Shel Lab SMO14-2 User Manual

Installation and

Operation Manual

SMO14-2 SMO28-2 SMO28G-2

Previously Designated:

FX14-2 FX28-2

SMO Forced Air Ovens 230 Voltage

SMO Forced Air Ovens 230 Voltage

Previously Designated FX Forced Air Ovens

Installation and Operation Manual
Part Number (Manual): 4861581
Revision: June 3, 2015

Pictured on Cover: SMO14-2 and SMO28-2

Note: The SMO28G-2 ships with two wire shelves typically used in curing applications. The

SMO28G-2 is identical to the SMO28-2 in all other respects.

These units are TÜV CUE listed as forced air ovens for professional, industrial, or educational use
where the preparation or testing of materials is done at an ambient air pressure range of 22.14 –

31.3 inHg (75 – 106 kPa) and no flammable, volatile, or combustible materials are being heated.
These units have been tested to the following requirements:
CAN/CSA C22.2 No. 61010-1:2012

CAN/CSA C22.2 No. 61010-2-010 + R:2009
UL 61010A-2-010:2002
UL 61010-1:2012
EN 61010-1:2010
EN 61010-2-010:2003

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TABLE OF CONTENTS

INTRODUCTION ........................................................................................................................................... 4

General Safety Considerations ................................................................................................................. 4

Engineering Improvements ....................................................................................................................... 5

Contacting Assistance ............................................................................................................................... 5

Temperature Reference Sensor Device ................................................................................................... 5

RECEIVING YOUR UNIT .............................................................................................................................. 6

Inspecting the Shipment ............................................................................................................................ 6

Orientation ................................................................................................................................................. 7

Recording Data Plate Information ........................................................................................................... 10

INSTALLATION .......................................................................................................................................... 11

Location ................................................................................................................................................... 11

Power Source Requirements .................................................................................................................. 11

Power Feed Wiring .................................................................................................................................. 12

Lifting and Handling ................................................................................................................................ 12

Leveling ................................................................................................................................................... 12

Initial Cleaning ......................................................................................................................................... 13

Shelving Installation ................................................................................................................................ 13

GRAPHIC SYMBOLS ................................................................................................................................. 14

CONTROL PANEL OVERVIEW ................................................................................................................. 16

OPERATION ............................................................................................................................................... 18

Operating Precautions ............................................................................................................................ 18

Theory of Operation ................................................................................................................................ 19

Preparing the Oven ................................................................................................................................. 21

Prepare for First Use Burn-In .................................................................................................................. 21

Set the Oven Temperature Set Point ...................................................................................................... 22

Burn-In ..................................................................................................................................................... 23

Temperature Display Accuracy Verification ............................................................................................ 23

Setting the Over Temperature Limit ........................................................................................................ 25

Setting the Timer ..................................................................................................................................... 26

Drying Racks and other Accessories ...................................................................................................... 27

Launch a Heating Profile ......................................................................................................................... 28

USER MAINTENANCE ............................................................................................................................... 29

Cleaning and Disinfecting ....................................................................................................................... 29

Calibrating the Temperature Display....................................................................................................... 30

Door Components ................................................................................................................................... 33

Electrical Components ............................................................................................................................ 33

UNIT SPECIFICATIONS ............................................................................................................................. 34

Weight ..................................................................................................................................................... 34

Dimensions .............................................................................................................................................. 34

Capacity .................................................................................................................................................. 34

Shelf Capacity by Weight ........................................................................................................................ 35

Temperature ............................................................................................................................................ 35

Power ...................................................................................................................................................... 35

PARTS LIST ............................................................................................................................................... 36

Ordering .................................................................................................................................................. 36

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INTRODUCTION

Thank you for purchasing a Sheldon Manufacturing SMO forced air oven. We know that in today’s
competitive marketplace, customers have many choices when it comes to constant temperature
equipment. We appreciate you choosing ours. Our continued reputation as a leading laboratory
product manufacturer rests with your satisfaction. Sheldon Manufacturing, Inc. stands behind our
products, and we will be here if you need us.

These ovens are intended for professional, industrial, and educational applications. The ovens are
not intended for use at hazardous or household locations. SMO forced-air ovens are engineered for
constant temperature forced-air drying, curing, and baking applications

GENERAL SAFETY CONSIDERATIONS

Note: Failure to follow the guidelines and instructions in this manual may create a protection

impairment by disabling or interfering with the unit’s safety features. This can result in injury
or death.

Before placing the oven in operation read this entire manual carefully to understand how to install,
operate, and maintain the oven in a safe manner. Keep this manual available for use by all oven
operators. Ensure that all operators are given appropriate training before the oven begins
operation.

Your oven and its recommended accessories have been designed and tested to meet strict safety
requirements. For continued safe operation of your oven, always follow basic safety precautions
including:

 Follow any local or regional ordinances in your area regarding the use of this unit.
 Only use the oven for its intended range of applications.
 Use only approved accessories. Do not modify system components. Any alterations or

modifications to your oven may be dangerous and will void your warranty.

 Always hardwire the unit’s power feed to an earth-grounded electrical source that conforms

to national and local electrical codes. If the unit is not grounded, parts such as, knobs and
controls may conduct electricity and cause serious injury.

 Avoid damaging the power feed. Do not bend it excessively, step on it, place heavy objects

on it. A damaged power feed can easily become a shock or fire hazard. Never use a power
feed after it has been damaged.

 Position the equipment so the end-user can quickly and easily disconnect or uncouple the

power feed in the event of an emergency.

 Do not attempt to move the unit while in operation or before the unit has cooled.

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INTRODUCTION (CONTINUED)

ENGINEERING IMPROVEMENTS

Sheldon Manufacturing, Inc. continually improves all of its products. As a result, engineering
changes and improvements are made from time to time. Therefore, some changes, modifications,
and improvements may not be covered in this manual. If your unit’s operating characteristics or
appearance differs from those described in this manual, please contact your Shel Lab dealer or
customer service representative for assistance.

CONTACTING ASSISTANCE

If you are unable to resolve a technical issue with your oven, please contact Sheldon Technical
Support. Phone hours for Sheldon Technical Support are 6am – 4:30pm Pacific Coast Time (west
coast of the United States, UTC -8). Please have the following information ready when calling or
emailing Technical Support: the model number and the serial number (see page 10).

EMAIL: [e-mail] PHONE: [phone] extension 4, or [phone] FAX: (503)
640-1366

Sheldon Manufacturing INC.
P.O. Box 627
Cornelius, OR 97113

TEMPERATURE REFERENCE SENSOR DEVICE

The oven does not come with a temperature reference device. A reference sensor device must be
purchased separately for performing accuracy verifications or calibrations of the oven temperature
display.

The reference device must be accurate to at least 0.1°C, and should be regularly calibrated,
preferably by a third party.

For best results, use a digital device with a thermocouple or other remote reading probe. Remote
readings avoid oven chamber door openings during verification and calibration procedures. This
avoids subsequent waits for the chamber temperature to re-stabilize. Select a probe suitable for the
application temperature you will be calibrating or verifying the display accuracy at.

Alcohol thermometers are insufficient for conducting accurate verifications and calibrations. Do not use a
mercury thermometer. Never place a mercury thermometer in the oven chamber.

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Model

Shelves

Shelf Clips

Leveling Feet

SMO14-2

3

12

4

SMO28-2

6

24

4

Model

Shelves

Shelf Clips

Leveling Feet

SMO28G-2

2 8 4

RECEIVING YOUR UNIT

Before leaving the factory, all SMO ovens are packaged in high-quality shipping materials to
provide protection from transportation-related damage. When a unit departs our factory, safe
delivery becomes the responsibility of the carrier. Damage sustained during transit is not covered
by the manufacturing defect warranty.

This makes it important that you inspect your oven for concealed loss or damage to its interior and
exterior when receiving it. If you find any damage to the unit, follow the carrier’s procedure for

claiming damage or loss.

The orientation photos on the immediately following pages may serve as useful references when
inspecting the oven.

Carefully check all packaging before discarding. Save the shipping carton until you are certain that
the unit and its accessories function properly.

INSPECTING THE SHIPMENT

Carefully inspect the shipping carton for damage. Report any damage to the carrier service that
delivered the SMO oven. If the carton is not damaged, open the carton and remove the contents.
The unit should come with an Installation and Operation Manual and a Certificate of Compliance.

Verify that the correct number of components have been included.

Included components:

Figure 1: Accessory Components

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Power Panel (Back)

Permanent Connect Wire Braid
14 gauge, 6 inches (15 cm)

Control Panel

Damper with Slider

Damper with Slider

Main Temperature
and OTL Sensor

Door Latch

Door Latch

Shelf Standard
Rail

Oven Chamber

Chamber Door
Handle

Chamber
Liner Gasket

Door Liner
Gasket

RECEIVING YOUR UNIT (CONTINUED)

ORIENTATION

Figure 2: SMO28-2

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Power Panel (Back)

Permanent Connect Wire Braid
14 gauge, 6 inches (15 cm)

Control Panel

Damper with Slider

Damper with Slider

Main Temperature
and OTL Sensor

Door Latch

Shelf Standard
Rail

Oven Chamber

Chamber
Door Handle

Chamber
Liner Gasket

Door Liner
Gasket

RECEIVING YOUR UNIT (CONTINUED)

Figure 3: SMO28G-2

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Control Panel

Main Temperature
and OTL Sensor

Shelf Standard
Rail

Chamber
Door Handle
Damper with Slider

Damper with Slider

Oven Chamber

Power Panel
(Back)

Permanent
Connect Wire
Braid 14 gauge, 6
inches (15 cm)

Door Liner
Gasket

Chamber Liner
Gasket

RECEIVING YOUR UNIT (CONTINUED)

Figure 4: SMO14-2

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Model Number

Serial Number

RECEIVING YOUR UNIT (CONTINUED)

RECORDING DATA PLATE INFORMATION

Locate the data plate on the back of the oven below the power braid inlet. The data plate contains
the oven model number and serial number. Technical support and your distributor will need these
numbers in order to assist you in the future.

Date Plate Information

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INSTALLATION

Installation of the unit requires permanent connect wiring (commonly known as hardwiring) that
must be performed by a qualified electrical technician. All other steps can be performed by the
end-user.

This oven is intended for use indoors, at room temperatures between 15C and 40C (59F and

104F), at no greater than 80% Relative Humidity (at 25C / 77F). Allow a minimum of 12 inches
(30cm) between the oven and any walls or partitions, as well as 12 inches (30cm) of vertical

headspace clearance above the top of the oven for unobstructed airflow and cooling.

Operating the unit outside of these conditions may adversely affect its temperature range
and stability. For conditions outside of those listed above, please contact your distributor to

explore other oven options suited to your laboratory or production environment.

LOCATION

When selecting a location to install the oven, consider all environmental conditions that can impact
the temperature range, uniformity, and stability of the unit. For example:

 Other ovens, autoclaves, and any device that produces significant radiant heat
 Heating and cooling ducts, or other sources of fast moving air currents
 High-traffic areas
 Direct sunlight

POWER SOURCE REQUIREMENTS

When selecting a location for the oven, check that each of the following requirements are satisfied:

 The oven must be positioned so that all operators have access to the power feed

disconnect in case of emergencies.

o The Disconnect must be in close proximity to the equipment and within easy reach

of the operator.

o The Disconnect must be marked as the disconnecting device for the equipment.

 The power source must conform to all national and local electrical codes.
 The power source must be earth grounded.
 The power source voltage and ampere must match the power requirements listed on the

oven data plate (located on the back of the unit, beneath the power feed inlet).

o These ovens are intended for 230 volt, 50/60 Hz applications at the following

amperages: SMO14-2 12 Amps; SMO28-2 and SMO28G-2 20 Amps.

Continued on next page

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INSTALLATION (CONTINUED)

 Supplied voltage must not vary more than 10% from the data plate rating. Damage to

the oven may result if supplied voltage varies more than 10%.

 Use a separate circuit to prevent loss of the unit due to overloading or circuit failure.
 A switch or circuit-breaker must be used in the building installation to protect against

overcurrent conditions.

o The required circuit-breakers are: SMO14-2 15A and SMO28-2 SMO28G-2 30A.

POWER FEED WIRING

The oven comes provided with an integral 6 inch (15 cm) wire braid of two 14 gauge high­temperature (300°C) hot wires and a 14 gauge earth ground.

The wires for power source connection should be in accordance with the following:
SMO14-2: Green/Yellow – Earth; Red – Hot; Black – Hot.
SMO28-2 SMO28G-2: Green/Yellow – Earth; Black – Hot; Black – Hot.

The oven must be grounded using the protective conductor terminal (green with yellow stripe
wire). Do not remove the protective conductor (earth connection). Removing the protective
conductor will negate the oven protections against potentially dangerous electric shocks and create
a possible fire hazard.

LIFTING AND HANDLING

The oven is heavy. Use appropriate lifting devices that are sufficiently rated for these loads. Follow
these guidelines when lifting the oven:

 Lift the oven only from its bottom surface.
 Doors, handles, and knobs are not adequate for lifting or stabilization.
 Restrain the oven completely while lifting or transporting so it cannot tip.
 Remove all moving parts, such as shelves and trays, and lock doors in the closed position

during transfers to prevent shifting and damage.

LEVELING

The oven must be level and stable for safe operation. Each SMO oven ships with four leveling feet.
Insert one leveling foot into each of the four holes in the bottom corners of the oven. Stand the oven
upright. Then, adjust the foot at each corner until the oven stands level and solid without rocking.
To raise a foot, turn it in a counterclockwise direction; to lower a foot, turn it in a clockwise direction.

To prevent damage when moving the oven, turn each of the four leveling feet completely clockwise.

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INSTALLATION (CONTINUED)

INITIAL CLEANING

The unit was cleaned at the factory, but not sterilized. Additionally, it may have been exposed to
contaminants en route during shipping. See the Cleaning and Disinfecting topic in the User
Maintenance section (page 29) for more information on how to clean and disinfect the oven
chamber.

Remove all wrappings and coverings from shelving prior to cleaning and installation.

SHELVING INSTALLATION

Perform the following steps to install the SMO shelves:

1. Install the shelf clips in the slots of the shelf standard rails located on the sides and rear of
the chamber interior.

a. Squeeze each clip.
b. Insert the top tab first, then the bottom tab using a rocking motion.

2. Hang the shelves from the clips.

Figure 5: Shelving Installed in Shelf Standard Rails

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Symbol

Definition

Indicates that you should consult your service manual for further instructions.
Indique que l'opérateur doit consulter le manuel d'utilisation pour y trouver les instructions

complémentaires.

Indicates Temperature
Repère température

Indicates the Over Temperature Limit system
Indique le système de dépassement de temperature

Indicates AC Power
Repère le courant alternative

Indicates ( I ) ON and ( O ) OFF
I repère de la position MARCHE de l'interrupteur d'alimentation
O repère de la position ARRÊT de l'interrupteur d'alimentation

Indicates protective earth ground
Repère terre électrique

Indicates UP and DOWN respectively
Touches de déplacements respectifs vers le HAUT et le BA

Indicates a Manually Adjustable control
Indique un bouton réglable manuellement

Indicates a Potential Shock Hazard
Signale danger électrique

Indicates the unit should be recycled (Not disposed of in land-fill)
Indique l’appareil doit être recyclé (Ne pas jeter dans une décharge)

GRAPHIC SYMBOLS

The oven is provided with multiple graphic symbols on its exterior. The symbols identify hazards
and the functions of the adjustable components, as well as important notes in the user manual.

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Symbol

Definition

Indicates the timer
Indique le minuterie

Start or Stop the Timer
Lancer ou arrêter le minuteur

Reset the Timer
Réinitialisation de la Minuterie

Indicates: Caution hot surface
Indique: Avertissement symbole de surface chaude

GRAPHIC SYMBOLS (CONTINUED)

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CONTROL PANEL OVERVIEW

Figure 6: Control Panel

Power Switch

The green Power Switch controls overall power to the oven. When in the ON ( I ) position the switch
illuminates and the oven will heat to and maintain the currently programed temperature set point.

Timer Switch

The black Timer Switch controls power to the timer system. When this switch is in the ON position
the SET TIMER display will illuminate, and the oven can run a timed steady-state heating profile at
the current temperature set point. The oven will not heat while the Timer system is on unless a
profile is running.

Over Temperature Limit Control (OTL)

This graduated dial sets the temperature limit for the Over Temperature Limit system. The OTL is
an independent mechanical heating cutoff that prevents unchecked heating of the oven in the event
of a failure of the main temperature controller system. For more details, please see the explanation
of the Over Temperature Limit System on page 20 in the Theory of Operation entry.

OTL Light

Marked OVER TEMP ACTIVATED, this light illuminates whenever the OTL System is routing
power away from the heating elements. Under normal operating conditions this light should never
illuminate.

Timer Display and Control Pad

The SET TIMER display can show the duration of the currently programed heating profile; or a
flashing duration adjustment mode; or the countdown of a running profile to 0.

The “//” RESET button is used to place the Timer display in its adjustable duration mode, and then
to scroll through the duration time parameters.

The black SET TIMER arrow buttons adjust the heating profile duration time parameters when the
display is in its blinking adjustment mode.

The “T” START/STOP timer button launches a heating profile or pauses a running profile.

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CONTROL PANEL (OVERVIEW)

Main Temperature Display and Control

Marked SET TEMPERATURE, this display shows the current oven chamber air temperature
accurate to within +0.1C. The display can also show an adjustable temperature set point in the
display’s set point mode, as well as an adjustable offset while in calibration mode.

The arrow buttons can be used to adjust the temperature set point or place the unit in its calibration
mode, and then enter a calibration offset value.

Heating Activated Light

The green pilot light located beneath the label HEATING ACTIVATED illuminates whenever the
workspace oven heating elements are powered and warming the oven. The oven uses measured
pulses to achieve and maintain the temperature set point.

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OPERATION

OPERATING PRECAUTIONS

Warning: The SMO oven is not an explosion-proof unit! The oven is not designed to safely contain combustible gasses. Do

not place explosive, combustible, or flammable materials into the chamber.

1. The bottom surface of the chamber should not be used as a work surface

2. Do not operate the oven in an environment with noxious fumes.

3. The SMO oven is provided with dampered intake and exhaust vents. For safe and efficient
oven operation follow these precautions:

a. In normal heating the dampers are closed.
b. Outgassed byproducts maybe hazardous to or noxious for operating personal.

If either is the case, oven exhaust should be positively ventilated to a location
outside workspace in accordance with national and local regulations.

4. Do not place sealed or filled containers in the oven.

5. Do not place mercury thermometers in the oven.

6. The SMO oven is not designed for use in Class I, II, or III locations as defined by the US
National Electric Code.

Warning: The vent dampers may be hot to the touch. These areas are marked with Hot Surface labels. Proper PPE should be

employed to minimize risk to burn.

Avertissement:Les clapets d'aération peuvent être chauds au toucher. Ces zones sont marqués avec des étiquettes de

Surface chaude. Les EPI approprié devraient être employée pour réduire au minimum le risque de brûler.

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OPERATION (CONTINUED)

THEORY OF OPERATION

Heating

When powered, the SMO oven chamber will heat to and then maintain the currently programed
temperature set point. The oven comes from the factory with a temperature set point of 150°C. The
set point may be adjusted by the end-user using the Set Temperature controls.

Heating is controlled by a microprocessor controller board that stores the temperature set point.
The microprocessor senses the chamber air temperature via a solid-state probe located in the
airstream on the back wall of the chamber. When the processor detects that the chamber
temperature has dropped below the temperature set point, it pulses power to a heating element in a
recirculation air duct space located above the oven chamber.

The processor employs proportional-integral-derivative analytical feedback-loop functions when
measuring and controlling the chamber air temperature levels. PID-controlled heating pulse
intensities and lengths are proportional to the difference between the measured chamber
temperature and the current set point. The frequency of pulses are derived from the rate of change
in the difference. The integral function slows the rate of pulses when the temperature nears the set
point to avoid overshooting.

SMO ovens rely on natural heat radiation for cooling.
When the oven is powered the chamber air temperature cannot go below the ambient room

temperature plus the internal waste heat of the oven. Waste heat is generated primarily by the
operation of the blower fan motor and the resulting air compression in the duct spaces. In practice
the temperature floor is ambient +15°C.

The oven depends on the operation of the blower fan to maintain temperature uniformity and
stability in the chamber.

Air Circulation

The oven continually circulates air internally while powered. Air is forced through vent holes at the
back of the chamber, blows across the shelf space to the front, and is then pulled upward into a
heating and recirculation air duct by the action of the blower fan.

The oven is provided with two dampener vents that may be opened or closed using dampener
slides located on the oven exterior. SMO forced air ovens must be run with the dampeners

closed in order to achieve the stated chamber temperature uniformity and stability.

The dampeners are intended to speed drying or evaporation rates after the heated portion of an
application is complete. Opening the dampener vents while the oven is running may speed the rate
of material drying, dependent on the nature of your application. However, running the oven with the
dampeners open introduces cool air into the chamber while allowing heated air to exit. This may
impact the temperature uniformity and stability of the chamber, and lower the operational
temperature ceiling.

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OPERATION (CONTINUED)

Timed Heating Profile

The oven is provided with a Timer subsystem that can run the oven in a steady-state heating profile
at the current temperature set point from 1 minute in length up to 99 hours, 59 minutes. The oven
still requires time to come to temperature when running a heating profile. Launching a profile with
the temperature set point set to 150°C immediately after turning on the oven will result in the first 24
minutes of the profile being spent with the chamber rising from room temperature to 150°C.

When the Timer system is on the oven will not heat unless a profile is running.

The Over Temperature Limit System (OTL)

When set, the OTL heating cutoff system prevents runaway heating in the event of a failure of the
microprocessor controller or its thermometer probe. The OTL operates independently of the
microprocessor and is provided with a separate, hydrostatic temperature sensor probe located in
the oven chamber. In the event the temperature of the chamber exceeds the current OTL setting,
the OTL routes power away from the heating elements. The Over Temperature Limit is set by the
end-user, typically at approximately 1°C above the application temperature set point. Because of
its nature as a mechanical cutoff system and its lack of PID analytics, the OTL cannot deliver the
same degree of temperature stability and measurement precision as the digital display and
microprocessor.

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OPERATION (CONTINUED)

Note: Performing a temperature accuracy verification requires a suitable temperature reference

device. Please see the Temperature Reference Device entry on page 5 for the device
requirements.

PREPARING THE OVEN

Preform the following steps to prepare the oven for use after installing it in a new workspace environment.
Optional: If you will be performing a temperature display accuracy verification (page 23) Sheldon

Manufacturing recommends introducing the temperature probe of your temperature reference device into
the oven chamber now, prior to powering the oven. Doing so will save time when carrying out the
procedure. Please see step 1 of the verification procedure on page 24 for probe placement instructions.
The probe must be rated for at least 210ºC as it will be inside the chamber during the 200ºC First Use
Burn-In procedure.

1. Turn on the oven by placing the green main power switch in the ( I ) ON position.

2. Perform the following procedures:

a. Prepare for First Use Burn-In page 21
b. Set the Oven Temperature Set Point page 22
c. Burn-In page 23
d. Set the Oven Temperature Set Point page 22*
e. Verify Temperature Accuracy (Optional) page 23
f. Set the Over Temperature Limit page 28

*This time set the temperature to that of your application.

PREPARE FOR FIRST USE BURN-IN

If the oven is being run for the first time out of the box, perform the 3 steps below followed by the
Burn-In procedure to burn off the protective oil coating from the oven heating element. This
prevents smoking during normal operations above 150˚C.

1. Open both dampener vents all the way.

2. Positively vent the oven exhaust outside of its workspace environment during the Burn-In
Procedure. The procedure will produce light smoking

3. Use the Set the Temperature Set Point procedure on the next page to set the oven to run
at 200C°.

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Set Temperature

Note: The oven should come from the factory with the OTL dial set to max.

1. Turn the Over Temperature Limit (OTL) control dial clockwise to the
maximum position indicated by the largest dot, if not already set to max.

a. This prevents the Over Temperature Limit system from

interfering with this procedure, as well as the first use burn-in.

2. Press and release either of the Set Temperature arrows to activate the
temperature set point adjustment mode.

a. The temperature display will briefly flash the letters “SP” to

indicate the Set Point is about to be displayed.

b. The Set Temperature digital display will then show the

flashing, adjustable temperature set point.

Set Temperature

3. Use the Up or the Down arrow key to adjust the set point.

Note: The display will automatically exit the adjustment mode after 5

seconds of inactivity, with the last shown set point value saved.

Set Temperature

New Set Point

4. Wait 5 seconds after entering the set point.

a. The display will stop flashing, and the set point is now saved in

the controller.

b. The oven will now automatically heat or passively cool to

match your set point.

c. The display will revert to showing the current chamber air

temperature.

Set Temperature

Heating to Set Point

See the Setting the Over Temperature Limit procedure on page 25 for how to
set the OTL heating cutoff system once the oven has stabilized at your application
temperature set point.

Leave the OTL dial set its maximum clockwise position if you are preparing to run
the Burn-In procedure.

OPERATION (CONTINUED)

SET THE OVEN TEMPERATURE SET POINT

Adjust the oven temperature set point to that of your application. If preparing to perform the first-use
burn-in procedure set the oven to 200°C.

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End of Procedure

Figure 7: Dampener Closed

OPERATION (CONTINUED)

BURN-IN

1. Once the oven chamber has reached 200°C allow it to run for a minimum of 1 hour.

2. Continue to run the oven at 200°C if it is still producing light smoking from the vent holes at
the back of the chamber.

3. The procedure is complete once the light smoking stops.

4. Once the burn-in is complete set the oven temperature to your process or application set
point. This prepares the oven for use, as well as the optional temperature display accuracy
verification.

TEMPERATURE DISPLAY ACCURACY VERIFICATION

Note: Performing an accuracy verification of the oven temperature display requires a suitable
temperature reference device. Please see the Temperature Reference Device entry on page 5 for
the device requirements.

Optional: The oven was calibrated at the factory at 150ºC. A verification process may be carried
out to verify the accuracy of the SMO temperature display when preparing the oven for use, if
required by your laboratory or production protocol.

If a difference between the actual and displayed temperature is discovered, perform a temperature
calibration (please see the Calibrate Temperature Display procedure on page 30 in the User
Maintenance section).

Prior to a verification, the oven should be run at its verification temperature for at least 1 hour in
order to allow the chamber to stabilize with no fluctuations greater than ±0.1°C. The chamber is
considered thermally stable when no fluctuations have been detected with the verification reference
device for a minimum of 30 minutes. Failure to wait for stabilization will result in an inaccurate
verification. After the chamber has stabilized a wait of 15 minutes without a change of ±0.1°C
should suffice for it re-stabilize after brief disruptions such as, short door openings.

Both dampeners must be fully closed during the verification procedure and the proceeding warmup.
Failure to do so will result in an inaccurate temperature reading.

Continued on next page

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Verifying the Temperature Display Accuracy

1. Place the temperature sensor of the reference device inside the oven as
close as possible to the geometric center of the chamber.

a. Probes may be introduced through the chamber door space,

and the door closed over probe wires.

Note: A thermocouple sensor probe sleeve may be taped to the shelving, as
long as the exposed copper end is 2 inches (5cm) away from the shelf. An
exposed sensor probe in direct contact with the shelving may experience heat
sinking, which can result in an inaccurate temperature reading.

2. Allow the chamber temperature to re-stabilize if the chamber door has
been opened during the past 15 minutes.

a. The reference device temperature reading should not change by

±0.1°C for at least 15 minutes after a significant disruption for the
oven to be considered re-stabilized.

3. Once the chamber temperature has stabilized, compare the reference
device and the oven display temperature readings.

a. If the readings are the same, or the difference between the

two (2) falls within the acceptable range of your protocol, the
display is accurately showing the oven chamber air
temperature.

b. The Temperature Verification procedure is now

complete.

Reference Device

Set Temperature



4. If there is a difference between the two readings, and that offset falls
outside your laboratory or production protocol’s acceptable range,
perform a temperature calibration to match the Set Temperature
display to the actual chamber. Please see page 30.

Reference Device

Set Temperature



OPERATION (CONTINUED)

End of procedure

24 | P a g e

Set The OTL Cutoff

Example

1. If you have not done so already, turn the Set Over Temperature Limit
control dial clockwise to the maximum position.

2. Turn the Over Temperature Limit control dial co unterclockwise until the
red Over Temp Limit Activated light illuminates.

3. Slowly turn the dial clockwise until the Over Temperature Limit
Activated light turns off. Stop turning the control.

4. Leave the OTL dial set slightly above the activation point.

a. The Over Temperature Limit is now set approximately 1˚C

above the current chamber temperature.

OPERATION (CONTINUED)

SETTING THE OVER TEMPERATURE LIMIT

This procedure sets the Over Temperature Limit heating cutoff to approximately 1˚C above the
current temperature set point.

Perform the steps below once the oven has been stabilized at your application temperature set
point for at least a 30 minutes.

The Over Temperature Limit System activates if the oven temperature exceeds the setting of the
OTL System. If the oven microprocessor controller has failed, or the OTL is set below your chosen
temperature set point, the OTL alarm indicator will turn on and off indefinitely as the OTL depowers
the heating elements whenever the temperature exceeds the cutoff limit. If this is happening, repeat
steps 1 - 3 to verify that the OTL is set above the temperature set point. Contact technical support
or your distributor if the OTL continues to activate.

End of procedure

25 | P a g e

Set Timer Duration

1. Turn on the Timer system by placing the black Timer switch in the
On ( I ) position.

a. The Timer Display will illuminate showing the previously

programed profile duration.

b. The oven will automatically cease heating.

Set Timer

1 Minute Profile

2. Press and hold the Rest button until the Timer Display begins to blink.

a. The display is now in its adjustable duration mode.
b. A decimal point will illuminated between the 2nd and 3rd

number parameters.

c. This indicates that Hours parameter is selected.

Set Timer

Note: If 5 seconds elapse with no activity on the Arrow Pad buttons the

Timer Display will exit the adjustment mode with the last entered time
values saved.

3. Use the Up or the Down arrow key to adjust the Hour parameter

to setting of 0 to 99.

Set Timer

1 Hour, 1 Minute

4. Press the Reset button to advance to the Tens of Minutes parameter.

a. The flashing decimal point will advance to between the third

and fourth numbers.

b. Advancing automatically saves the entered Hour parameter.

Set Timer

OPERATION (CONTINUED)

SETTING THE TIMER

This procedure enters a duration for a heating profile in the Timer system. The profile will run the
oven for the duration at the currently programed temperature set point.

Procedure continued on next page

26 | P a g e

Set Timer Duration (Continued)

5. Use the Up or the Down arrow key to adjust the Tens of Minutes
parameter.

Set Timer

1 Hour, 51 Minutes

6. Press the Reset button to advance to the Single Minutes parameter.

a. The flashing decimal point will advance to the right of the

fourth numeral.

b. Advancing automatically saves the entered Hour parameter.

Set Timer

7. Use the Up or the Down arrow key to adjust the Single Minutes
parameter.

Set Timer

1 Hour, 55 Minutes

8. Wait for 5 seconds after entering the Single Minutes parameter.

a. The display will exit adjustment mode.

b. The Single Minutes parameter, along with the previous two

parameter values are now saved.

Set Timer

OPERATION (CONTINUED)

End of procedure

DRYING RACKS AND OTHER ACCESSORIES

Make sure that any accessories used inside the oven chamber such as, drying racks, are suitable
for your application and will not suffer damage when brought to temperature. Always set the OTL
cutoff system to approximately 1°C above your application temperature set point in order to
safeguard accessories against over temperature events. The manufacturing defect warranty does
not cover damage caused by melted or otherwise overheated accessory items.

27 | P a g e

Launch the Heating Profile

1. The Timer switch must be in the ON ( I ) position just prior to
launching the profile.

Set Timer

1 Hour, 55 Minute Profile

2. Press the Start/Stop T button to launch the current profile.

a. The profile will launch and the TIMER ACTIVATED indicator

will illuminate.

b. The Timer Display will start counting down.

c. The oven will resume heating.

Set Timer

3. To pause a running profile, press the Start/Stop button.

a. The oven will cease heating until the profile is restarted, reset,

or the Timer system is turned off.

b. To restart the profile where it left off, press the Start/Stop

button again

Pause Profile

4. The oven will automatically cease heating upon reaching “00:00”.

a. To resume manual heating place the Timer Switch in the OFF

( O ) position.

- Or -

b. To launch another profile press the “//” Reset button and enter

a new profile, or allow the previous profile to reset
automatically after 5 seconds.

Set Timer

Profile Complete

OPERATION (CONTINUED)

LAUNCH A HEATING PROFILE

The oven can be run in a timed, steady-state heating profile at the currently selected temperature
set point. Allow the oven to come up to temperature prior to launching a profile. See the Setting

the Timer procedure on page 26 for how to set the length of the profile.

Note: While the Timer system is on the oven will not heat unless a profile is running.

28 | P a g e

End of procedure

USER MAINTENANCE

Warning: Prior to maintenance or service on this unit, disconnect the power feed from the power supply.

Avertissement: Avant d'effectuer toute maintenance ou entretien de cet appareil, débrancher le cordon secteur de la source

d'alimentation.

CLEANING AND DISINFECTING

If a hazardous material or substance has spilled in the oven, immediately initiate your site’s
Hazardous Material Spill Containment protocol. Contact your local Site Safety Officer and follow
instructions per the site policy and procedures.

The unit should be cleaned prior to first use.
Do not use spray on cleaners or disinfectants. These can leak through openings and coat electrical

components. Do not use cleaners or disinfectants that contain solvents capable of harming paint
coatings or stainless steel surfaces. Do not use chlorine-based bleaches or abrasives; these

will damage the chamber liner.

Warning: Never clean the oven with alcohol or flammable cleaners.

Avertissement: Ne jamais nettoyer l'appareil à l'alcool ou avec des nettoyants inflammables.

Cleaning

Perform the steps below to clean the oven:

1. Remove all removable interior components (shelves) and accessories.

2. Clean the oven with a mild soap and water solution, including all corners. Do not use an
abrasive cleaner that will damage stainless steel surfaces. Do not use deionized water to
rinse or clean with.

3. Rinse with distilled water and wipe dry with a soft cloth.

4. Take special care when cleaning around the Main Temperature Control and Over
Temperature Limit sensor probes at the back of the chamber to prevent damage.

Disinfecting

Cary out the following steps to disinfect the oven, if required by your laboratory or production
protocol:

1. Turn the unit off. Carry out your disinfection protocol.

2. If allowed by your protocol, remove all shelving. Disinfect all corners. Take special care not
to damage the temperature sensor probes when disinfecting.

3. Disinfect the unit using commercially available disinfectants that are non-corrosive, non­abrasive, and suitable for use on stainless steel surfaces. Contact your Site Safety Officer
for detailed information on the disinfectants compatible with your study or production
protocol.

29 | P a g e

Calibrating the Temperature Display

1. Place the temperature sensor of the reference device inside the oven as
close as possible to the geometric center of the chamber.

a. Probes may be introduced through the chamber door space,

and the door closed over probe wires.

Note: A thermocouple sensor probe sleeve may be taped to the shelving, as
long as the exposed copper end is 2 inches (5cm) away from the shelf. An
exposed sensor probe in direct contact with the shelving may experience heat
sinking, which can result in an inaccurate temperature reading.

2. Place both dampeners in the fully closed position. Failure to do
so risks an inaccurate calibration due to decreased temperature
stability and uniformity.

Dampener Closed

3. Set the temperature set point to that of your application using the Set

the Oven Temperature Set Point procedure on page 22.

Set Temperature

MAINTENANCE (CONTINUED)

CALIBRATING THE TEMPERATURE DISPLAY

Note: Performing a temperature display calibration requires a suitable temperature sensor
reference device. Please see the Temperature Reference Device entry on page 5 for the device
requirements.

Temperature calibrations are performed to ensure that the oven temperature display matches the
actual air temperature inside the oven chamber. Each SMO forced air oven is calibrated at the
factory to 150ºC. Calibrate as often as required by your production or laboratory protocol, or
regulatory compliance requirements.

Prior to performing a temperature calibration the oven should be run at the temperature of your
application for at least 1 hour in order to allow the chamber temperature to stabilize. Failure to wait
for stabilization will result in an inaccurate calibration. After the chamber has stabilized a wait of 15
minutes without a change of ±0.1°C or greater should suffice for the chamber to re-stabilize after
brief disruptions such as, short door openings.

30 | P a g e

Procedure continued on next page

Calibrating the Temperature Display (Continued)

4. Allow the oven to run for at least 1 hour to come to temperature
and stabilize.

5. The oven is stabilized when no fluctuations of 0.1°C or greater
have been detected on the temperature reference device for 30

minutes.

Reference Device

6. Once the chamber temperature has stabilized, compare the reference
device and the oven display temperature readings.

a. If the readings are the same, or the difference between the

two falls within the acceptable range of your laboratory or
production protocol, the display is accurately showing the
chamber temperature.

b. The temperature calibration procedure is now complete.

Reference Device

Set Temperature



7. If there is a difference between the two readings, and that difference
falls outside your protocol’s acceptable range, offset the temperature
display value to match the reference device reading. See the next step.

a. If the door was opened to check a reference device

temperature inside the chamber wait 15 minutes after the

reference device stops fluctuating before proceeding.

Reference Device

Set Temperature



8. Place the unit in temperature calibration mode.
a. Press and hold both the UP and DOWN arrow buttons

simultaneously.

b. The Temperature Display will show the letters “CO”, then

begin flashing the current temperature value.

Set Temperature



9. Use the Up or Down arrows to adjust the current temperature
value until it matches the reference device temperature reading.

a. If an arrow key is not pressed for five seconds, the

Temperature Display will cease flashing, and store the last
displayed value as the new current chamber temperature
value.

Set Temperature



Reference Device

MAINTENANCE (CONTINUED)

Procedure continued on next page

31 | P a g e

Calibrating the Temperature Display (Continued)

10. After entering the correction adjustment, wait 5 seconds.
a. The temperature display will cease flashing and store the

correction as an offset.

b. The oven will now begin heating or allow itself to cool in

order to reach your set point with the corrected display
value.

Set Temperature

Heating with Adjusted Value

11. Wait for 30 minutes with no fluctuations of ±0.1°C or
greater after the oven has achieved the set point with
the corrected display offset. Failure to wait until the unit is
fully stabilized will result in an inaccurate reading.

Reference Device

12. Once the temperature has stabilized, compare the reference device

and the oven display temperature readings.

a. If the readings are the same, or the difference between

the two falls within the acceptable range of your protocol,
the oven is calibrated for temperature.

b. The Temperature Calibration procedure is complete.

Reference Device

Set Temperature



13. If the two readings still fall outside your protocol’s acceptable range,

repeat 8 – 12.

a. If the temperature readings of the oven and the reference

device fall outside your protocol after three calibration
attempts, contact Technical Support or your distributor
for assistance.

Reference Device

Set Temperature



MAINTENANCE (CONTINUED)

32 | P a g e

End of procedure

MAINTENANCE (CONTINUED)

DOOR COMPONENTS

Periodically, inspect the door latch, trim, and catch for alignment. Check the two silicon rubber
gaskets located on the door and on the doorframe of the oven body for signs of drying, brittleness
or cracking. Failure to maintain the integrity of the door system shortens the lifespan of the oven
and may adversely impact chamber temperature uniformity and stability.

Replacement of the door liner and chamber liner gaskets is a service-level procedure.

ELECTRICAL COMPONENTS

Electrical components do not require maintenance. If the unit electrical systems fail to operate as
specified, please contact your distributor or Technical Support for assistance.

33 | P a g e

Model

Shipping

Net Weight

SMO14-2

360lbs. / 163kgs

280lbs. / 127kgs

SMO28-2

495lbs. / 225kgs

390lbs. / 177kgs

SMO28G-2

495lbs. / 225kgs

390lbs. / 177kgs

Model

Exterior W × D × H

Interior W × D × H

SMO14-2

37.5 x 34 x 48 inches

30.8 x 24.8 x 31 inches

SMO28-2

37.5 x 35 x 78.3 inches

30.8 x 25 x 62 inches

SMO28G-2

37.5 x 35 x 78.3 inches

30.8 x 25 x 62 inches

Model

Exterior W × D × H

Interior W × D × H

SMO14-2

95 x 86 x 121 cm

78 x 63 x 79 cm

SMO28-2

95.3 x 88.9 x 198.8 cm

78.1 x 63.5 x 157.4 cm

SMO28G-2

95.3 x 88.9 x 198.8 cm

78.1 x 63.5 x 157.4 cm

Model

Cubic Feet

Liters

SMO14-2

13.65

387

SMO28-2

27.5

781

SMO28G-2

27.5

781

UNIT SPECIFICATIONS

These ovens are 230 voltage units. Please refer to the oven data plate for individual electrical
specifications.

Technical data specified applies to units with standard equipment at an ambient temperature of
25°C and a voltage fluctuation of ±10%. The temperatures specified are determined in accordance
to factory standard following DIN 12880 respecting the recommended wall clearances of 10% of the
height, width, and depth of the inner chamber. All indications are average values, typical for units
produced in the series. We reserve the right to alter technical specifications at all times.

WEIGHT

DIMENSIONS

By Inches

By centimeters

CAPACITY

34 | P a g e

Model

Per Shelf

Total

SMO14-2

75lbs / 34kg

225lbs / 102kg

SMO28-2

75lbs / 34kg

450lbs / 204kg

SMO28G-2

30lbs* / 13.6kg

60lbs / 27.2kg

Model

Range

Uniformity

Stability

SMO14-2

Ambient. +15 to 260C

+ 3.0 @ 150C

± 0.2C

SMO28-2

Ambient +15 to 260C

+ 3.5 @ 150C

± 0.2C

SMO28G-2

Ambient +15 to 260C

+ 3.5 @ 150C

± 0.2C

Model

Heat Up Time to 150°

Recovery to 150°

SMO14-2

24 minutes

8 minutes (door open 30 seconds)

SMO28-2

24 minutes

10 minutes (door open 30 seconds)

SMO28G-2

24 minutes

10 minutes (door open 30 seconds)

Model

AC Voltage

Amperage

Frequency

SMO14-2

230

12

50/60 Hz

SMO28-2

230

20

50/60 Hz

SMO28G-2

230

20

50/60 Hz

UNIT SPECIFICATIONS (CONTINUED)

SHELF CAPACITY BY WEIGHT

*30lbs with the weight evenly distributed across the shelf.

TEMPERATURE

POWER

35 | P a g e

Description

Parts Number

Adjustable Feet

2700506

Shelf Clip

1250512

Shelf, Stainless Steel, SMO14-2 SMO28-2

995-00006

Shelf, Wire, SMO28G-2

6800537NCF

PARTS LIST

ORDERING

If you have the Part Number for an item, you may order it directly from Sheldon Manufacturing by
calling 1-800-322-4897 extension 3. If you are uncertain that you have the correct Part Number, or
if you need that specific item, please contact Sheldon Technical Support for help at 1-800-322-4897
extension 4 or [phone]. Please have the model number and serial number of the unit
ready, as Tech Support will need this information to match your unit with its correct part.

36 | P a g e