Vulcan VC4ED Service Manual
SERVICE MANUAL
VC4E & VC6E
SERIES
FULL SIZE
ELECTRIC CONVECTION
OVENS
MODEL ML
VC4ES 126743
VC4ED 126744
VC4EC 126745
VC6ES 126746
VC4ED SHOWN
VC6ED 126747
VC6EC 126748
- NOTICE -
This Manual is prepared for the use of trained Vulcan Service
Technicians and should not be used by those not properly qualified.
If you have attended a Vulcan Service School for this product, you
may be qualified to perform all the procedures described in this
manual.
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.
Reproduction or other use of this Manual, without the express
written consent of Vulcan, is prohibited.
A product of VULCAN-HART LOUISVILLE, KY 40201-0696
F25105 (Rev. A, October 2007)
FULL SIZE ELECTRIC CONVECTION OVENS
TABLE OF CONTENTS
GENERAL ................................................................................4
Introduction ............................................................................ 4
Installation ............................................................................ 4
Operation ............................................................................. 4
Cleaning .............................................................................. 4
Lubrication ............................................................................ 4
Tools................................................................................. 4
Specifications .......................................................................... 5
REMOVAL AND REPLACEMENT OF PARTS .................................................... 6
Covers and Panels ...................................................................... 6
Control Panel Components ............................................................... 7
Component Panel Components ............................................................ 8
Temperature Probe (Solid State Control) ..................................................... 8
Heating Elements ....................................................................... 9
Blower and Motor ...................................................................... 10
Door Switch .......................................................................... 11
Door Window ......................................................................... 12
Oven Doors and Bearings (Independent Doors) .............................................. 12
Oven Doors (Simultaneous Doors) ......................................................... 13
Roller Latch Assembly .................................................................. 14
Door Catch Roller Assembly (Independent Doors) ............................................ 14
Mechanical (KX) Thermostat ............................................................. 15
High Limit Thermostat .................................................................. 15
Interior Lights ......................................................................... 16
Cooling Fan .......................................................................... 16
SERVICE PROCEDURES AND ADJUSTMENTS ................................................. 17
Solid State Temperature Control Calibration ................................................. 17
Mechanical (KX) Thermostat Calibration .................................................... 18
Solid State Temperature Control Test ...................................................... 19
Temperature Probe Test (Solid State Control) ................................................ 20
Heating Element Test ................................................................... 20
Blower Adjustment ..................................................................... 21
Door Adjustment....................................................................... 22
Door Strike Adjustment (Independent Doors) ................................................. 22
Door Catch Roller Adjustment (Independent Doors) ........................................... 23
Door Switch Adjustment ................................................................. 24
Door Chain Adjustment (Simultaneous Doors) ................................................ 24
Computer Control ...................................................................... 25
Computer Control Temperature Calibration .................................................. 26
F25105 (Rev. A, October 2007) Page 2 of 60
FULL SIZE ELECTRIC CONVECTION OVENS
Computer Control Operational Test ........................................................ 27
ELECTRICAL OPERATION .................................................................. 29
Component Function ................................................................... 29
Component Location ................................................................... 30
Sequence of Operation .................................................................. 34
VC4ES, VC6ES with Mechanical KX Thermostat.......................................... 34
VC4ED, VC6ED with Solid State Temperature Control ..................................... 34
Timer Cycle, Cooking (KX Thermostat or Solid State Control)................................ 34
Cool Down Cycle (KX Thermostat or Solid State Control) ................................... 35
VC4EC, VC6EC (Computer Control) ................................................... 35
Temperature and Time Cycle (Cooking) ............................................. 36
Cook and Hold Cycle ........................................................... 36
Cool Down Cycle .............................................................. 36
Schematics ........................................................................... 37
VC4ES, VC6ES with Mechanical (KX) Controls, 208-240V .................................. 37
VC4ES, VC6ES with Mechanical (KX) Controls, 480V ..................................... 38
VC4ED, VC6ED with Solid State Temperature Control, 208-240V ............................ 39
VC4ED, VC6ED with Solid State Temperature Control, 480V ................................ 40
VC4EC, VC6EC Computer Control, 208-240V (Roast & Hold Standard) ........................ 41
VC4EC, VC6EC Computer Control, 480V (Roast & Hold Standard) ........................... 42
Wiring Diagrams ....................................................................... 44
VC4ES, VC6ES with Mechanical (KX) Control, 208-240V ................................... 44
VC4ES, VC6ES with Mechanical (KX) Control, 480V ...................................... 46
VC4ED, VC6ED with Solid State Temperature Control, 208-240V ............................ 48
VC4ED, VC6ED with Solid State Temperature Control, 480V ................................ 50
VC4EC, VC6EC Computer Control, 208-240V (Roast & Hold Standard) ........................ 52
VC4EC, VC6EC Computer Control, 480V (Roast & Hold Standard) ........................... 54
TROUBLESHOOTING ...................................................................... 56
All Models ............................................................................ 56
Computer Control Models Only ........................................................... 57
© Vulcan 2007
F25105 (Rev. A, October 2007)Page 3 of 60
FULL SIZE ELECTRIC CONVECTION OVEN - GENERAL
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
FEATURES OPTIONS
MODEL
VC4ES
VC4ED
VC4EC
VC6ES
VC6ED
VC6EC
NOTES:
4
4
CAVITY
DEPTH
26.5" Mechanical (KX) Independent
26.5" Solid State Independent
26.5" Computer Independent
30.5" Mechanical (KX) Independent
30.5" Solid State Independent
30.5" Computer Independent
1. Simultaneous doors are optional (with or w/o window).
2. Stainless steel doors w/o window (standard).
3. Stainless steel doors with window (standard)
4. In February 2001, this model was discontinued.
TEMPERATURE
CONTROL
DOORS
(50/50)
1, 2
1-Hour Dial 5-Hour Dial N/A
1, 3
1-Hour Dial 5-Hour Dial N/A
1, 3
24-Hour Digital Built in Built in
1, 2
1-Hour Dial 5-Hour Dial N/A
1, 3
1-Hour Dial 5-Hour Dial N/A
1, 3
24-Hour Digital Built in Built in
COOK
TIMER
COOK
TIMER
COOK &
HOLD
INSTALLATION
Refer to the Instructions Manual for detailed
installation instructions on single or stacked ovens.
OPERATION
Refer to the Instructions Manual for specific
operating instructions.
CLEANING
Refer to the Instructions 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.
TOOLS
Standard
! Standard set of hand tools
! VOM with A.C. current tester (Any quality VOM
with a sensitivity of at least 20,000 ohms per volt
can be used)
! Gear Puller to remove blower
! Temperature tester (thermocouple type)
Special
! Manometer
! Clamp on amp meter
! Spring force gauge, pull type with a minimum 30
pound full scale range (purchase locally)
! RTV sealant, 736 DOW silicone high temp (P/N
542133) or equivalent
F25105 (Rev. A, October 2007) Page 4 of 60
Electrical
FULL SIZE ELECTRIC CONVECTION OVEN - GENERAL
SPECIFICATIONS
AMPERAGE - 3 PHASE/ 60HZ
MODEL
VC4ES
VC4ED
VC4EC
VC6ES
VC6ED
VC6EC
NOTES:
MODEL
TOTAL
POWER
(KW)
PER LINE
1
RECOMMENDED
CIRCUIT
PROTECTION
2
208V 240V 480V 208V 240V 480V
12.5 353315454020
1. Amperage values in the table are nominal. Tolerance
is +5/-10%.
2. Complied in accordance with National Electric Code,
ANSI/NFPA 70, latest edition.
AMPERAGE - 1 PHASE/ 60HZ
TOTAL
POWER
(KW)
PER LINE
1
RECOMMENDED
CIRCUIT
PROTECTION
2
VC4ES
VC4ED
VC4EC
VC6ES
VC6ED
VC6EC
NOTES:
208V 240V 480V 208V 240V 480V
12.5 605226807035
1. Amperage values in the table are nominal. Tolerance
is +5/-10%.
2. Complied in accordance with National Electric Code,
ANSI/NFPA 70, latest edition.
F25105 (Rev. A, October 2007)Page 5 of 60
FULL SIZE ELECTRIC CONVECTION OVEN - REMOVAL AND REPLACEMENT OF PARTS
REMOVAL AND REPLACEMENT OF PARTS
COVERS AND PANELS
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.
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.
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.
3. Unplug the wire harness connector to the
control panel components.
4. Reverse the procedure to install.
Right Side Panel
1. Remove the two screws near front of oven,
which secure the bottom front cover and control
panel.
2. Remove the remaining seven screws securing
the right side panel.
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.
F25105 (Rev. A, October 2007) Page 6 of 60
3. Pull the right side panel out at the bottom then
4. Reverse the procedure to install.
down to remove.
FULL SIZE ELECTRIC CONVECTION OVEN - REMOVAL AND REPLACEMENT OF PARTS
Left Side Panel
1. Remove the screws which secure the left side
of the top front cover, bottom front cover and
control panel.
2. Remove the seven screws securing the left side
panel.
3. Pull the left side panel out at the bottom then
down to remove.
4. Reverse the procedure to install.
CONTROL PANEL
COMPONENTS
Removable Components
1. Remove the control panel as outlined under
COVERS AND PANELS.
2. Remove the component being replaced.
3. Reverse the procedure to install the
replacement component, then check oven for
proper operation.
F25105 (Rev. A, October 2007)Page 7 of 60
FULL SIZE ELECTRIC CONVECTION OVEN - REMOVAL AND REPLACEMENT OF PARTS
COMPONENT PANEL
COMPONENTS
Removable Components
1. Remove the right side panel as outlined under
COVERS AND PANELS.
NOTE: If right side panel is not accessible, this
component can be serviced by removing the control
panel as outlined under COVERS AND PANELS.
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.
TEMPERATURE PROBE
(SOLID STATE CONTROL)
1. Remove the right side panel as outlined under
COVERS AND PANELS.
NOTE: If right side panel is not accessible, this
component can be serviced by removing the control
panel as outlined under COVERS AND PANELS.
2. Disconnect the probe leads from the solid state
temperature control.
3. Remove the racks and right rack support.
4. Remove the probe guard or mounting clips.
F25105 (Rev. A, October 2007) Page 8 of 60
FULL SIZE ELECTRIC CONVECTION OVEN - REMOVAL AND REPLACEMENT OF PARTS
5. Remove probe by pushing it through the oven
wall and into the control panel area.
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.
A. Measure the current draw of the heating
elements as outlined under HEATING
ELEMENT TEST in SERVICE
PROCEDURES AND ADJUSTMENTS.
4. From inside the oven cavity, remove the
perforated panel from the same side of the
element being replaced.
6. Reverse the procedure to install the
replacement probe.
7. Adjust the temperature control as outlined under
SOLID STATE TEMPERATURE CONTROL
CALIBRATION in SERVICE PROCEDURES
AND ADJUSTMENTS.
HEATING ELEMENTS
NOTE: Starting with production in October, 2001, the
top cavity panel will have 3/4" square holes for easier
element removal. Ovens manufactured prior to this
date have 1/2" round holes that sometimes make it
difficult to remove elements thru the cavity. A serial
number cut off will not
procedures for element removal as outlined below.
Front Access
be available. Follow the
A. If removing the right side panel, also
remove the probe guard or mounting clips.
B. Run the probe wire thru the panel opening
before lifting panel out.
5. From the element being replaced, remove the
hold down clamps, the mounting bracket screws
at the top, then remove the element.
1. Remove the oven racks and rack supports.
2. Remove the "top" door seal from the oven.
3. Determine if the heating element to replace is
on the left
element locations from front to back are: Right
side - R1, R2 & R3; Left side - R4, R5 & R6.
or right side in the oven cavity. The
F25105 (Rev. A, October 2007)Page 9 of 60
FULL SIZE ELECTRIC CONVECTION OVEN - REMOVAL AND REPLACEMENT OF PARTS
LEFT SIDE ELEMENTS SHOWN
NOTE: The mounting bracket is sealed with RTV
which may still hold the element after the screws are
removed. Also, in some cases, the ring terminal
connected to the element may interfere with easy
removal. If access to the left side panel and/or the
top panel is available, see ALTERNATE ACCESS.
6. Disconnect the lead wires from the element.
7. Clean RTV residue from the mating surface
inside the oven, apply new high temperature
RTV to the heating element mounting bracket
and reverse procedure to install.
A. Remove the top panel and pull back the
insulation to expose the element terminals.
B. Remove the lead wires from the element
being replaced.
4. From the same element, remove the two
clamps holding the element vertical, the screw's
securing mounting bracket at the top, and then
remove the element.
NOTE: The mounting bracket is sealed with RTV
which may still hold the element after the screws are
removed.
5. Clean RTV residue from the mating surface
inside the oven, apply new high temperature
RTV to the heating element mounting bracket
and reverse procedure to install.
6. Check for proper operation.
BLOWER AND MOTOR
1. Take out the racks and rack supports.
2. Remove screws securing baffle panel and
remove the panel.
8. Check for proper operation.
Alternate Access
If the heating element is not
inside the oven cavity, and access to the left side
panel and/or the top panel is available, this alternate
removal method may be used.
NOTE: On stacked ovens, if the bottom oven is
being serviced and the heating element to replace is
on the right side, the ovens must be unstacked to
access the heating element terminals through the
top. Once unstacked, follow the removal procedure
below.
1. Perform steps 1 thru 4 under FRONT ACCESS.
2. If the element is on the left
A. Remove the left side panel and pull back
the insulation at the top to expose the
element terminals.
B. Remove the lead wires from the element
being replaced. Proceed to step 4.
3. If the element is on the right
removing easily from
side:
side:
3. If replacing:
A. Blower Only
hub and using a bearing puller, remove
blower from motor shaft.
- Loosen set screws on blower
F25105 (Rev. A, October 2007) Page 10 of 60
FULL SIZE ELECTRIC CONVECTION OVEN - REMOVAL AND REPLACEMENT OF PARTS
1) Reverse procedure to install and
adjust blower position as outlined
under BLOWER ADJUSTMENT in
SERVICE PROCEDURES AND
ADJUSTMENTS.
B. Motor
4. Remove the nuts that secure the motor
mounting plate to the rear wall.
- perform step 3A and continue
procedure.
10. 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
viewed from the shaft end.
when
5. Place a piece of cardboard on the bottom of the
oven cavity to protect its surface from any
damage during motor assembly removal.
6. Pull the motor assembly into the oven cavity
and place it on the cardboard.
7. Remove the junction box cover from the motor,
disconnect lead wires and remove the conduit.
8. Remove motor mounting bolts and flat washers
then lift the motor from the mounting plate.
9. Position the replacement motor on the motor
mounting plate and install mounting bolts and
washers. Hand tighten mounting bolts only.
11. Slide blower onto motor shaft until hub is flush
with end of shaft then tighten set screws.
12. Adjust motor position until blower is parallel to
motor mounting plate as outlined under
BLOWER ADJUSTMENT in SERVICE
PROCEDURES AND ADJUSTMENTS.
13. Position motor mounting plate on the rear wall
and secure with nuts and washers.
14. Replace the baffle panel.
15. Remove cardboard from the bottom of the oven
cavity.
16. Check oven for proper operation then replace
rack guides and racks.
DOOR SWITCH
1. Remove the top front cover as outlined under
COVERS AND PANELS.
2. Disconnect the lead wires to the door switch.
3. Remove the switch.
F25105 (Rev. A, October 2007)Page 11 of 60
FULL SIZE ELECTRIC CONVECTION OVEN - REMOVAL AND REPLACEMENT OF PARTS
4. Reverse procedure to install the replacement
switch and check for proper adjustment as
outlined under DOOR SWITCH ADJUSTMENT
in SERVICE PROCEDURES AND
ADJUSTMENTS.
DOOR WINDOW
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.
1. Remove the screws at the top and bottom of
door.
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:
5. Reverse procedure to install the replacement
window.
OVEN DOORS AND BEARINGS
(INDEPENDENT DOORS)
1. Remove the top front cover and bottom front
cover as outlined under COVERS AND
PANELS.
2. Remove the door switch lever.
F25105 (Rev. A, October 2007) Page 12 of 60
FULL SIZE ELECTRIC CONVECTION OVEN - REMOVAL AND REPLACEMENT OF PARTS
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.
8. Reverse procedure to install door assembly and
check for proper adjustment as outlined under
DOOR ADJUSTMENT and DOOR SWITCH
ADJUSTMENT in SERVICE PROCEDURES
AND ADJUSTMENTS.
OVEN DOORS
(SIMULTANEOUS DOORS)
Assembly Removal
1. Remove the top front cover and bottom front
cover as outlined under COVERS AND
PANELS.
2. Remove the door switch lever.
NOTE: The door assembly is heavy and will drop
down once the last screw is removed. If removing
door assembly with-out assistance, use caution.
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.
3. Remove the top bearing retainers and top
bearings.
4. Remove the lower door seal strip to expose the
mounting screws of the door assembly.
A. Remove the two (2) lower sill bolts by the
lower door shaft and the four (4)
counter-sunk screws from the lower sill.
C. If replacing the bottom bearing, remove it
from the door shaft or the lower sill
opening.
F25105 (Rev. A, October 2007)Page 13 of 60
FULL SIZE ELECTRIC CONVECTION OVEN - REMOVAL AND REPLACEMENT OF PARTS
NOTE: The door assembly is heavy and will drop
down once the last screw is removed. If removing
door assembly with-out assistance, use caution.
5. Lift up on the door assembly and swing the right
side out then move the assembly to the left to
clear the slots in the upper door sill.
6. Lay the door assembly on a flat cushioned
surface for disassembly.
7. Reverse procedure to install door assembly and
check for proper adjustment as outlined under
DOOR ADJUSTMENT, DOOR CHAIN
ADJUSTMENT (SIMULTANEOUS DOORS)
and DOOR SWITCH ADJUSTMENT in
SERVICE PROCEDURES AND
ADJUSTMENTS.
Disassembly
1. Remove the door assembly as outlined in
OVEN DOORS (SIMULTANEOUS) under
ASSEMBLY REMOVAL.
2. Remove the door chain by loosening one of the
turnbuckles.
3. Loosen the set screw on the sprocket of door
being replaced.
ROLLER LATCH ASSEMBLY
(INDEPENDENT DOORS)
NOTE: For units with serial number starting with 48
made after 8/12/07 and serial number starting with
54 made after 8/26/07.
1. Remove the screws that attach roller latch
assembly to door.
4. Drive out the spirol pin from the sprocket of door
being replaced.
5. Remove the door from lower sill bearings and
sprocket.
A. Door assembly parts are now accessible
for inspection and/or replacement if
necessary.
2. Reverse procedure to install.
DOOR CATCH ROLLER
ASSEMBLY
(INDEPENDENT DOORS)
NOTE: For units with serial number starting with 48
made before 8/13/07 and serial number starting with
54 made before 8/27/07.
1. Remove the top front cover as outlined under
COVERS AND PANELS.
2. Remove the catch roller assembly.
6. Reverse procedure to re-assemble the door
assembly parts and check for proper adjustment
as outlined under DOOR CHAIN ADJUSTMENT
(SIMULTANEOUS DOORS) in SERVICE
PROCEDURES AND ADJUSTMENTS.
F25105 (Rev. A, October 2007) Page 14 of 60
FULL SIZE ELECTRIC CONVECTION OVEN - REMOVAL AND REPLACEMENT OF PARTS
3. Reverse procedure to install.
4. Adjust the catch roller as outlined under DOOR
CATCH (ROLLER) ADJUSTMENT
(INDEPENDENT DOORS) in SERVICE
PROCEDURES AND ADJUSTMENTS.
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.
5. Reverse the procedure to install.
6. Adjust the thermostat as outlined under
MECHANICAL (KX) THERMOSTAT
CALIBRATION in SERVICE PROCEDURES
AND ADJUSTMENTS.
HIGH LIMIT THERMOSTAT
1. Take out racks from the oven.
2. Remove the high limit thermostat
cover/mounting plate from inside the oven
cavity at the top.
MECHANICAL (KX)
THERMOSTAT
1. Remove the racks and right rack support.
2. Remove the thermostat knob and mounting
screws from the control panel and then remove
the control panel.
3. Remove the probe guard from the oven cavity
wall.
3. Disconnect lead wires from high limit thermostat
then remove high limit thermostat from
cover/mounting plate.
NOTE: When installing probe guard, the probe
should not extend beyond the guard.
4. Remove the thermostat bulb from the oven
cavity by pushing it through the oven wall and
into the control panel area.
F25105 (Rev. A, October 2007)Page 15 of 60
FULL SIZE ELECTRIC CONVECTION OVEN - REMOVAL AND REPLACEMENT OF PARTS
NOTE: Remove the old RTV sealer from the cover
and mating surfaces inside the oven cavity and apply
new high temperature RTV sealer before installing.
4. Reverse procedure to install.
INTERIOR LIGHTS
Lamp
1. Remove the racks.
2. Unscrew the glass lens for the light being
replaced then unscrew the bulb.
8. Check for proper operation.
COOLING FAN
1. Remove the right side panel as outlined under
COVERS AND PANELS.
NOTE: If right side panel is not accessible, this
component can be serviced by removing the control
panel as outlined under COVERS AND PANELS.
2. Disconnect the lead wires to the fan motor by
removing wire nuts.
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.
3. Replace bulb then reverse the procedure to
install.
Lamp Assembly
1. Remove the lens and bulb.
2. Remove the springs from the retaining tabs (2
places) on the socket.
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.
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
outside 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.
F25105 (Rev. A, October 2007) Page 16 of 60
FULL SIZE ELECTRIC CONVECTION OVENS - SERVICE PROCEDURES AND ADJUSTMENTS
SERVICE PROCEDURES 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. 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 power switch to ON.
3. Set the temperature control dial to 350 °F.
4. Allow the oven temperature to stabilize
(normally 3 cycles).
5. Record the temperature at which the Heat lamp
goes OFF and comes ON for at least two
complete heating cycles.
6. Calculate the differential by subtracting the
temperature indicated when the lamp goes out
from the temperature indicated when the lamp
comes on.
A. The differential calculated should be less
than 20 °F.
B. If the average temperature is more
10 °F from the dial setting, the thermostat
calibration must
1) Loosen the temperature control knob
set screw and remove the knob from
the stem.
2) Loosen temperature control mounting
screws only enough to rotate the
control.
a. Place thumb and forefinger on
b. Center the stem in the opening
be adjusted.
the head of the mounting screws,
apply pressure and slightly rotate
the screw heads (body of control)
in the slot. Rotate clockwise
increase temperature and
counterclockwise
and re-tighten the temperature
control mounting screws.
to decrease.
than
to
1) If the differential is 20 °F or less
temperature control circuit is
functioning properly.
a. Proceed to step 7.
2) If the differential is more
a. Check the temperature probe as
outlined under "TEMPERATURE
PROBE TEST (SOLID STATE
CONTROL)".
b. If the probe is functioning
properly then temperature control
is malfunctioning.
a) Install a replacement
temperature control and
check calibration.
7. 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.
A. If the average temperature is 10 °F or
, from the dial setting, the thermostat is
less
properly calibrated.
than 20 °F:
, the
c. Replace knob and re-tighten set
screw.
d. Rotate the knob to the lowest
temperature setting then back to
350°F.
e. Repeat the average temperature
calculation in step 7.
F25105 (Rev. A, October 2007)Page 17 of 60
FULL SIZE ELECTRIC CONVECTION OVENS - SERVICE PROCEDURES AND ADJUSTMENTS
NOTE: Allow the oven to cycle at
least two times between
adjustments before performing
the calculation.
a) If the average temperature
still differs more
from the dial setting, adjust
the thermostat calibration
until the average
temperature is within
tolerance.
C. If the above adjustment cannot be
obtained:
1) Turn the power switch OFF.
2) Replace the temperature control and
check calibration.
than 10 °F
7. Calculate the average temperature by adding
the temperature indicated when the heat lamp
goes out to the temperature indicated when the
heat lamp comes on and dividing this answer by
2.
A. If the average temperature is 15 EF or less
from the dial setting, the thermostat is
properly calibrated.
B. If the average temperature is more
15 EF of the dial setting, the thermostat
calibration must
1) Remove the thermostat knob.
2) Hold the thermostat shaft and turn the
inner set screw clockwise
temperature or counterclockwise
increase temperature (¼ turn = 35EF).
be adjusted.
than
to decrease
to
MECHANICAL (KX)
THERMOSTAT CALIBRATION
1. Place a thermocouple in the geometric center of
the oven cavity.
2. Set the power switch to ON.
3. Set the thermostat dial to 350 °F.
4. Allow the oven temperature to stabilize
(normally 3 cycles).
5. Record the temperature when the thermostat
cycles OFF and ON for at least three complete
cycles.
6. Calculate the differential by subtracting the
temperature indicated when heat lamp goes out
from temperature indicated when heat lamp
comes on.
A. The differential calculated should be less
than 30EF.
1) If the differential is 30 °F or less
thermostat is functioning properly.
a. Proceed to step 7.
2) If the differential is more
the thermostat is malfunctioning.
a. Install a replacement thermostat
and check calibration.
than 30 EF,
, the
8. Replace the knob and verify the setting is still at
350°F.
9. Repeat step 7 until the average temperature is
within tolerance.
NOTE: Allow the oven to cycle at least two times
between adjustments before performing the
calculation.
A. After the final adjustment is made and the
average temperature is within tolerance,
remove the knob and apply a nonpermanent type sealer around the head of
the set screw.
10. If the above adjustment cannot be obtained:
F25105 (Rev. A, October 2007) Page 18 of 60
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