERIES GAS CONVECTION OVENS - GENERAL
Page 3 of 31 F45525 (0814)

REMOVAL AND REPLACEMENT OF PARTS
COVERS AND PANELS
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
SHUT OFF THE GAS BEFORE
SERVICING THE UNIT.
Top Front Cover
1. The top front cover is secured with four (4)
screws, two on each side of cover. Remove these
screws then remove the cover from the oven.
Fig. 1
2. Reverse the procedure to install.
Bottom Front Cover
1. The bottom front cover is secured with four (4)
screws, two on each side of cover. Remove these
screws then remove the cover from the oven.
Fig. 2
2. Reverse the procedure to install.
Control Panel
1. Remove three (3) screws on the right side which
secure the control panel then pull the panel away
from the oven.
Fig. 3
NOTE: If the oven has a mechanical (KX type)
thermostat, it must be removed from the control panel
first, before removing the control panel.
2. Disconnect the temperature probe leads from the
solid state temperature control.
3. Unplug the wire harness connector to the control
panel components.
4. Reverse the procedure to install.
Right Side Panel
1. Remove the screws which secure the right side
of the top front cover, bottom front cover and
control panel.
2. Remove the remaining six screws securing the
right side panel.
Fig. 4
3. Pull the right side panel out at the bottom then
down to remove.
4. Reverse the procedure to install.
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
F45525 (0814) Page 4 of 31

CONTROL PANEL COMPONENTS
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
Removable Components Procedure
1. Remove the CONTROL PANEL.
2. Remove the component being replaced.
3. Reverse the procedure to install the replacement
component, then check oven for proper
operation.
Fig. 5
COMPONENT PANEL
COMPONENTS
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
Removable Components Procedure
1. Remove the as outlined RIGHT SIDE PANEL.
NOTE: If right side panel is not accessible, this
component can be serviced by removing the
CONTROL PANEL.
2. Disconnect the wire leads to the component
being replaced.
3. Remove the component.
4. Reverse the procedure to install the replacement
component and check oven for proper operation.
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
Page 5 of 31 F45525 (0814)

Fig. 6
TEMPERATURE PROBE
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
1. Remove the RIGHT SIDE PANEL.
NOTE: If right side panel is not accessible, this
component can be serviced by removing the
CONTROL PANEL.
2. Disconnect the probe leads from the solid state
temperature control.
3. Remove the racks and right rack support.
4. Remove the probe guard.
Fig. 7
5. Remove probe by pushing it through the oven
wall and into the control panel area.
Fig. 8
NOTE: The hole in the oven cavity wall does not line
up straight with the oven cavity outer shell, therefore
the probe must be removed at an angle.
6. Reverse the procedure to install the replacement
probe.
7. Adjust the temperature control as outlined under
SOLID STATE TEMPERATURE CONTROL
CALIBRATION .
GAS BURNER
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
SHUT OFF THE GAS BEFORE
SERVICING THE UNIT.
1. Remove the BOTTOM FRONT COVER.
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
F45525 (0814) Page 6 of 31

2. Disconnect the ignition cable and the flame
sense lead wire.
Fig. 9
3. Disconnect the ignition cable and the flame
sense lead wire.
Fig. 10
4. Remove the screws securing the burner cover
then lift out.
Fig. 11
5. Grasp the burner and lift out.
Fig. 12
6. Reverse procedure to install the replacement
burner.
NOTE: Ensure that burner positioning bracket (U
shaped end) is inserted into slot at the rear of the
burner chamber.
7. Check for proper operation.
GAS ORIFICE
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
SHUT OFF THE GAS BEFORE
SERVICING THE UNIT.
1. Remove the BOTTOM FRONT COVER.
2. Remove the bolts securing the gas manifold to
the oven and place the manifold to the side.
Fig. 13
3. Remove the gas orifice from the spud on the
manifold and replace with the correct orifice for
the given altitude.
Fig. 14
4. Reverse procedure to install and check for proper
operation.
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
Page 7 of 31 F45525 (0814)

GAS SOLENOID VALVE
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
SHUT OFF THE GAS BEFORE
SERVICING THE UNIT.
All gas joints disturbed during
servicing must be checked for leaks. Check with a
soap and water solution (bubbles). Do not use an open
flame.
1. Remove the Control Panel and the RIGHT SIDE
PANEL.
NOTE: If is right side panel not accessible, this
component can be serviced by removing the
CONTROL PANEL.
2. Disconnect the lead wires.
3. Disconnect the compression fittings to the valve.
Fig. 15
4. Loosen the bolts securing the valve and bracket
assembly then remove the screws securing the
valve to the bracket.
Fig. 16
5. Verify new gas valve is configured for the proper
gas type
Fig. 17
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
F45525 (0814) Page 8 of 31

Fig. 18
A. To change gas type unscrew and reverse
cap to show the proper gas type.
1) Make sure gasket is positioned
between cap and valve
body.
Fig. 19
6. Reverse the procedure to install the replacement
gas valve.
7. Check pressure as outlined under GAS VALVE
PRESSURE CHECK
IGNITION CONTROL MODULE
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
SHUT OFF THE GAS BEFORE
SERVICING THE UNIT.
1. Remove the RIGHT SIDE PANEL.
NOTE: If right side panel is not accessible, this
component can be serviced by removing the
CONTROL PANEL.
2. Loosen the screws securing the mounting
bracket to the component panel and remove the
bracket.
Fig. 20
3. Disconnect the lead wires and igniter cable from
the ignition module board.
Fig. 21
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
Page 9 of 31 F45525 (0814)

4. Remove the ignition module board from the
mounting bracket.
5. Reverse the procedure to install the replacement
ignition module board.
SPARK IGNITER AND FLAME
SENSE
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
SHUT OFF THE GAS BEFORE
SERVICING THE UNIT.
1. Remove the gas burner as outlined under GAS
BURNER.
2. Remove the screws securing the ignitor and
flame sense to burner then remove the
assembly.
Fig. 22
3. Reverse the procedure to install the assembly
and check for proper operation.
NOTE: Check to ensure the spark gap distance is
approximately 1/8". If the gap appears to be excessive
or poor sparking is occurring then adjust.
Fig. 23
BLOWER AND MOTOR
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
SHUT OFF THE GAS BEFORE
SERVICING THE UNIT.
1. Take out the racks and rack supports.
2. Remove screws securing the “snorkel” and
remove the snorkel.
Fig. 24
3. Remove screws securing baffle panel and
remove the panel.
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
F45525 (0814) Page 10 of 31

Fig. 25
4. If replacing:
A. Blower Only - Loosen set screws on blower
hub and using a bearing puller, remove
blower from motor shaft.
1) Reverse procedure to install and adjust
blower position as outlined under
BLOWER ADJUSTMENT.
B. Motor - perform step 4A and continue
procedure.
5. Remove the screws securing the air baffle to the
rear wall at the lower right hand corner.
Fig. 26
6. Remove the nuts that secure the motor mounting
plate to the rear wall.
Fig. 27
7. Place a piece of cardboard on the bottom of the
oven cavity to protect its surface from any
damage during motor assembly removal.
8. Pull the motor assembly into the oven cavity and
place it on the cardboard.
9. Remove the junction box cover from the motor,
disconnect lead wires and remove the conduit.
10. Remove motor mounting bolts and flat washers
then lift the motor from the mounting plate.
11. Position the replacement motor on the motor
mounting plate and install mounting bolts and
washers. Hand tighten mounting bolts only.
12. Reconnect lead wires at the motor, replace
conduit and junction box cover.
NOTE: Check data plate on motor for wiring
schematic. The motor must rotate clockwise when
viewed from the shaft end.
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
Page 11 of 31 F45525 (0814)

Fig. 28
13. Slide blower onto motor shaft until hub is flush
with end of shaft then tighten set screws.
14. Adjust motor position until blower is parallel to
motor mounting plate as outlined under
BLOWER ADJUSTMENT.
15. Position motor mounting plate on the rear wall
and secure with nuts and washers.
16. Replace the baffle panel and “snorkel”.
17. Replace the air baffle on the rear wall at the lower
right hand corner.
18. Remove cardboard from the bottom of the oven
cavity.
19. Install rack guides and racks.
20. Check oven for proper operation.
OVEN DOORS AND BEARINGS
(INDEPENDENT DOORS)
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
1. Remove the TOP FRONT COVER and BOTTOM
FRONT COVER.
2. Remove the door switch lever.
Fig. 29
3. Remove the lower door seal strip to expose the
mounting screws of the door assembly.
4. Remove the two (2) lower sill bolts by the lower
door shaft and the four (4) counter-sunk screws
from the lower sill.
Fig. 30
NOTE: The door assembly is heavy and will drop
down once the last screw is removed. If removing door
assembly with-out assistance, the ignition cable,
flame sense lead and gas manifold should also be
removed to avoid damage to these components.
5. Tilt the top of the door slightly forward and lift the
door up until the bottom of the door shaft clears
the opening in the sill.
6. Lay the door flat to prevent damage.
7. The top and bottom bearings are now accessible
for inspection and/or replacement if needed.
A. If bearings are ok, proceed to step 8.
B. If replacing the top bearing, remove the top
bearing retainer and top bearing.
Fig. 31
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
F45525 (0814) Page 12 of 31

C. If replacing the bottom bearing, remove it
from the door shaft or the lower sill opening.
8. Reverse procedure to install door assembly and
check for proper adjustment as outlined under
DOOR ADJUSTMENT and DOOR SWITCH
ADJUSTMENT.
ROLLER LATCH ASSEMBLY
(INDEPENDENT DOORS)
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
1. Remove the screws that attach roller latch
assembly to door.
Fig. 32
2. Reverse procedure to install.
DOOR WINDOW
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
1. Remove the screws at the top and bottom of
door.
Fig. 33
2. Independent doors:
A. Remove the door handle then remove the
outer door panel.
B. Lift out the inner door panel and window
assembly.
NOTE: Left door only - remove door seal from the
inside edge of the door.
3. Simultaneous doors:
A. If replacing window on the left door, remove
the handle from the front of the door then
remove door seal from the inside edge of the
door.
1) Lift out the inner door panel and
window assembly.
2) If replacing window on the right door,
remove the screws along the inside
edge (if applicable) of the door then
remove the inner door panel and
window assembly.
4. Remove the screws securing the window “tabs”
to the door bracket and lift the window assembly
out from the door frame.
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
Page 13 of 31 F45525 (0814)

Fig. 34
5. Reverse procedure to install the replacement
window.
DOOR SWITCH
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
1. Remove the TOP FRONT COVER.
2. Disconnect the lead wires to the door switch.
3. Remove the switch.
Fig. 35
4. Reverse procedure to install the replacement
switch and check for proper adjustment as
outlined under DOOR SWITCH ADJUSTMENT.
HIGH LIMIT THERMOSTAT
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
1. Take out racks from the oven.
2. Remove the high limit thermostat cover/mounting
plate from inside the oven cavity at the top.
Fig. 36
3. Disconnect lead wires from high limit thermostat
then remove high limit thermostat from cover/
mounting plate.
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
F45525 (0814) Page 14 of 31

Fig. 37
NOTE: Remove the old RTV from the cover and
mating surfaces inside the oven cavity and apply new
RTV before installing.
4. Reverse procedure to install.
INTERIOR LIGHTS
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
Lamp
1. Remove the racks.
2. Unscrew the glass lens for the light being
replaced then unscrew the bulb.
Fig. 38
3. Replace bulb then reverse the procedure to
install.
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
Lamp Assembly
1. Remove the lens and bulb.
2. Remove the springs from the retaining tabs (2
places) on the socket.
Fig. 39
3. Depress the retaining tabs and pull the socket out
from the oven, far enough to disconnect the lead
wires.
4. Remove the socket from the oven.
5. Attach the lead wires to the replacement socket.
6. Insert the socket into the hole in the oven and
push until the socket is held in place by the
retaining tabs.
7. Install the light bulb and lens.
8. Check for proper operation.
COOLING FAN
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
1. Remove the RIGHT SIDE PANEL.
NOTE: If right side panel is not accessible, this
component can be serviced by removing the
CONTROL PANEL.
2. Disconnect the lead wires to the fan motor by
removing wire nuts.
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
Page 15 of 31 F45525 (0814)

3. Remove the screws securing the air deflector to
the fan then loosen the tab screw holding the fan
to the component panel. Rotate the tab so that
the fan will clear and remove the fan.
Fig. 40
4. Reverse the procedure to install the replacement
fan and check for proper operation.
NOTE: The fan must be installed so air is pulled from
the rear of the oven and blown into the control area.
The arrow on the fan body indicates “air flow” direction
and should be pointing toward the controls.
NOTE: Ensure fan is seated “squarely” against the air
tube and the oven bottom.
NOTE: The air deflector should be angled upwards
at approximately 30 degrees to properly direct the air
flow.
SG SERIES GAS CONVECTION OVENS - REMOVAL AND REPLACEMENT OF PARTS
F45525 (0814) Page 16 of 31

SERVICE PRODCEDURES AND ADJUSTMENTS
Certain procedures in this section require electrical test or measurements while
power is applied to the machine. Exercise extreme caution at all times and follow Arc Flash
procedures. If test points are not easily accessible, disconnect power and follow Lockout/Tagout
procedures, attach test equipment and reapply power to test.
SOLID STATE TEMPERATURE
CONTROL CALIBRATION
1. Place a thermocouple in the geometric center of
the oven cavity.
2. Set the ON-OFF-COOL DOWN switch to ON.
3. Set the NORMAL - GENTLE BAKE switch to
NORMAL.
4. Set the temperature control dial to 350°F.
5. Allow the oven temperature to stabilize (normally
3 cycles).
6. Record the temperature at which the Heat lamp
goes OFF and comes ON for at least two
complete heating cycles.
7. Calculate the differential by subtracting the
temperature indicated when the lamp goes out
from the temperature indicated when the lamp
comes on.
Differential = Heat lamp OFF - Heat lamp ON
Example: 360° (lamp off) - 340° (lamp on) =
20°
A. The differential calculated should be less
than 20 °F.
1) If the differential is less than 20 °F, the
temperature control circuit is
functioning properly.
a. Proceed to Step 8.
2) If the differential is more than 20 °F:
a. Check the temperature probe as
outlined under TEMPERATURE
PROBE TEST .
b. If the probe is functioning properly
then temperature control is
malfunctioning.
a) Install a replacement
temperature control and
check calibration.
8. Calculate the average temperature by adding the
temperature indicated when the lamp goes out to
the temperature indicated when the lamp comes
on and dividing this answer by 2.
[Temp. (lamp off) + Temp. (lamp on)] ÷ 2 =
Average Temp. Example: (360° + 340°) ÷ 2 =
350°
A. If the average temperature is less than 10
°F from the dial setting, the thermostat is
properly calibrated.
B. If the average temperature is more than 10
°F from the dial setting, the thermostat
calibration must be adjusted.
1) Loosen the temperature control knob
set screw and remove the knob from
the stem.
2) Access the adjustment potentiometer
located at the 3 o'clock position.
a. Turn clockwise to increase,
counterclockwise to decrease
temperature
b. Repeat the average temperature
calculation in Step 8.
NOTE: Allow the oven to cycle at least two times
between adjustments before performing the
calculation.
a) If the average temperature
still differs more than 10 °F
from the dial setting, adjust
the thermostat calibration
until the average
temperature is within
tolerance.
C. If the above adjustment cannot be obtained,
replace the temperature control and check
calibration.
SG SERIES GAS CONVECTION OVENS - SERVICE PRODCEDURES AND ADJUSTMENTS
Page 17 of 31 F45525 (0814)

SOLID STATE TEMPERATURE
CONTROL TEST
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
1. Remove the RIGHT SIDE PANEL.
NOTE: If right side panel is not accessible, this
component can be serviced by removing the
CONTROL PANEL.
2. Place a thermocouple in the geometric center of
the oven cavity.
NOTE: Oven temperature must be below 450°F.
3. Set the temperature control to the maximum
setting.
4. Check machine data plate for correct voltage to
oven. Refer to diagram below for proper terminal
locations and voltages before checking the
control. Use the correct terminals for the
corresponding voltage.
5. Turn the ON-OFF-COOL DOWN switch to ON.
Fig. 41
6. Check for proper voltage across terminalsT1 &
T2 (120VAC) or terminals T1 & T3 (208-240VAC)
for power to the control.
A. If correct, proceed to step 7.
B. If incorrect, problem is not with the
temperature control. See
TROUBLESHOOTING.
7. Check relay voltages on the board:
A. For 120VAC controls - check across
terminals T4 & T2 for input to the internal
relay and T5 & T2 for output from the internal
relay.
B. For 208-240VAC controls - check across
terminals T4 & T3 for input to the internal
relay and T5 & T3 for output from the internal
relay.
1) If input voltage to the internal relay is
correct, proceed to Step 8. If input
voltage to the internal relay is not
present, problem is not with the
temperature control (See
TROUBLESHOOTING).
2) If output voltage from the internal relay
is correct proceed to Step 8. If output
voltage from the internal relay is not
correct, check temperature probe as
outlined under TEMPERATURE
PROBE TEST
8. Set the temperature control to the minimum
setting.
NOTE: Oven temperature must be above 300°F.
9. Check for zero (0) volts AC across terminals T5
& T2 (120VAC) or T5 & T3 (208-240VAC) for no
output from the internal relay.
TEMPERATURE PROBE TEST
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
NOTE: The temperature probe used in conjunction
with the Solid State Temperature control is an RTD
(resistance temperature detector) of the Thermistor
type. As temperature increases the resistance value
decreases.
1. Remove the RIGHT SIDE PANEL.
NOTE: If right side panel is not accessible, this
component can be serviced by removing the
CONTROL PANEL.
2. Place a shielded thermocouple in the geometric
center of the oven cavity and determine the
temperature in the oven cavity.
3. Remove the probe lead wires from the solid state
temperature control.
4. Test the probe with an ohmmeter.
SG SERIES GAS CONVECTION OVENS - SERVICE PRODCEDURES AND ADJUSTMENTS
F45525 (0814) Page 18 of 31

A. If the measured resistance values are inside
the given tolerance then the probe is
functioning properly.
B. If the measured resistance values are
outside the given tolerance then replace the
probe and retest.
1) Check oven for proper operation.
5. Reverse procedure to install.
TEMP (°F) OHMS* TEMP (°F) OHMS*
77 90,000 360 822
240 4,077 380 656
260 3,016 400 529
280 2,266 425 424
300 1,726 450 334
320 1,332 475 266
340 1,041
(*) Resistance in ohms ± 10%
GAS VALVE PRESSURE CHECK
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
1. Turn gas supply off at manual shutoff valve.
2. Remove the RIGHT SIDE PANEL.
NOTE: If right side panel is not accessible, this
component can be serviced by removing the
CONTROL PANEL.
3. Remove the plug from the manifold pressure
port.
Fig. 42
4. Install hose barb adapter and attach manometer
tube.
5. Turn gas supply to the oven back on.
6. Plug the unit in and turn the power switch ON.
7. Set the temperature control to its highest setting
and allow burner to ignite.
NOTE: The burner must be lit during test.
NOTE: Accurate gas pressure readings can only be
made with the gas on and the burner lit.
GAS TYPE
PRESSURE READINGS (IN W.C.)
MANIFOLD LINE
RECOMMENDED MIN MAX
Natural 5.0 8.0 6.0 14.0
Propane 10.0 11.0 11.0
NOTE: If the incoming line pressure to the valve is
less than the minimum stated, then the manifold
pressure will not be maintained
VERIFICATION OF SPARK AT
IGNITOR
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
SG SERIES GAS CONVECTION OVENS - SERVICE PRODCEDURES AND ADJUSTMENTS
Page 19 of 31 F45525 (0814)

SHUT OFF THE GAS BEFORE
SERVICING THE UNIT.
1. Remove the BOTTOM FRONT COVER.
2. Disconnect the high voltage "ignition cable" from
the spark ignitor.
Fig. 43
DO NOT HOLD THE WIRE WITH
YOUR HANDS FOR THIS TEST. THE MANUAL GAS
VALVE MUST BE CLOSED.
3. Clamp the ignition cable in a manner that will
position the end of the cable 3/16" from the oven
frame (bare metal surface).
NOTE: It is critical that the cable be held 3/16" away
from the surface of the oven frame or sparking may
not occur even though the sparking circuit is
functioning properly.
Fig. 44
4. Plug the oven in and set the temperature control
to the maximum setting.
5. Turn the power switch ON.
6. Sparking should occur after a 4 second delay, for
a duration of 7 seconds then repeat twice after a
15 second purge time. Arching from the ignition
cable to the oven frame should be observed.
DOOR SWITCH ADJUSTMENT
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
1. Remove the Top Front Cover.
2. Door operation:
A. Independent doors - The switch actuator
should be operated by the switch lever when
the right door is between 1" and 1 ½" from
being closed.
B. Simultaneous doors - The switch actuator
should be operated by the switch lever when
the right door is ½" from being closed.
3. If adjustment is necessary, bend the switch
actuator to obtain the proper setting.
Fig. 45
4. Install the top front cover
5. Apply power to the oven and check for proper
operation.
BLOWER ADJUSTMENT
Disconnect the
electrical power to the machine and
follow lockout / tagout procedures.
SHUT OFF THE GAS BEFORE
SERVICING THE UNIT.
1. Remove the blower motor and mounting
assembly by following steps 1 through 8 as
outlined under BLOWER AND MOTOR.
2. Loosen the motor mounting bolts.
SG SERIES GAS CONVECTION OVENS - SERVICE PRODCEDURES AND ADJUSTMENTS
F45525 (0814) Page 20 of 31