TestEquity 123C Operation manual

Copyright © 2011-2018 TestEquity LLC Rev. 2.2, February 1, 2018
Model 123C
Temperature Chamber
Serial Number 330218 and above
Operation and Service Manual
TestEquity LLC
6100 Condor Drive
Moorpark, CA 93021
Support: 877-512-3457 Toll Free
805-480-0638
Corporate: 800-732-3457
805-498-9933
http://www.testequity.com

Table of Contents
Chapter 1 – Safety Instructions________________________________________________ 1-1
Introduction ____________________________________________________________________1-1
Installation Safety Notices _________________________________________________________1-1
Operation Safety Notices __________________________________________________________1-2
Chapter 2 – Installation ______________________________________________________ 2-1
Uncrating_______________________________________________________________________2-1
Preparation For Use ______________________________________________________________2-1
Installation Location _____________________________________________________________2-2
Condensate Drain ________________________________________________________________2-2
Chapter 3 – Operation _______________________________________________________ 3-1
Introduction ____________________________________________________________________3-1
Summary of Chamber Operation ___________________________________________________3-1
Front Panel Switches and Lights____________________________________________________3-2
Power Switch _________________________________________________________________________ 3-2
Conditioning Switch – ON Mode __________________________________________________________ 3-2
Conditioning Switch – Event 1 Mode_______________________________________________________ 3-2
Light Switch __________________________________________________________________________ 3-2
HEAT Light __________________________________________________________________________ 3-2
COOL Light __________________________________________________________________________ 3-2
Loading the Chamber ____________________________________________________________3-3
Port Plugs ____________________________________________________________________________ 3-3
Performance Considerations ______________________________________________________________ 3-4
Avoiding Moisture _____________________________________________________________________ 3-4
Internal Test Fixtures ___________________________________________________________________ 3-4
Chapter 4 – Limit Controller__________________________________________________ 4-1
Introduction ____________________________________________________________________4-1
Limit Controller Keys and Displays ________________________________________________________ 4-2
How to Set the High and Low Temperature Safety Limits _______________________________________ 4-2
Resetting an Out of Limit Condition________________________________________________________ 4-2
Silencing the Audible Alarm______________________________________________________________ 4-2
Protecting an Energized Test Sample _______________________________________________________ 4-3
Chapter 5 – Purge ___________________________________________________________ 5-1
Introduction ____________________________________________________________________5-1
GN2 (Gaseous Nitrogen) Installation (Option TE-1239) ________________________________________ 5-1
Dry Air Installation (Option TE-0017) ______________________________________________________ 5-1
Purge Operation _______________________________________________________________________ 5-2
Adjusting the Purge Flow ________________________________________________________________ 5-2
Relief Vent ___________________________________________________________________________ 5-2
Chapter 6 – Frequently Asked Questions________________________________________ 6-1
Chapter 7 – Specifications ____________________________________________________ 7-1
Model 123C Chamber Specifications ________________________________________________7-1
Chapter 8 – Maintenance _____________________________________________________ 8-1
Preventive Maintenance Intervals __________________________________________________8-1
Daily or As Needed_____________________________________________________________________ 8-1
Every 3 Months________________________________________________________________________ 8-1
Every 6 Months________________________________________________________________________ 8-1
Every 12 Months_______________________________________________________________________ 8-1

Table of Contents
Maintenance Procedures __________________________________________________________8-2
How to Clean the Chamber Interior and Exterior ______________________________________________ 8-2
How to Listen for Abnormal Noise or Vibration ______________________________________________ 8-2
How to Inspect the Door Seal _____________________________________________________________ 8-2
How to Inspect the Refrigeration Machinery Compartment ______________________________________ 8-3
How to Verify the Performance ___________________________________________________________ 8-4
How to Inspect the Electrical Compartment __________________________________________________ 8-5
How to Clean the Condenser______________________________________________________________ 8-5
How to Verify the Temperature Calibration __________________________________________________ 8-6
Theory of Operation______________________________________________________________8-7
Troubleshooting _________________________________________________________________8-9
Refrigeration System Charging Instructions _________________________________________8-11
R-404A High-Stage Charge _____________________________________________________________ 8-11
R-508B Low-Stage Charge ______________________________________________________________ 8-11
Recommended Spare Parts _______________________________________________________8-12
Major Electrical Parts ___________________________________________________________8-13
Major Refrigeration Parts ________________________________________________________8-14
General Parts __________________________________________________________________8-14
EZ-Zone Limit Controller Setup Parameters ________________________________________8-15
Setup Menu __________________________________________________________________________ 8-15
Operations Menu______________________________________________________________________ 8-15
Chapter 9 - Warranty________________________________________________________ 9-1
Chapter 10 – Drawings______________________________________________________ 10-1

Chapter 1 – Safety
TestEquity 123C Temperature Chamber Page 1-1
Chapter 1 – Safety Instructions
Introduction
Follow all CAUTION notices to prevent damage to the chamber or your test sample. Failure to
follow all CAUTION notices may void your warranty. CAUTION may also indicate a
potentially hazardous situation which, if not avoided, may result in minor or moderate personal
injury.
WARNING indicates a potentially hazardous situation which, if not avoided, could result in
death or serious injury.
The safety alert symbol !precedes a general CAUTION or WARNING statement.
The electrical hazard symbol 2precedes an electric shock hazard CAUTION or WARNING
statement.
Installation Safety Notices
2WARNING: The power cord is equipped with a NEMA 5-20P grounded/polarized plug. To
prevent a shock hazard, DO NOT defeat the ground or polarization feature.
This device MUST be plugged DIRECTLY into a properly grounded and
polarized NEMA 5-20R receptacle. Due to high current demand on start-up,
use of an extension cord is NOT recommended.
!CAUTION: The minimum clearance you should allow for proper ventilation around the
chamber must be at least 6" from both the left and right side, and 12" from the
rear.
!CAUTION: This chamber is designed for operation in a conditioned laboratory
environment. Operation above 30°C (85°F) or below 16°C (60°F) ambient
room temperature is NOT recommended.

Chapter 1 – Safety
Page 1-2 TestEquity 123C Temperature Chamber
Operation Safety Notices
!CAUTION: The Temperature Controller’s “Alarm” functions are NOT used in the
chamber’s safety system and are NOT connected. TestEquity does NOT
recommend using the F4T/F4 alarm function as the main protection device.
The independent EZ-Zone Limit Controller functions as the main protection
device.
!CAUTION: The EZ-Zone Limit Controller has been properly configured by TestEquity to
match the chamber’s system requirements. Improper modifications to these
setup values can result in unreliable and unsafe operation. Do not attempt to
modify the setup values, unless you thoroughly understand what you are
doing. The correct values are documented in the “EZ-Zone Limit Controller
Setup Parameters” section of this manual.
!CAUTION: Always verify that the Limit Controller’s high and low limits are set to
temperatures that are appropriate for your test sample.
!CAUTION: If your test sample is energized, it may be capable of raising the workspace
temperature beyond safe limits. This could occur if your test sample exceeds
the live load rating of the chamber or if the chamber’s refrigeration system
fails. This chamber has a set of contacts that can be used to remove power to
your test sample if the Limit Controller’s temperature limits are exceeded.
!CAUTION: To prevent damage to your test sample and the chamber’s compressors, do not
exceed the live load rating of the chamber.
!WARNING: Do NOT put items in the chamber that could burn or explode at high
temperatures. This chamber uses open wire heating elements which generate
surface temperatures over 1000ºF. This is NOT an explosion-proof chamber.
!WARNING: Do NOT put items in the chamber which can emit corrosive vapors or
substances.
!WARNING: This chamber is NOT a curing oven. There are NO provisions for venting
fumes.
!WARNING: The chamber door must remain closed while the chamber is operating. If you
need to open the door while the chamber is operating, wear safety goggles to
prevent the high velocity airflow from blowing particles or objects into your
eyes.
!WARNING: This chamber operates at extreme temperatures. Avoid contact with air,
objects, and surfaces that are hot or cold to prevent severe burns or frostbite.
Protective gloves are recommended.

Chapter 2 – Installation
TestEquity 123C Temperature Chamber Page 2-1
Chapter 2 – Installation
Uncrating
Inspect the shipping container for any signs of visible damage. Notify the carrier and TestEquity
immediately if there are signs of shipping damage.
The pallet is designed with ramps so the chamber can be rolled off without the need for a forklift
or pallet jack.
1. Cut the two metal bands that hold the packaging to the pallet.
2. Remove the top cover.
3. Remove the plastic fasteners that hold the outer box together and remove the outer box.
4. Locate the retainer in the front of the pallet. Remove the two screws, then remove the
retainer. Keep in mind that there is also Velcro that holds the retainer in place. Place the
retainer in the front of the pallet on the floor.
5. Locate the two ramps under the chamber and remove them.
6. Attach the ramps to the front of the pallet using the Velcro straps. The retainer will be under
the ramps and act as a support.
7. Carefully roll the chamber off the pallet, onto the ramps. This should be done with at least
two people.
Preparation For Use
1. Inspect the chamber for signs of shipping damage.
2. Read this entire manual.
3. Select a suitable location to install the chamber.
4. Connect to the power source.
5. Perform following the procedures as described in the Preventive Maintenance section:
a. Inspect the electrical compartment.
b. Inspect the refrigeration machinery compartment.
e. Verify the chamber performance.

Chapter 2 – Installation
Page 2-2 TestEquity 123C Temperature Chamber
Installation Location
The chamber will produce a significant amount of heat during normal operation. Locate the
chamber in a room with adequate ventilation to prevent excessive heat build-up. The chamber
generates a heat load of up to 5,000 btuh during a continuous cool down from a high
temperature.
The chamber must be on a solid and level floor. Allow enough space around the chamber to
permit serviceability and the removal of the service access panels, which are located on each side
and the rear.
!CAUTION: The minimum clearance you should allow for proper ventilation around the
chamber must be at least 6" from both the left and right side, and 12" from the
rear.
!CAUTION: This chamber is designed for operation in a conditioned laboratory
environment. Operation above 30°C (85°F) or below 16°C (60°F) ambient
room temperature is NOT recommended.
Condensate Drain
The chamber has a condensate drain connection on the rear of the chamber. This provides a way
to remove condensate that may accumulate in the chamber during low-to-high temperature
cycling or when the refrigeration system runs to maintain moderate temperatures. Any time the
ambient air is subjected to temperatures below the dew point, moisture will condense out of the
air. The effect is ice or frost during low temperature operation. When the chamber is heated
above 0°C, the ice or frost will turn into water.
The fitting accommodates a ½-inch male pipe thread. The chamber drain water is not under
pressure, and is fed by gravity. Therefore, it must empty into an open floor drain. Alternatively,
the chamber drain can empty into a condensate pump. You can purchase a condensate pump
from suppliers such as Grainger (www.grainger.com).
Under most circumstances, you will not see any water coming out of the drain.

Chapter 3 – Operation
TestEquity 123C Temperature Chamber Page 3-1
Chapter 3 – Operation
Introduction
The Front Panel Switches control power to the chamber. The Front Panel Lights provide
indication of heat and cool functions.
The EZ-Zone Limit Controller is a protection device. It turns the chamber OFF if the workspace
temperature exceeds either a high temperature or low temperature limit set point.
The Temperature Controller controls the temperature of the chamber. The Temperature
Controller automatically turns the refrigeration system on or off as required based on the
deviation from temperature set point.
Refer to the separate F4T or F4 Temperature Controller manual for details on how to use
the Temperature Controller.
Summary of Chamber Operation
1. Turn the Power Switch ON.
2. Enter the appropriate high and low temperature safety limits on the Limit Controller.
3. Enter the desired set points (or program) on the Temperature Controller.
4. Load your test sample in the chamber.
5. Turn the CONDITIONING Switch ON. Alternatively, turn the CONDITIONING Switch to
the EVENT 1 position and turn the Power button on the F4T controller or EVENT 1 on the
F4 controller ON.

Chapter 3 – Operation
Page 3-2 TestEquity 123C Temperature Chamber
Front Panel Switches and Lights
Power Switch
The Power Switch controls power to the entire chamber. The Power Switch illuminates when it
is ON.
Conditioning Switch – ON Mode
The Conditioning Switch enables all chamber functions. When the Conditioning Switch is OFF
and the Power switch is ON, only the Temperature Controller and Limit Controller are
operational. When both the Power and Conditioning Switches are ON, the chamber’s
conditioning system will function to maintain the temperature set point. The Conditioning
Switch does not illuminate.
Conditioning Switch – Event 1 Mode
When the CONDITIONING Switch is in the EVENT 1 position, you can enable and disable all
chamber functions through the Power button on the F4T Temperature Controller or Event 1
(Digital Output 1) of the F4 Temperature Controller.
Light Switch
The Light Switch controls the workspace light. The Light Switch illuminates when it is ON.
HEAT Light
The HEAT Light will illuminate when the Temperature Controller turns on the heater to
maintain the workspace temperature. The HEAT Light will cycle on/off as the workspace
temperature approaches and reaches the temperature set point.
COOL Light
The COOL Light will illuminate when the Temperature Controller turns on the cooling valve to
maintain the workspace temperature. The COOL Light will cycle on/off as the workspace
temperature approaches and reaches the temperature set point.

Chapter 3 – Operation
TestEquity 123C Temperature Chamber Page 3-3
Loading the Chamber
!WARNING: Do NOT put items in the chamber that could burn or explode at high
temperatures. This chamber uses open wire heating elements which generate
surface temperatures over 1000ºF. This is NOT an explosion-proof chamber.
!WARNING: Do NOT put items in the chamber which can emit corrosive vapors or
substances.
!WARNING: This chamber is NOT a curing oven. There are NO provisions for venting
fumes.
!WARNING: The chamber door must remain closed while the chamber is operating. If you
need to open the door while the chamber is operating, wear safety goggles to
prevent the high velocity airflow from blowing particles or objects into your
eyes.
!WARNING: This chamber operates at extreme temperatures. Avoid contact with air,
objects, and surfaces that are hot or cold to prevent severe burns or frostbite.
Protective gloves are recommended.
!CAUTION: If your test sample is energized, it may be capable of raising the workspace
temperature beyond safe limits. This could occur if your test sample exceeds
the live load rating of the chamber or if the chamber’s refrigeration system
fails. This chamber has a set of contacts that can be used to remove power to
your test sample if the Limit Controller’s temperature limits are exceeded.
!CAUTION: To prevent damage to your test sample and the chamber’s compressors, do not
exceed the live load rating of the chamber.
Live Load Capacity for Model 123C
Temp +23°C 0°C –40°C –55°C –65°C
Watts 500 W 400 W 225 W 175 W 100 W
Port Plugs
Foam port plugs are provided with a gray silicone surface on one side. The port plug must be
inserted with the gray silicone surface facing the inside of the chamber. Port plugs should be
considered expendable and be replaced when they no longer provide a good seal.

Chapter 3 – Operation
Page 3-4 TestEquity 123C Temperature Chamber
Performance Considerations
The performance of all chambers is significantly affected by the characteristics of your test
sample. Factors include size, weight, material, shape, and power dissipation if energized.
The test sample should be placed in the chamber in a manner that allows for air circulation. The
air plenum is located on the back wall of the chamber, where air is sucked in from the bottom
and exits from the top. You should not place the test sample directly on the chamber floor. It
should be placed on the shelf. Multiple test samples should be distributed throughout the
chamber to ensure even airflow and minimize temperature gradients. If necessary, additional
shelves should be used to evenly distribute the load. Verify that the temperature gradients are
within acceptable limits, by measuring the chamber temperature at strategic points using a
multipoint thermocouple meter or data logger.
You may find that the temperature throughout the chamber is even, but always different from
what the temperature controller indicates. The correct way to adjust what the temperature
controller “displays” compared to what is measured at some point other than the controller’s
sensor is with the “Calibration Offset” parameter, NOT by recalibrating the controller.
Avoiding Moisture
Any time the ambient air is subjected to temperatures below the dew point, moisture will
condense out of the air. The effect is ice or frost during low temperature operation, or water
when maintaining over 0°C and cooling is required.
To avoid moisture condensation, make sure the port plugs are inserted at all times. Also, avoid
opening the chamber door while the chamber is operating at temperatures below room ambient.
When a low temperature test is completed, warm the chamber to at least room ambient before
opening the chamber door and before removing your test sample.
Internal Test Fixtures
Some applications require internal fixtures to support test samples and provide a convenient
method of connecting wires and sensors. Fixtures must be designed to minimize their impact on
chamber functionality and performance.
Fixtures should be designed for easy removal to permit maintenance and cleaning of the
chamber. The chamber liner should never be drilled or screwed into. This will compromise the
integrity of the liner and permit moisture migration due to condensation into the insulation,
which will eventually impact performance and lead to premature rusting of the outer cabinet.
Fixtures should be constructed of stainless steel. This also applies to all screws and fasteners. All
welds should be passivated. To prevent rust and corrosion, never use iron or mild steel even if it
is painted or plated. Aluminum may be used. However, since the specific heat of aluminum is
double that of steel, it represents a greater load and will have more impact on the chamber
performance.
Make sure that all connectors, wiring, pc boards, and auxiliary components can withstand the
temperature extremes that they will be subjected to. In some cases, these components may not be
able to last after repeated tests and should be considered expendable.

Chapter 4 – Limit Controller
TestEquity 123C Temperature Chamber Page 4-1
Chapter 4 – Limit Controller
Introduction
The EZ-Zone Limit Controller is a protection device. It turns the chamber OFF if the workspace
temperature exceeds either a high temperature or low temperature limit. You can set these limits
to correspond to the maximum and minimum temperature that your test sample can safely
withstand. This provides protection against someone setting the Temperature Controller to a
temperature that is unsafe for the test sample. It also provides protection in the unlikely event of
a chamber system component failure. The Limit Controller has its own temperature sensor
(thermocouple) and functions completely independent of the Temperature Controller.
This section provides a brief overview on how to operate the Limit Controller. For more detailed
instructions, see the “EZ-Zone User’s Manual”.
!CAUTION: The “EZ-Zone User’s Manual” is a general manual and is written by the
manufacturer, Watlow, for a wide variety of applications and configurations.
Not all features or functions are applicable. Only the capabilities of a model
PM6L1AJ-AAAABAA are applicable.
!CAUTION: The EZ-Zone Limit Controller has been properly configured by TestEquity to
match the chamber’s system requirements. Improper modifications to these
setup values can result in unreliable and unsafe operation. Do not attempt to
modify the setup values, unless you thoroughly understand what you are
doing. The correct values are documented in the “EZ-Zone Limit Controller
Setup Parameters” section of this manual.
!CAUTION: Always verify that the Limit Controller’s high and low limits are set to
temperatures that are appropriate for your test sample.
!CAUTION: If your test sample is energized, it may be capable of raising the workspace
temperature beyond safe limits. This could occur if your test sample exceeds
the live load rating of the chamber or if the chamber’s refrigeration system
fails. This chamber has a set of contacts that can be used to remove power to
your test sample if the Limit Controller’s temperature limits are exceeded.

Chapter 4 – Limit Controller
Page 4-2 TestEquity 123C Temperature Chamber
Limit Controller Keys and Displays
Figure 4-1 – Limit Controller Keys and Displays
How to Set the High and Low Temperature Safety Limits
1. Press the ‰key once to get the [`LL;s] prompt in the lower display. This is the Low Limit
Set Point prompt.
2. Press the ▲or ▼ key to enter the desired Low Limit Set Point in the upper display. Make
sure it is lower than your actual chamber temperature set point, and at least below room
temperature to prevent nuisance tripping.
3. Press the ‰key once again to get the [`lh;s] prompt in the lower display. This is the High
Limit Set Point prompt.
4. Press the ▲or ▼ key to enter the desired High Limit Set Point in the upper display. Make
sure it is higher than your actual chamber temperature set point to prevent nuisance tripping.
5. Press the RESET Key to return to the Home Page.
6. The upper display will show the actual chamber temperature while the lower display will
show [SAFE] as long as the limits are not exceeded.
Resetting an Out of Limit Condition
If the limit is exceeded, the Limit Controller will flash [Li;h1] (high limit) or [Li;L1] (low
limit) in the upper display and [Attn] in the lower display, alternating with the actual chamber
temperature in the upper display and [FAiL] in the lower display. It will also shut down all
chamber functions. The Limit Controller cannot be reset until the temperature returns to within
the limit set points. Then, you must press the RESET or EZ Key to resume normal operation.
Silencing the Audible Alarm
Turning off the Conditioning switch on the chamber front panel lets you temporarily turn off the
Audible Alarm, even though the High or Low Limit condition may still exist.

Chapter 4 – Limit Controller
TestEquity 123C Temperature Chamber Page 4-3
Protecting an Energized Test Sample
If your test sample is energized, it may be capable of raising the workspace temperature beyond
safe limits. This could occur if your test sample exceeds the live load rating of the chamber or if
the chamber’s refrigeration system fails.
This chamber has a set of safety contacts that can be used to remove power to your test sample if
the Limit Controller’s temperature limits are exceeded.
The safety contacts are rated as follows:
Resistive: 10 A, 250 VAC or 10 A, 28 VDC. Inductive: 7 A, 250 VAC
To access the safety contacts:
1. Unplug the chamber from the power source.
2. Remove the top cover.
3. Locate relay CR1 on the electrical sub panel as indicated below. Remove the retaining clip
and unplug the relay. Connections to the safety contacts are at relay CR1 socket, terminals 6
and 8. Plug in the relay and reposition the retaining clip when finished..
Figure 4-2 – Location of Safety Contact Connections on the Electrical Sub Panel

Chapter 5 – Purge
TestEquity 123C Temperature Chamber Page 5-1
Chapter 5 – Purge
Introduction
Optional GN2(gaseous nitrogen) Purge or optional Dry Air Purge can be used to reduce to
possibility of condensation in the chamber at low temperatures.
!CAUTION: Nitrogen cannot be detected by human senses. Nitrogen is non-toxic.
However, if adequate ventilation is not provided, nitrogen will displace air.
This can cause dizziness, unconsciousness or death without warning. The
chamber must be located in a well-ventilated area. Do not open the chamber
door with the GN2flowing.
GN2 (Gaseous Nitrogen) Installation (Option TE-1239)
Connect a supply of GN2 with a maximum pressure of 100 psig to the 1/4-inch FPT fitting which
is designated PURGE on the rear panel.
Dry Air Installation (Option TE-0017)
Connect the hose from the Dry Air system to the fitting which is designated PURGE on the rear
panel. Connect a supply of compressed air to the 3/8-inch FPT shutoff valve of Dry Air system.
This system requires a 5 cfm supply air flow rate at 100 psig (175 psig max).
Figure 5-1 – Dry Air Purge System Installation
Compressed Air Inlet to Dry Air System.
Shutoff v
alve on the Dry Air System is shown in the off
position.
Valve must be in the on position to operate.
Purge Inlet from Dry Air System
Connect to PURGE fitting on chamber.

Chapter 5 – Purge
Page 5-2 TestEquity 123C Temperature Chamber
Purge Operation
The Purge mode is enabled through the Purge button on the F4T controller or Event 2 (Digital
Output 2) in the F4 Controller.
Adjusting the Purge Flow
A flowmeter is located on the front panel to adjust the flow of purge gas into the chamber. The
flowmeter has a scale, calibrated in SCFM. The flow of purge gas should be adjusted to the
minimum amount required to obtain the desired drying in the chamber for your particular
conditions. A suggested starting setting is 2 SCFM.
Relief Vent
Excess pressure in the chamber workspace is vented through a pressure-relief check-valve,
which is located within the electrical compartment. There is no need to vent this externally.

Chapter 6 – Frequently Asked Questions
TestEquity 123C Temperature Chamber Page 6-1
Chapter 6 – Frequently Asked Questions
I need to send the chamber outside North America. Will it work with their power?
Outside North America, most countries have 50 Hz. Nominal voltages in are typically 220 V to
240 V. You CANNOT simply step the voltage down to 120 V because the compressors have a
50 Hz rating of 100 V nominal (95 V min. to 110 V max.).
Why does my chamber heat or cool slower than the published specifications?
Performance is significantly affected by the characteristics of your test sample. Factors include
size, weight, material, shape, and power dissipation if energized. The test sample should be
placed in the chamber in a manner that allows for air circulation. You should not place the test
sample directly on the chamber floor. It should be placed on the shelf. Multiple test samples
should be distributed throughout the chamber to ensure even airflow and minimize temperature
gradients. If necessary, additional shelves should be used to evenly distribute the load. You can
determine if the chamber is operating properly by following the procedure in “How to verify the
chamber performance”.
How can I modify the chamber to cool faster?
Unfortunately, there is little you can do to improve upon the designed-in performance.
TestEquity does NOT recommend using CO2or LN2in this chamber to achieve faster cooling
due to reliability and safety considerations, so it is NOT an available option. Modifying the
chamber to add CO2or LN2 will void the warranty.
Why is there water/ice/snow in the chamber?
Any time the ambient air is subjected to temperatures below the dew point, moisture will
condense out of the air. The effect is ice or frost during low temperature operation. When the
chamber is heated above 0°C, the ice or frost will turn into water. To avoid moisture
condensation, make sure the port plugs are inserted at all times. Also, avoid opening the chamber
door while the chamber is operating at temperatures below room ambient. When a low
temperature test is completed, warm the chamber to at least room ambient before opening the
chamber door and before removing your test sample.
My test specification requires convection heat only. Can I turn the circulator motor off?
NO! This will damage the heating and refrigeration systems and void the warranty. You need a
“gravity convection oven” for that kind of test.

Chapter 6 – Frequently Asked Questions
Page 6-2 TestEquity 123C Temperature Chamber
How accurate is the chamber?
That’s a loaded question! There is no “chamber accuracy” specification as such. The answer
requires an understanding of several performance parameters.
Control Tolerance – The F4 Controller uses a thermocouple control sensor, which is located in
the discharge airflow. Control tolerance is a measure of how much the temperature varies after
stabilization at the control sensor. It is a measure of the relative variations, NOT the absolute
accuracy of the readout. The control tolerance specification for this chamber is ±0.5°C, or a total
of 1°C. For example, the temperature set point may be –25.0°C. The actual temperature varies
between –25.4°C and –24.5°C. This corresponds to –0.4°C and +0.5°C or a total of 0.9°C of
RELATIVE variations. These specifications are for an empty chamber. The addition of a test
sample may affect the control variations. In some instances, the test sample will reduce these
variations.
Uniformity – Also known as Gradients. This is a measure of variations in temperature at
different locations throughout the chamber interior, at the same time, after stabilization. The
uniformity specification for this chamber is ±0.5°C or a total of 1°C, when measured at least 2"
away from the chamber interior walls. These specifications are for an empty chamber. The
addition of a test sample may affect the temperature uniformity. For example, an energized test
sample will produce a higher temperature near the sample.
Controller Accuracy – This is the ability of the temperature controller to accurately display a
temperature measurement when compared to a standard. The controller display accuracy is
±1.66°C. However, the total measurement accuracy in the chamber includes the thermocouple
sensor wire accuracy. Thermocouple wire accuracy is ±1°C or 0.75% of reading, whichever is
greater. Therefore, total system accuracy over the chamber’s operating range can be as much as
±2.66°C, although the typical accuracy is often better than ±1.0°C.
Can I tilt the chamber to move it?
You should be able to tilt the chamber 45 degrees to move it. After tilting it and moving it into
place, perform the steps as outlined in “How to inspect the refrigeration machinery
compartment” and “How to check the refrigerant charge” before placing the chamber back into
service to make sure that no damage has occurred.
I’m not going to use the chamber for a while. Is there anything I should do to prepare it for
storage?
Perform ALL the steps in the Preventive Maintenance Schedule before placing the chamber into
storage. This will ensure that the chamber will be ready to operate when it is taken out of storage.
If the chamber has a problem and is still under warranty, these problems should be resolved
before being placed into storage, since the warranty period starts from the date of shipment. The
chamber should be stored in a conditioned environment. Do not store it outside or where it will
be subjected to dirt or excessive moisture.
I haven’t used the chamber for a while. Is there anything I should do to prepare it for
operation?
Perform ALL the steps in the Preventive Maintenance Schedule before placing the chamber back
into service. This will ensure that nothing has been damaged and that a leak has not developed.