Tenney TJR, Junior, TU-JR Operation & Maintenance Manual

TENNEY ENVIRONMENTAL

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

Page 1

Tenney Junior

Environmental Test Chamber

OPERATION & MAINTENANCE MANUAL

Model No. TJR, Serial No. 3xxxx

Chamber Type: Temperature

Controller: Watlow 942

CHAMBER OPTIONS

G TempGard IV - Watlow 93 G GN2 Purge
G Boost Heat - Watlow 147 G Data Communications
G LN2 Boost Cooling G LinkTenn32 Software
G CO2 Boost Cooling G Chart Recorder
G Dry Air Purge G Alternate Controller - Watlow F4

TPS - Thermal Product Solutions

2121 Reach Road

Williamsport, PA 17701

570-326-1770 Fax: [phone]

Rev. 04/30/04

The Tenney Junior Family

Advanced Test Equipment Rentals

www.atecorp.com 800-404-ATEC (2832)

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TENNEY ENVIRONMENTAL

TABLE OF CONTENTS

SECTION Page

INFORMATION

1.0 COMPANY INFORMATION & ASSISTANCE ____________________________________ 4

2.0 SAFETY WARNINGS & SYMBOLS ___________________________________________ 5,6

3.0 PRODUCT SPECIFICATIONS & OVERVIEW ___________________________________ 7,8

4.0 DRAWINGS, INFORMATION, and VENDOR INSTRUCTION LISTINGS ______________ 9

5.0 INSTALLATION INSTRUCTIONS

5.1 Delivery and Uncrating of Unit ________________________________________________ 10

5.2 Location and Installation of Unit ______________________________________________ 10

5.3 Air Supply Connection - - - (for optional equipment) _______________________________ 11

5.4 GN2 Connection - - - (for optional equipment) ___________________________________ 11

5.5 LN2 Connection - - - (for optional equipment) ____________________________________ 12

5.6 CO2 Connection - - - (for optional equipment) ____________________________________ 12

5.7 Electrical Specifications ____________________________________________________ 13

5.8 Power Connection _________________________________________________________ 13,14

5.9 Application of Power _______________________________________________________ 14

5.10 Operating With an Active Heat Load ___________________________________________ 14

SYSTEMS and CONTROL

6.0 AIR CIRCULATION SYSTEM ________________________________________________ 15

7.0 TEMPERATURE CONTROL

7.1 Controller Features ________________________________________________________ 16,17

7.2 Watlow 942 Control Functions _______________________________________________ 18,19

7.3 Watlow F4 Control Functions (Alternate Controller) _______________________________ 19

8.0 HEATING DESCRIPTION ___________________________________________________ 20

9.0 CHAMBER OVERTEMPERATURE PROTECTION _______________________________ 20-22

10.0 CASCADE REFRIGERATION SYSTEM ________________________________________ 23,24

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

OPTIONAL EQUIPMENT and FEATURES

11.0 ALARM and SHUTDOWN CIRCUIT - TempGard IV (Optional)

11.1 System Description ________________________________________________________ 25

11.2 Special Hookup of TempGard IV for Model TJR ONLY _____________________________ 26

11.3 Circuit Operation __________________________________________________________ 27

11.4 TempGard IV Alarm Setpoint Entry ____________________________________________ 28

12.0 BOOST HEAT (Optional) __________________________________________________ 29

13.0 DRY AIR PURGE SYSTEM (Optional) ________________________________________ 30

14.0 GN2 PURGE AIR SYSTEM (Optional) ________________________________________ 31

15.0 LN2 BOOST COOLING SYSTEM (Optional) ___________________________________ 32

16.0 CO2 BOOST COOLING SYSTEM (Optional) ___________________________________ 33

17.0 LinkTenn32 SOFTWARE (Optional) __________________________________________ 34

18.0 CHART RECORDER (Optional) _____________________________________________ 35

CHAMBER OPERATION & MAINTENANCE

19.0 SEQUENCE of OPERATION ________________________________________________ 36,37

20.0 PREVENTATIVE MAINTENANCE ____________________________________________ 38,39

21.0 SERVICING CASCADE REFRIGERATION SYSTEMS ____________________________ 40-43

22.0 CHAMBER TROUBLESHOOTING GUIDE ______________________________________ 44,45

SUPPLEMENTAL INSTRUCTIONS

Revision History

♦ Original Document Dated 04/27/04

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

1.0 COMPANY INFORMATION & ASSISTANCE

Congratulations on purchasing a chamber from one of the fine divisions of TPS - Thermal Product Solutions.
You probably already know us as Lunaire Limited. We’ve changed our name and expanded our vision with
the intent to provide you with more diversified solutions to your thermal product process requirements.

We truly hope that every aspect of chamber design and quality will measure up to your strictest standards.
Your chamber has been designed to operate with the reliability you expect for the demands you impose on
your product and research testing.

Headquartered in Williamsport, Pennsylvania, which is located in the North-central part of the state, TPS
includes the following four divisions that manufacture environmental test chambers and industrial ovens.

Tenney Environmental - - - - - - Lunaire Environmental - - - - - - Gruenberg Oven - - - - - - Blue M

Parts and service inquiries for equipment within each division should be directed to Lunaire Limited by any of
the following methods.

Important! Please have the Model and Serial Numbers of your unit available when contacting us.

TPS
2121 Reach Road
Williamsport, PA 17701

Phone: 570 - 326 - 1770

Fax - Parts Dept. 570 - 320 - 2160

Fax - Service Dept. 570 - 326 - 3372

Fax - Main: 570 - 326 - 7304

E - Mail Address: [e-mail]

Web site: www.thermalproductsolutions.com

Parts Replacement

Your equipment has been designed and manufactured to provide years of reliable service. In the event a
component should fail, it is recommended that only OEM approved parts be used as replacements. Please
contact the Parts Department for component replacement, or repair.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

2.0 SAFETY WARNINGS & SYMBOLS

1. Read this entire Operation Manual, as well as the vendor manuals and cut-sheets provided before
operating this equipment! Failure to adhere to any Safety Warning, or failure to follow the proper
operating procedures listed throughout any of the information provided, could cause damage to your
equipment, personal injury, or death.

2. Do not use this equipment in any manner not specified in this manual. Improper use may impair the
safety features employed and will void your warranty.

3. For chambers that are not rated Explosion Resistant: The air conditioning section contains low mass,
open wire heating elements. Due to this low mass, the heater elements can readily attain temperatures
sufficiently high to ignite gas vapors. Do not install test articles that may release explosive or
flammable vapors in the chamber.

4. Only qualified service personnel should ever be permitted to perform any service-related procedure on
this equipment!

5. Do not place the unit near combustible materials or hazardous fumes or vapors.

6. Do not install unit in a corrosive environment. A corrosive environment may lead to poor performance
and deterioration of unit.

7. Make sure the chamber and any remote equipment provided are leveled when installed.

8. A main power disconnect may not be provided with your unit. If not provided, we recommend that a
fused disconnect switch on a separate branch circuit be installed as the power source in accordance
with all National and Local Electrical Codes. If your unit is equipped with a power cord and plug, you
must utilize a receptacle with the appropriate rating, which is on a branch circuit of its own.

9. Do not position the chamber in a manner that would make it difficult to operate your main power
disconnect switch.

10. Your power supply line voltage may be too low or too high to properly and safely operate your
equipment. Before making the power supply connection to your equipment, you must follow the
specific directions stated under “Power Connection” in the Installation Instructions section. Failing to
perform the directions stated may damage your equipment and void your warranty!

11. Control panels, gauge boxes, the conditioning compartment, etc., contain exposed electrical
connections. Keep panels in place properly when the unit is in operation. Disconnect and Lock-Out /
Tag-Out all electrical power from the unit at its source before servicing or cleaning.

12. Refrigerant under high pressure is used. Only qualified refrigeration mechanic personnel should ever
be permitted to perform any service-related procedure on the refrigeration system.

13. Do not adjust any mechanical components such as refrigeration valves or any electrical components
except as directed in this manual.

14. Human exposure to temperature extremes can cause injury. Take appropriate precautions before
opening chamber doors and upon handling test specimens.

15. Do not modify any component on this unit. Use only original equipment manufactured (OEM) parts as
replacement parts. Modifications to any component, or the use of a non-OEM replacement part could
cause damage to your equipment, personal injury, or death.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

INTERNATIONAL WARNING / SAFETY SYMBOL DEFINITIONS

Obey all “DANGER”, “WARNING”, and “CAUTION” labels shown in the manual and mounted on the
equipment. Do not remove any labels mounted on the equipment.

“WARNING OF HAZARDOUS AREA”

“WARNING OF DANGEROUS ELECTRIC VOLTAGE”

“WARNING OF HOT SURFACE”

“EARTH (GROUND) PROTECTIVE CONDUCTOR TERMINAL”

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

3.0 PRODUCT SPECIFICATIONS & OVERVIEW

Application:

This manual applies to the following reach-in temperature test chambers, which employ a capillary tube type
refrigeration system.

Model TJR: Tenney Junior - Benchtop Unit

Model TU-JR: Tenney Junior - Upright Unit

Specifications:

♦ Temperature Range: -75 to +200 degrees Celsius, ±0.3 degrees Celsius
♦ Workspace: 15-5/8" W x 11" D x 11-3/4" H (40 W x 28 D x 30 H Centimeters)

Note: This manual may also apply to special chambers with alternate model numbers (listed below).

For Model XXXX, S/N xxxxx, the following custom specifications apply:

♦ Temperature Range: - xx° to + xxx° C, +/- xx deg. after stabilization

Environmental Conditioning Functions:

♦ Heating of the chamber is achieved by recirculating chamber air through open-air nichrome wire heater

elements.

♦ Cooling of the chamber is achieved by recirculating chamber air through a refrigerated cooling coil in

the chamber conditioning section. The chamber is equipped with a cascade refrigeration system. Non­CFC refrigerants are used.

♦ Air circulation is generated by a propeller type fan, which is driven by an externally mounted motor.

Temperature Controller:

Either the standard Watlow 942 Controller or the optional Watlow F4 Controller is used for temperature
control. The type used is indicated on the manual cover page.

♦ Watlow 942 (Standard): The Watlow 942 Controller is a ¼ DIN profiling type controller. Profile

operations include 24-step program capability, time/temperature profile - rate, or time - based
programming, guaranteed soak deviation, and program looping. The W942 can also be used for simple
single, or fixed set point operation.

An RTD sensor is used for temperature measurement. Dual outputs are configured in the time
proportioned, On/Off, or switched dc modes. Two optional auxiliary outputs can be set up as alarms, or

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

time-based events. Optional retransmit output allows the retransmit of set point or process variable.
Data communications is optional using RS232/RS423, RS422, EIA-485, or IEEE interface.

♦ Watlow F4 (Optional): The Watlow F4 Controller is a ¼ DIN profiling type controller, which is

designed for demanding ramp and soak applications. Up to 256 steps can be programmed into as
many as 40 variable-length, nameable profiles. A four line high definition LCD interface display
enhances guided software to make profile programming and controller configuration faster and easier.
A 16-bit microprocessor provides this operational versatility, along with precise process control. The F4
can also function as a static set point controller. EIA-232 and EIA-485 serial communications with
Modbus RTU protocol is standard.

Chamber & Product Over/Under Temperature Protection:

Chamber overtemperature protection is provided with a thermal cutoff device. Product over/under
temperature protection may be provided with an optional alarm output from the main controller. The optional
TempGard IV feature with the Watlow 93 Controller may be used for redundant product over/under
temperature protection. These devices are configured in a comprehensive alarm and shutdown circuit.

Additional Options:

Your Tenney chamber may include many other options such as boost heating, boost cooling using LN2 or
CO2, a purge air system using compressed air or GN2, a chart recorder, and LinkTenn32 software.
LinkTenn32 is an enhanced software program that provides centralized remote monitoring, and the control of
multiple process controllers / chambers simultaneously.

As you can see, Tenney Environmental Test Chambers are diversified tools designed to encompass a wide
range of operating conditions and functions. If you come upon any questions as you continue on through the
manual, please contact our Service Department.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

4.0 DRAWINGS, INFORMATION, and VENDOR INSTRUCTION LISTINGS

The following drawings are provided:

Electrical Schematic - Model TJr. (Std. with Watlow 942 Controller) E - 2684 - 4

Electrical Schematic - Model T-U Jr. (Std. with Watlow 942 Controller) E - 2686 - 4

Electrical Schematic (Std. with Watlow F4 Controller) E - 2515 - 4

Electrical Schematic (Special Chambers with any controller) E - 2xxx - 4

Power Transformer Options - Electrical Schematic (with option only) E - 2340 - 3

Boost Heat Option - Electrical Schematic (with option only) E - 1873 - 3

Refrigeration Schematic R - 904 - 4

The following vendor manuals and information are provided:

Watlow 942, or F4 Controller Manual

Test Report

Optional Equipment – Vendor manuals will be supplied when the option is included.

Data Communications Manual (W942 - Data Com. is separate, WF4 - Data Com. is integrated in main mnl.)

LinkTenn32 Software

Watlow 93 Controller Manual (TempGard IV Feature)

Watlow 147 Limit Controller Manual

Chart Recorder Manual

Heatless Dryer Manual (with dry air purge option)

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

5.0 INSTALLATION INSTRUCTIONS

Read this section completely before attempting to install, or operate the equipment.

5.1 Delivery and Uncrating of Unit

Inspect equipment and shipping crate immediately upon receipt. If any damage is apparent, you should
discuss it with the trucking delivery person and contact the transportation company immediately. Make notes
of any damage on the Bill Of Lading. Retain all shipping materials for inspection. Any claims for damage
must start at the receiving point. Check packing slip carefully and make sure all materials have been
received as indicated on the packing ticket. Unless otherwise noted, YOUR ORDER HAS BEEN SHIPPED
COMPLETE.

Chambers and any remote machinery skids or control cabinets should be handled and
transported in an upright position. They must never be carried on their back, front, or any side.

Important! Inspect the circulation fan inside the chamber. The fan is driven by a motor that is mounted in
isolation bushings. Sometimes during shipping, the motor is pushed out of vertical alignment. If this has
occurred, the fan blade will strike the casing. Eliminate the interference by pushing the motor back into
alignment on its rubber mounts. However, be sure that the shipping abuse was not so great that the
extension shaft on the fan has been bent.

Important! Do to the vibration incurred during shipping and handling, it is possible that mechanical
connections could become loose. Check all connections to make sure they are secure.

5.2 Location and Installation of Unit

Your equipment has been fully operated, tested, and balanced in our plant prior to shipment, unless notified
otherwise. Follow the installation requirements below.

♦ Chamber Weight: Approximately 260 lbs.
♦ Environmental Specifications (For CE European Marked Chambers Only)

Pollution Degree 2, Installation Category III

♦ Do not place the unit near combustible materials or hazardous fumes or vapors.
♦ Ventilation: The chamber should be installed in an area where there is good air ventilation, especially if

an air-cooled condenser is used. Allow a minimum of 18 inches between any wall and chamber side, or
to any equipment mounted to the chamber side.

♦ Do not install unit in a corrosive environment. A corrosive environment may lead to poor performance

and deterioration of unit.

♦ Do not position the chamber in a manner that would make it difficult to operate your main power

disconnect switch. See “Power Connection” below.

♦ Make sure the chamber is leveled when set up.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

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5.3 Air Supply Connection (For Optional Equipment)

Your chamber will require a compressed air supply for the Dry Air Purge System option. The system is
mounted on the back side of the chamber. The supply should be clean and dry, and range from 80 PSIG
min. to 100 PSIG max. The connection type is ¼” FPT. Make sure the connection is secure. Reference the
corresponding “Option” section in this manual, or your chamber specifications for more details.

Back Side o
Chamber (TJR)

Flow Adjustments:

Adjust the flow
adjustment valve at the

supply connection to
maintain 100 PSIG max.
Adjust the flowmeter
metering valve to
approximately 300 cubic
feet per hour.

Compressed Air Supply
Connection Input 1/4” FPT

5.4 GN2 Connection (For Optional Equipment)

Twin Tower
Heatless Dryer

Vent Port
Checkvalve

Metering Valve

Flow Adjustment Valve

Dry Air Purge System

Your chamber will require a supply of gaseous nitrogen
for the GN2 Purge System option. The supply may range
up to 100 PSIG maximum. The connection is type 1/8”
NPT. Make sure the connection is secure. Reference the
corresponding “Option” section in this manual and your
chamber specifications for more details.

Warning! Gaseous nitrogen displaces
oxygen. Make sure the area surrounding the
chamber is well ventilated to dilute the gas
vented from the chamber vent port
checkvalve.

GN2 Supply
Connection

Flow Adjustment:

1/8” NPT

Adjust the metering valve to maintain approximately 300
cubic feet per hour.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

Vent Port
Checkvalve

Chamber

ccess Port

Metering
Valve

GN2 Purge System

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TENNEY ENVIRONMENTAL

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5.5 LN2 Connection (For Optional Equipment)

Your chamber will require a supply of liquid nitrogen for the LN2 Boost Cooling option. The supply may range
up to 40 PSIG maximum. The connection is type 1/8” NPT. Make sure the connection is secure. Reference
the corresponding “Option” section in this manual and your chamber specifications for more details.

Warning! Gaseous nitrogen resulting from
vaporized LN2 displaces oxygen. Make sure the
area surrounding the chamber is well ventilated to

Vent Port
Checkvalve

dilute the gas vented from the chamber vent port
checkvalve!

LN2 Flow Adjustment:

LN2 systems are provided with a manually set flow adjusting
valve, which permits the adjustment of nitrogen flow to avoid
incomplete evaporation at varying LN2 supply pressures. As

Chamber

ccess Port

the chamber cools to the extreme cold temperature limit,
complete evaporation of liquid nitrogen may not occur if the
supply pressure is allowed to drop. Incomplete evaporation
will cause droplets of liquid to fall to the chamber floor and
cause puddling.

Do not allow liquid nitrogen to contact the door

LN2 Supply Connection &
Flow Adjustment Valve

gasket. Exposure to LN2 will damage the gasket
and violate the seal.

LN2 Boost Cooling

A setting of 4 turns open of the valve generally provides good
performance at a supply pressure of 20 to 25 PSIG. This valve may be readjusted as necessary to
accommodate the supply pressure at the end use point.

Note: Your equipment configuration may be slightly different from what is shown.

5.6 CO2 Connection (For Optional Equipment)

Your chamber will require a supply of liquid carbon dioxide for the CO2 Boost Cooling option. The supply
may range up to 1000 PSIG. The connection is type 1/8” NPT. Make sure the connection is secure.
Reference the corresponding “Option” section in this
manual and your chamber specifications for more details.

Warning! Carbon Dioxide gas displaces
oxygen. Make sure the area surrounding the
chamber is well ventilated to dilute the gas

Vent Port
Checkvalve

vented from the chamber vent port checkvalve!

Note: There is no flow adjustment for the CO2 supply. A

Chamber

fixed orifice on the injection port inside the chamber
regulates the supply.

CO2 Supply
Connection

Note: Your equipment configuration may be slightly
different from what is shown.

ccess Port

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

CO2 Boost Cooling

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TENNEY ENVIRONMENTAL

5.7 Electrical Specifications

18 A, 100 / 120 V, 50 / 60 Hz, 1 PH

Your main power fused disconnect switch should be fused at 20 Amps.

5.8 Power Connection

Warning! Before making the power supply connection to your unit, you must perform the

following procedure:

1. Verify the power supply voltage rating established for your chamber (listed above). The voltage rating
is also found on the serial tag on the side of the oven. Note the rated value here:

2. Measure and record the intended voltage source. Note the measured value here:

3. Reference the “Line Voltage Min/Max Tables” below. Verify that the power supply voltage source you

measured and recorded is within the minimum and maximum allowable operating voltages for your
chamber rating. If it is not within this operating range, do not make the power connection! Otherwise,
erratic operation and damage may occur to your equipment, which may void your warranty. If you have
any questions, please call the Lunaire Service Department.

Important! One of the most common causes of equipment malfunction is low line voltage as the power
source to the unit. Ordinarily in this condition, the heat output would be reduced and the system's motors
would operate erratically, eventually overheat, and shut down. You must be certain that your equipment is
connected to a circuit with an adequate voltage and current source. An oversupply voltage would also cause
erratic operation and eventual shutdown, or damage to your equipment.

- 60 HERTZ SUPPLIES -

LINE VOLTAGE MIN. / MAX. TABLE

Nominal

Voltage

120

208

230

60 Hz

Supply

Minimum

Voltage

Maximum

Voltage

108 127

198 218

207 253

Operation outside these

limits can result in damage

Nominal

Voltage

50 Hz

Supply

- 50 HERTZ SUPPLIES -

LINE VOLTAGE MIN. / MAX. TABLE

200

220

Minimum

Voltage

180 220

198 242

Maximum

Voltage

Operation outside these

limits can result in damage

to the system's motors.

to the system's motors.

For CE European Marked Chambers Only: Chamber Fuse Type and Rating

1FU (Qty. 1) Gould Model GDG1/2 .5 A, 250 VAC Time-Lag

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

Making the Power Supply Connection to the Chamber:

A main power disconnect is not provided with your chamber. We recommend that a fused disconnect switch
on a separate branch circuit be installed as the power source to your chamber, in accordance with all
national and local electrical codes. Reference your Electrical, or Power Schematic for all electrical
requirements.

The power connection is made via a cord and plug for standard units. Connect the plug to a receptacle that
has the appropriate power supply on a branch circuit of its own. If the TempGard IV option is included,

refer to the “Alarm and Shutdown Circuit - TempGard IV” section for the connection procedure.

For special units that have the power supply hard-wired to the chamber, connect incoming lines to the main
input connections provided in the control section.

Warning! High Accessible Current – An Earth connection is essential before connecting the
power supply. Make sure equipment is properly grounded in accordance with all codes.

5.9 Application of Power

♦ Before energizing any equipment, make a visual inspection for loose components, electrical

connections, fittings, etc. Shut all operating switches to the “OFF” position before energizing.

♦ Have trained personnel start and check out the equipment before its first cycle.

Motor Rotation Check: Units with three phase motors must be checked to insure proper motor rotation. A
red arrow is located on the motor housing to show proper rotation. If it is opposite, shut down the oven and
disconnect the main power supply source. Perform Lock-Out / Tag-Out Procedures established by your
company. Reverse two of the line feeds to obtain proper operation. Failure to check motor rotation may result
in DAMAGE TO THE EQUIPMENT due to opposite airflow, or no airflow.

5.10 Operating With an Active Heat Load

Note: This feature is only available with the TempGard IV option.

When operating with an active heat load, such as introduced by a powered test unit, this heat must be
removed or the chamber temperature will rise. The internal logic of the controller will automatically turn on
the refrigeration system to maintain a set temperature. Although a cooling system failure is not likely to
occur, it is always a possibility when mechanical systems are used. In the event of a cooling system failure
that results in an out of limit over temperature condition, one or more of the system safeties will remove
power from the system. However, heating will continue if power remains applied to the active load. To guard
against this continued heating, the product should be powered through the spare contacts of the Master
Contactor (CON) from the TempGard IV circuitry. This is described in the Alarm And Shutdown Circuit
section.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

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6.0

IR CIRCULATION SYSTEM

Tenney Junior Test Chambers are provided with an efficient airflow system that maintains maximum
temperature uniformity.

Plenum

Heaters &
Refrigeration
Coil

Air Circulation

Circulation Fan & Guard

Temperature Sensor ­TUJR Location

Air Circulation

Chamber air is conditioned in the ceiling plenum where the circulation fan, heater elements, and refrigeration
coil are located. A propeller type fan driven by an externally mounted motor generates airflow. The plenum
cover prevents direct heat radiation to the workspace.

Process air is drawn up into the left side of the plenum. It flows through the heater elements and the
refrigeration coil and is discharged by the fan down into the workspace. The cycle repeats. A 100 ohm
Platinum RTD sensor mounted below the fan measures discharge air temperature.

Heating
Elements

Refrigeration
Cooling Coil

Fan Blade

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

Conditioning Section

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TENNEY ENVIRONMENTAL

7.0 TEMPERATURE CONTROL

7.1 Controller Features

Temperature conditions are controlled with the standard profiling type Watlow 942 Controller. The alternate
Watlow F4 Controller may be used for more demanding applications. Both controllers are described below.

Watlow 942 Controller:

The Watlow 942 is a profiling type ¼ DIN controller with ramping and auto-tuning control. The following main
features are employed.

♦ Single Channel
♦ Profiling: Multiple Profiles, 24 Steps Max.
♦ Automatic & Manual Control
♦ 1 Input: Universal Type (RTD is Std.)
♦ 2 Control Outputs: Time Proportioned, or On / Off Control
♦ 2 Auxiliary Outputs - Optional: 1 or 2 Events, or 1 or 2 Alarms, or 1Retransmit w/Alarm, or w/Event
♦ Guaranteed Soak - Standard
♦ Communications: Serial - Optional

Watlow F4S Controller:

The Watlow F4S is a profiling type ¼ DIN controller with ramping and auto-tuning control. The following main
features are employed.

♦ Single Channel
♦ Profiling: Forty Profiles, 256 Steps
♦ Automatic & Manual Control
♦ 1 Input: Universal Type (RTD is Std.)
♦ 4 Digital Inputs
♦ 2 Auxiliary Analog Inputs - Optional
♦ 2 Control Outputs: Time Proportioned, On/Off, or 4-20 ma
♦ 2 Alarm Outputs
♦ 8 Digital Event Outputs
♦ 2 Retransmit Outputs - Optional
♦ Communications: EIA-232 and EIA-485 with Modbus RTU protocol

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

DATA COMMUNICATIONS - WATLOW 942

As an option, your chamber may include data communications with the main controller's serial port. When
employed, a Data Communications manual will be included in the Supplemental Instructions Section. As a
reference, the available data types are listed and briefly described below.

RS232C / RS423A: Both interfaces are compatible and use 3 wires: a single transmit wire; a single receive
wire; and a common line. The maximum wire length is 50 feet. Only a single chamber may be connected to
your computer. Data signals are measured as plus and minus 12 Volts to common with RS232C, and plus
and minus 5 Volts to common with RS423A.

RS422A: This interface uses 5 wires: a transmit pair; a receive pair; and a common line. Up to ten
chambers may be connected to your computer on a multi-drop network up to 4,000 feet long. Data signals in
each pair are measured as a plus or minus 5 Volt differential.

EIA-485: This interface uses only 2 wires. Both wires are used for transmitting and receiving data, and
therefore, only one device may talk at a time. Up to 10 chambers may be connected to your computer on a
multi-drop network up to 4,000 feet long. Data signals are measured as a plus or minus 5 Volt differential. An
EIA-485 card must be installed for signal conversion.

IEEE-488: This is a parallel multi-drop interface with several control and data lines. Each device connected
must be set to a unique address. Data from other test devices may also be collected. An IEEE-488 to serial
converter card must be installed. Maximum cable length is approx. 33 ft.

DATA COMMUNICATIONS - WATLOW F4

Data communications utilizes EIA-232 and EIA-485 serial interface with Modbus RTU protocol. Modbus RTU
enables a computer or PLC to read and write directly to registers containing the controller's parameters.
These data interface types are briefly described below.

Controller Configuration:

The pre-programmed controller configuration for your chamber is documented in the Test Report, which is
located in the Supplemental Instructions Section. Refer to the controller’s user manual for more information.

Important! The configuration set-up is mainly provided for your reference. Not all of the parameters shown
apply to your chamber. Changes to some of the set-up parameters may drastically affect your chamber
performance and void your warranty. Contact the Lunaire Service Dept. before attempting any changes.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

7.2 Watlow 942 Control Functions:

The Main Power switch 1SS must be turned ON to enable the conditioning control circuitry. 1SS will also turn
on the chamber conditioner fan.

The following descriptions detail the functions of the various outputs. Event outputs (user entered) are
provided mainly for special applications. These features are normally described in the “Options” section of
the manual.

- HEAT CONTROL -

1C - 01 - - This time proportioned output will trigger triac 1TRC to conduct and provide power to the electric

heaters.

- COOLING CONTROL -

1C - 02 - - This On/Off output will trigger triac 2TRC to conduct and energize the refrigeration system. The

high stage compressor will immediately start. The low stage compressor will start after a slight
delay from the Low Pressure Cut-In Switch PS2.

- EVENT OUTPUTS - (Optional)

1C - 03 - - This is Event No. 1, which serves as a compressor shutoff when going from a very low to a vary

high setpoint. In this scenario, any cycling of the compressors is not desired, and a heat
overshoot is tolerated. 1C-03 contacts are normally closed. They will open when the event is
turned ON to disable the Cooling Control Output.

For Model XXXX, SN xxxxx Only:

Event No. X - - Output 1C-0x:

WATLOW 942 COMPRESSOR TURN-ON LOGIC

In determining when to turn the refrigeration system On or Off, the controller’s logic will compare the
following signals and setpoints.

1. Actual Chamber Temperature 3. Hysteresis

2. Setpoint Temperature 4. Deadband

Hysteresis (HYS) and deadband (db) are parameters entered at the factory. Hysteresis is the temperature
change necessary to change the output from full ON to full OFF, and is detailed in the Setup Menu section in
the Watlow 942 Manual. Deadband is the span in which Output 1C-02 will remain ON below the controller’s
low setpoint, and is detailed in the Operation Menu section of the Watlow Manual. HYS and db are entered
in degrees Celsius. Deadband is always entered as a (-) minus. The logic is:

♦ Measured temperature rises above setpoint: Refrigeration turn-on = hysteresis minus deadband.
♦ Measured temperature falls below setpoint: Turn-on is always above setpoint.
♦ Turn-off is always below setpoint: Turn-on is always above setpoint.

Example Settings For HYS and db: See Next Page

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

Example Settings For HYS And db

HYS db Turn-On (Above SP) Turn-Off (Below SP)

Standard 4 -3 1 3

5-3 2 3

5-1 4 1

No Good 3 0 3 0

Chambers are shipped with HYS = 4, and db = - 3, as shown on the top line in the above examples. It is
unlikely a change to these settings will be required. Fortunately, these settings are not subject to “cold start”
default, and will remain valid after a power interruption. They are held in EEROM, not battery-backed RAM.

7.3 Watlow F4 Control Functions (Alternate Controller): The Main Power switch 1SS must be turned

ON to enable the conditioning control circuitry. 1SS will also turn on the chamber conditioner fan.

- HEAT CONTROL -

Output 1A - - This time proportioned output will trigger triac 1TRC to conduct and provide power to the

electric heaters.

- COOLING CONTROL -

Dig. Out #8 - - This digital On/Off output will energize solid state relay SSRx and a control relay, which

triggers triac 2TRC to conduct and provide power to the entire refrigeration system. The
high stage compressor will immediately start. The low stage compressor will start after a
slight delay from the Low Pressure Cut-In Switch PS2.

Note: Digital Output No. 8 serves as a Compressor Control output, which can save wear
on a compressor and prevent it from locking up from short cycling. Compressor On %
Power sets the power level that will switch this output (compressor & control circuitry) on.
Compressor Off % Power sets the power level that will switch the compressor off.

The compressor(s) will not turn on until the output power exceeds the Compressor On %
Power for a time longer than the Compressor On Delay. The compressor will not turn off
until the output power exceeds the Compressor Off % Power for a time longer than the
Compressor Off Delay.

To Clear an Alarm or Error:

In an alarm condition, an alarm message will appear on the Main Page (if this option has been selected on
the Setup Page). To silence it, move the cursor to the alarm message and press the Right Key >. A pop-up
message will confirm the silencing of the alarm, and the indicator light will go off.

When the condition causing the error or alarm is corrected, return to the error or alarm message on the Main
Page, and press the Right Key again. A pop-up message confirms the alarm is unlatched.

Cascade Temperature Control (Optional):

Note: Tenney chambers are set up to run in the “No Cascade” mode because of the many variations in

customer products that require special tuning with this option.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

8.0 HEATING DESCRIPTION

Heating of the chamber is accomplished with the use of open air low mass nichrome wire heating elements.
These elements have low thermal lag and provide rapid response to the controller's demands. The elements
are mounted in the plenum conditioning section. This isolates them from the workspace and prevents direct
radiation to the product. The heater bank is rated 500 Watts, consisting of two 250 Watt elements.

Heater Control:

The heaters are controlled by a time proportioned output from the main controller. This output triggers a triac
to conduct and provide power to the elements.

Note: The Boost Heat option may be provided to increase the rate of heating. Reference the “Boost Heat”
option section for details.

9.0 CHAMBER OVERTEMPERATURE PROTECTION

9.1 Overview

A thermal cutoff (labeled as Heat Limiter HL) is provided to protect the chamber against overtemperature
conditions. This is an axial leaded one-shot protection device, which is connected in-line with the mains
power supply Neutral Line, directly to the heater rack. The thermal cutoff will permanently open and remove
power from the heater elements when the surrounding air temperature reaches 240°C. Once the thermal

cutoff opens, it must be replaced.

Note: The thermal cutoff is not used when the Boost Heat option is employed. This option uses a Watlow

147 Limit Controller for overtemperature protection. Reference the “Boost Heat” option section for details.

Thermal Cutoff

Thermal Cutoff is installed
in the Neutral Line, and is
wrapped in glass cloth
electrical tape.

Heater Element Rack

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

9.2 Thermal Cutoff Replacement Procedure

WARNING! Before replacing the thermal cutoff, you must disconnect your power supply
cord and plug from the power supply receptacle. If your chamber is hard wired, you must
open the closest main power disconnect switch. Lockout / Tagout all electrical power to the

chamber before proceeding. Read the description below before attempting to replace this device.

1. Push in the RTD sensor probe with your finger

towards the wall of the chamber.

Important! DO NOT push the RTD probe all of
the way into the probe fitting. Leave between ½”
to ¾ ” sticking out.

RTD Sensor

TJR RTD Location

2. Remove the conditioner plenum cover

by removing the four mounting screws.
Be careful not to hit the fan blade or the
RTD probe when dropping the cover
down.

Note: In this photo, the RTD probe is
not pushed in.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

RTD Sensor

TUJR RTD Location

Screws

Plenum Cover Removal

Page 21

TENNEY ENVIRONMENTAL

3. Remove the two heater rack mounting screws and drop the rack to the bottom of the chamber.

Note: The back mounting screw is in a confined area.

Screws

Heater Rack Removal #1

4. The thermal cutoff is installed in-line with the Neutral

Line. It is wrapped with glass cloth electrical tape, Type
3M Scotch 27 (Lunaire P/N 914050). One side is
connected to the Neutral Line with a butt crimp
connector. The other side is connected to the heater
rack with a ring terminal, and is secured with an 8/32 nut.

Unwrap the tape and remove the thermal cutoff by
cutting it free of the Neutral Line at the butt connector,
and by removing the nut on the heater rack.

Thermal Cutoff

Replace the unit with a new thermal cutoff, along with
the proper butt splice and ring connector. Make sure you
wrap the new section properly with glass cloth electrical
tape.

As you install the new thermal cutoff and put the
plenum back together, take great care in your replacement procedure! Make sure all
connections are secure!

Heater Rack Removal #2

Thermal Cutoff Removal

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

A

r

10.0 CASCADE REFRIGERATION SYSTEM

Basic System Description:

This is a multiple refrigeration system consisting of a low stage and a high stage system. These systems are
integrated to efficiently provide very low temperature levels. This is achieved by utilizing a cascade
condenser in the low stage, where low stage refrigerant is cooled and condensed by the high stage
refrigerant. The cooled low stage refrigerant now has greater cooling capacity in the chamber evaporator
coil. An air-cooled condenser is used in the high stage.

ir - Cooled Condense

Compressors

TJR Machinery Compartment

TU-JR Machinery Compartment

Capillary Tube Control Description:

This system employs capillary tube type refrigerant control. A long length of seamless copper tubing with a
small internal diameter is used to feed the evaporator coil. The tube acts as an automatic throttle in
controlling refrigerant pressure and flow to the evaporator. With the compressor running, a high pressure is
maintained on the inlet to the capillary tube, and a low pressure is maintained in the evaporator. The
pressures will balance when the compressor is turned off. This places a low starting load on the compressor
motor when turned back on. A fine filter or filter-drier is provided at each capillary tube inlet to remove
moisture and dirt from the refrigerant.

Low Stage Description

The low stage system includes the compressor, the cascade condenser, an expansion tank, and the
evaporator coil located in the chamber conditioning section.

Refrigerant flow in the low stage is from the compressor as a hot compressed gas and then through a
desuperheater where most of the heat of compression is removed. The desuperheater is part of the high
stage air cooled condenser. As a cooled gas, it then flows to the cascade condenser where it condenses to

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

liquid form by heat exchange with circulating high stage refrigerant. The liquid refrigerant flows through a
drier assembly, and is metered through a capillary tube to the evaporator cooling coil in the chamber
conditioning section. Warm chamber air circulates through the cooling coil, and heat exchange occurs as the
liquid refrigerant boils, vaporizes, and absorbs heat. The vaporized refrigerant returns to the compressor
through the suction line. The cycle is repeated.

High Stage Description

The high stage system includes the compressor, an air cooled condenser, and a suction line accumulator to
guard against liquid refrigerant return to the compressor.

Refrigerant Flow:

Refrigerant flow in the high stage is from the compressor as a hot compressed gas, to the air cooled
condenser where the gas cools and condenses to liquid form. It then flows to the cascade condenser, being
metered by a capillary tube. In the cascade condenser, high stage refrigerant absorbs heat from the
circulating low stage refrigerant. As it absorbs heat, the high stage refrigerant boils and vaporizes. It then
returns to the compressor through the suction line accumulator SLA. The cycle is repeated.

Safety Devices

Low Pressure Cut-In Switch PS2:

The low stage compressor will start after a slight delay from the Low Pressure Cut-In Switch PS2, which
monitors the suction pressure in the high stage compressor. This switch will close when the suction pressure
reaches 20 PSIG. This delay prevents both compressors from hitting the power line at the same instant.

High Pressure Cut-In Switch PS1:

An Artificial Loading solenoid valve SV will be energized by the High Pressure Cut-in Switch PS1, when low
stage compressor head pressures reaches 280 PSI. This action dumps refrigerant into the expansion tank
for storage until the pressure drops to 240 PSI.

Compressor Motor Overloads:

A motor overload protective device is installed in the windings of each compressor, which will open if the
motor windings exceed a preset temperature. Probable causes are insufficient flow across the motor due to a
refrigerant loss, or a failure of the liquid injection valve provided for suction gas cooling. The motor overload
will automatically reset and restart the compressor after the motor has cooled.

NOTE: Please reference the section entitled “Servicing Cascade Refrigeration Systems” for a more detailed
description.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

Page 24

TENNEY ENVIRONMENTAL

A

)

11.0

LARM and SHUTDOWN CIRCUIT - TempGard IV (Optional

11.1 System Description

A comprehensive alarm and shutdown circuit may be provided for protection against product over/under
temperature. This optional feature utilizes a Watlow 93 Controller configured as a TempGard IV temperature
protector. The Watlow 93 is a microprocessor based controller that incorporates programmable high and low
temperature limits. A 100 ohm Platinum RTD is used for temperature measurement. It is placed near the
plenum in the downstream airflow, which is the most responsive area of the chamber. An Electrical
Schematic of the TempGard IV feature is included with this manual.

In the Model TUJR, the TempGard IV feature is integrated directly into the chamber power scheme. The
chamber comes equipped with a single power supply cord that plugs into a power supply receptacle.

In the Model TJR, the TempGard IV feature is enclosed in a separate control box and is mounted on top of
the unit. For shipping purposes, the TempGard control box is removed from the top of the unit and placed
inside the chamber workspace. The RTD wire that runs from the chamber thru the BX conduit and into the
TempGard control box is disconnected. The chamber power supply cord is unplugged from the TempGard
receptacle. Reference the following section for the complete wire and cable hookup procedure.

TempGard IV
Control Box

TempGard IV Panel

TJR - TempGard IV

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

TUJR - TempGard IV

TempGard IV Panel

Page 25

11.2 Special Hookup of TempGard IV for Model TJR ONLY

A

r

Controller

RTD Wires ­Connect to back
terminals of Watlow
93 Controller - See
Electrical
Schematic

TENNEY ENVIRONMENTAL

Watlow 93

TGIV RTD WIRE HOOKUP

TGIV Power
Supply Cord ­Connects to
Customer’s
Power Supply
Receptacle

RTD Connection on Watlow 93 TempGard IV Controller

larm Buzze

TJR - TempGard IV Connection - Rear View

Chamber Power Supply
Cord (from bottom rear
of chamber). Plugs into
TGIV Receptacle

BX Cable with RTD Sensor Wire

TempGard IV / Chamber Power Supply Configuration: Connect the TGIV power supply cord to your power
supply receptacle. Connect the chamber power supply cord to the receptacle on the back of the TGIV
enclosure.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

11.3 Circuit Operation

When chamber temperature is within the selected setpoints, the white NORMAL light 2LT is illuminated and
Master Contactor CON is energized. The contacts of CON provide power to the conditioning control circuitry.

Note: A spare set of CON contacts is provided for the customer’s closure. It is recommended that these
contacts be used to energize an active heat load if utilized.

When a preset temperature limit is reached within the Watlow 93, the alarm contacts TG will open and
deenergize CON, which causes the following to occur.

♦ Power is removed from the main temperature controller and conditioning circuitry.
♦ Alarm buzzer sounds.
♦ Alarm and Chamber Overtemp lights on the TempGard IV panel will illuminate. The lower display of the

Watlow 93 will blink with the corresponding alarm message, e.g., AHI and HI, or ALO & LO.

WARNING! When Master Contactor CON is deenergized due to an alarm condition, power is
only removed from the chamber circuitry. The instrumentation and alarm circuitry in the TempGard
IV control box will still be energized!

A Silence switch 4SS is provided to disable the alarm buzzer while corrective action is taken. When 4SS is
activated, the white Silence light 5LT will illuminate. When conditions are corrected, you must reset the
chamber power system.

RESET:

To reset the alarm circuitry and the main controller control circuitry, press the Chamber Power
switch on the TempGard IV panel. (The Power switch also serves as a Reset switch.)

Important: If the alarm buzzer was disabled and the system was successfully reset with the Power switch
2SS, the alarm buzzer will now sound to alert the operator to place the Silence switch 4SS in it’s off position.

A 1.5 second timer TC is included in the reset circuit to provide for automatic start when power is applied to
the system. This avoids the need for a manual reset each time that power is removed and reapplied.

The configuration for the TempGard IV option is detailed in the section entitled “TempGard IV Alarm Setpoint
Entry”, which follows. Reference the Watlow 93 user manual for complete details of the controller.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

11.4 TempGard IV Alarm Setpoint Entry

The purpose of this section is to explain how to set your low & high temperature alarm setpoints with the
optional TempGard IV. This feature is part of the optional Alarm And Shutdown Circuit described earlier.

Normal Conditions: When conditions are within the alarm setpoints, the upper display of the Watlow 93
will indicate the process temperature (normally in degrees Celsius), and the lower display will be blank.
Temperature measurements are made with a 100 ohm platinum RTD sensor.

Alarm Setpoint Entry Procedure: Disregard parameters not listed. (You will be in the Operation Menu.)

1. Press the Advance Key (key with two curved arrows) to scroll to the Alarm Low (ALO) parameter
(lower display). Use the Up / Down arrow keys to set the desired low alarm setpoint (upper display).

2. Press the Advance Key to scroll to the Alarm High (AHI) parameter (lower display). Use the Up / Down
arrow keys to set the desired high alarm setpoint (upper display).

3. After setting the low and high limit values, continue scrolling with the Advance Key until the Alarm Low
setpoint that you just entered appears in the lower

display. It will go blank after a few seconds.

Note: On the old style Watlow 965 Controller, you must press the “M” key to scroll in any menu.

Alarm Conditions: When an out of limit condition occurs, the lower display will flash “HI” or “LO”.

Important: When the alarm condition has cleared, the TGIV alarm will automatically reset. You must

then reset the chamber control circuitry by pressing the chamber Reset button. For Models TJR / TUJR only,
cycle the Chamber Power switch. These switches are on the TGIV panel.

Setup Menu: The Setup Menu is provided for reference only. It has already been configured. Do not
change any values unless circumstances demand it, such as when you need to change controllers.

To access the Setup Menu, press the Up Arrow and the Down Arrow keys simultaneously. Setup parameters
are shown in the lower display. Parameter values appear in the upper display. Press the Advance key to
scroll through the menu. Values for the Low Range Limit (rL) and the High Range Limit (rH) are the low and
high temperature ratings of your chamber, minus and plus 4 degrees, respectively.

SETUP MENU for WATLOW 93 - TEMPGARD IV

Parameter Value Parameter Value

LOC 1 Ot2 PrA

In rtd HSA 1

dEC (default) LAt Nla

C - F C SIL (default)

rL

Low Limit minus 4 deg.

rtd Din

rH

Ot1 ht P L 100

HSC (default) dSP Pro

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

High Limit plus 4 deg.

rP OFF

Page 28

TENNEY ENVIRONMENTAL

12.0 BOOST HEAT (Optional)

As an option, your chamber may be equipped with the boost heat feature, which includes extra heaters to
provide rapid increases in temperature. This feature is available in either a 500 W, or 1000 W version. The
boost heat will automatically turn on if a preset time delay relay times out, indicating that the desired
temperature has not been achieved.

As the heat output of the main controller energizes the main heater bank, it will at the same time energize
time delay relay TC, which is set for three minutes. When this relay times out it will energize mercury relay
MR, which provides power to the boost heaters.

With this option the Heat Limiter fuse is not used. In its place, a Watlow 147 Limit Controller 1TS is used
to monitor and protect the chamber against an overtemperature condition. This controller is an open board
type with an adjustable dial and a calibrated scale for selecting the high limit temperature setpoint. It is
installed inside the main control panel. A red LED on the Watlow 147 will illuminate in an alarm condition. A
Type T thermocouple is used for temperature measurement. Note: The high limit is preset at the factory and
should never be changed.

When the temperature is below the preset limit, 1TS contacts will be closed to energize contactor BHCON.
Separate contacts of BHCON are wired in series with both the existing heater elements and the boost heater
elements. When the Watlow 147 detects an overtemperature condition, 1TS will open to deenergize BHCON
and all heaters.

Reference the Boost Heat Electrical Schematic for more details.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

13.0 DRY AIR PURGE SYSTEM (Optional)

Note: Refer to the Installation Instructions Section for supply and connection type specifications.

A Dry Air Purge System may be provided to purge the chamber of moisture or undesirable process vapors. A
heatless desiccant dryer is operated with a compressed air supply to produce a source of dry air.

General Description:

The dryer is a twin tower heatless desiccant type that is self­regenerating. Each desiccant tower (chamber) contains a
compression packed molecular sieve. As the compressed air
passes through the sieve, moisture is picked up by the desiccant.
The dried air is released through an outlet port and injected into
the test chamber's conditioning airflow through solenoid valve
ASOL. A small portion of the dried air is passed through a sized
orifice to the other tower to purge the desiccant of moisture
collected during the previous cycle. There are four distinct phases
of the heatless dryer where the compressed air is alternately
cycled and dried in each of the two desiccant towers. Integral
timers and solenoid valves within the dryer control this operation.

Operation:

The system is activated by an Event Output from the main
controller (or by a manual switch). To use the system, the Event
must be turned ON. Reference the Event Label on the side of the
chamber or your Test Report for the Event Number assigned to

Heatless Desiccant Dryer

this feature. When the system is activated, both the dryer and the
Dry Air solenoid valve ASOL will energize.

Note: Your equipment configuration may be slightly different from what is shown.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

14.0 GN2 PURGE AIR SYSTEM (Optional)

Note: Refer to the Installation Instructions Section for supply and connection type specifications.

Warning! Gaseous nitrogen displaces oxygen. Make sure the area surrounding the chamber is
well ventilated to dilute the gas vented from the chamber vent port checkvalve!

General Description:

As an option, your chamber may be equipped with a GN2 Purge System to provide an inert atmosphere
inside the chamber. An inert atmosphere minimizes the buildup of moisture and prevents condensation on
the product under test. Eliminating oxygen in the chamber air helps prevent corrosion of the product.
Gaseous nitrogen is injected into the chamber through a header pipe in the conditioning plenum. It readily
mixes in with the circulating process air.

Operation:

The system is activated by an event output from the main controller (or by a manual switch). To use the
system, the Event must be turned ON. Reference the Event Label on the side of the chamber or your Test
Report for the Event Number assigned to this feature.

When activated, the event output will energize and open the GNSOL solenoid valve to permit the injection of
GN2. A metering valve and flowmeter is supplied as part of the system to establish the design purge flow.
The valve should be adjusted until the indicated flow is about 300 cubic feet per hour.

Note: Your equipment configuration may be slightly different from
what is shown.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

GN2 Purge System

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TENNEY ENVIRONMENTAL

15.0 LN2 BOOST COOLING SYSTEM (Optional)

Note: Refer to the Installation Instructions Section for supply and connection type specifications.

Warning! Gaseous nitrogen resulting from vaporized LN2 displaces oxygen. Make sure the area
surrounding the chamber is well ventilated to dilute the gas vented from the chamber vent port
checkvalve!

General Description:

The LN2 Boost Cooling System option may be provided to increase the rate or limit of cooling beyond the
means of the refrigeration system. Boost cooling is achieved by injecting liquid nitrogen into the chamber
through a port located on the bottom left side. LN2 has a boiling point of -196 degrees Celsius (-320 deg. F).
As the liquid sprays out of the port, it vaporizes and absorbs chamber heat while it mixes with process air. A
small metal deflection flange is mounted about an inch away from the LN2 port to deflect any liquid nitrogen
spray from hitting the product before it vaporizes.

LN2 systems are provided with a manually set flow adjustment valve, which permits the adjustment of
nitrogen flow to avoid incomplete evaporation at varying LN2 supply pressures. As the chamber cools to the
extreme cold temperature limit, complete evaporation of liquid nitrogen may not occur if the supply pressure
is allowed to drop.

Important! Incomplete evaporation will cause droplets of liquid to fall to the floor and may
promote puddling. If enough liquid accumulates, it may seep towards the chamber door gasket.
Do not allow LN2 to contact the door gasket. Exposure to LN2 will damage the gasket and violate
the seal.

Operation:

The system is activated by an event output from the main controller
(or by a manual switch). To use the system, the Event must be
turned ON. Reference the Event Label on the side of the chamber or
your Test Report for the Event Number assigned to this feature.

Once the system is enabled with the event output, the controller's
time proportioned Full Cooling output will energize a solid state On­delay timer. If the Full Cooling output remains on longer than ten
seconds, the timer will time out and energize the LN2 Injection
solenoid valve SOL. This valve will open to permit the flow of LN2
into the chamber to boost the cooling rate. As soon as the Full
Cooling output turns off, the timer output will open to deenergize SOL
and shut off the flow of LN2.

Note: Your equipment configuration may be slightly different from
what is shown.

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

LN2 Boost Cooling

Page 32

TENNEY ENVIRONMENTAL

16.0 CO2 BOOST COOLING SYSTEM (Optional)

Note: Refer to the Installation Instructions Section for supply and connection type specifications.

Warning! Carbon Dioxide gas displaces oxygen. Make sure the area surrounding the chamber is
well ventilated to dilute the gas vented from the chamber vent port checkvalve!

General Description:

The CO2 Boost Cooling System option may be provided to increase the rate of cooling beyond the means of
the refrigeration system. Boost cooling is achieved by injecting liquid carbon dioxide into the chamber
through an orifice within an injection port. There is no flow adjustment valve for the supply. CO2 has a boiling
point of -78.5 degrees Celsius (-109.3 deg. F). As the liquid sprays out of the orifice, it immediately vaporizes
and absorbs chamber heat while it mixes with process air.

Operation:

The system is activated by an event output from the main controller (or by a manual switch). To use the
system, the Event must be turned ON. Reference the Event Label on the side of the chamber or your Test
Report for the Event Number assigned to this feature.

Once the system is enabled with the event output, the controller's time proportioned Full Cooling output will
energize a solid state On-delay timer. If the Full Cooling output remains on longer than ten seconds, the
timer will time out and energize the CO2 Injection solenoid valve SOL. This valve will open to permit the flow
of CO2 into the chamber to boost the cooling rate. As soon as the Full Cooling output turns off, the timer
output will open to deenergize SOL and shut off the flow of CO2.

Note: Your equipment configuration may be slightly different from
what is shown.

CO2 Boost Cooling

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

17.0 LinkTenn32 SOFTWARE (Optional)

LinkTenn32 is a Microsoft Visual Basic Software application designed for the Microsoft Windows family of
PC Operating Systems. LinkTenn32 utilizes a Multi-Document Interface (MDI) familiar to Windows software
applications so more than one Environmental Chamber Window can be used at a time. LinkTenn32 provides
centralized remote monitoring and control of multiple process controllers simultaneously. LinkTenn32
supports the following controllers: Watlow 942 & F4, Lunaire VersaTenn III, IV, and V Controllers . The
major features provided include:

♦ Interactive remote control and monitoring.
♦ Alarm reporting and notification via Email or Fax.
♦ User-friendly profile program editor.
♦ Logging, printing and graphing of process data.
♦ Exporting of logging history data via an ASCII comma separated values (CSV) file for easy import into

Microsoft Excel or any analysis package that accepts comma separated values (CSV) file format.

The minimum hardware requirements for LinkTenn32 are as follows:

♦ One of these Microsoft Windows PC Operating Systems: Windows 95, 98, 98 Special Edition, NT 4.0

Service Pack 6a, 2000 Service Pack 2

♦ A Pentium Processor 233 MHz or better
♦ 128 MB Ram plus 32 MB for each simultaneous chamber session
♦ 40 MB hard disk space
♦ One serial port
♦ One National Instruments GPIB IEEE Interface (Optional)
♦ One 10/100 Ethernet card using TCP/IP (Optional)
♦ Printer (Optional)
♦ Fax Modem (Optional)

Example Screens:

-

LinkTenn32 Sample Graph Screen - 2 Channel

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

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TENNEY ENVIRONMENTAL

18.0 CHART RECORDER (Optional)

As an option, your chamber may be provided with either a circular or strip type chart recorder to record
temperature versus time. This recorder is typically a one-pen type, which also digitally displays the process
value. A 100 ohm platinum RTD is used for temperature measurement. It is placed in the discharge air of the
chamber plenum.

The recorder configuration is documented in the Test Report, which is located in the Supplemental
Instructions Section. Reference the recorder’s user manual for a detailed operation of the unit.

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19.0 SEQUENCE OF OPERATION

Important! Make sure the Installation Instructions have been properly followed before operating
the chamber. All switches should be in the OFF position before starting the sequence below.

Chambers Without Watlow 93 TempGard IV Option:

1. Plug the chamber power supply cord into your power supply receptacle. Turn on the power source to

the chamber (Customer supplied disconnect, or circuit breaker). The display of the main controller
should be illuminated.

2. Load product and make sure the door is securely closed.

3. Enter the desired temperature program, or manual setpoints into the main controller.

Important: Check to see if any features or optional equipment must be turned on with an Event Output
from the main controller. If an Event Output were supplied, a Controller Event Output Label with the
Event Output listing would be installed on the side of the chamber. Event Outputs are described either
in one of the various “Option” sections, or in the “Temperature Controller - Conditioning Control
Functions” section for unique applications.

Reference the corresponding ‘Option’ section for a description of any optional feature.

4. Close the Power switch on the main controller panel. The switch green ON light should illuminate. The

conditioner fan will start, and chamber conditioning will begin.

Chambers With Watlow 93 TempGard IV Option:

1. For Model TJR Only: After mounting the TempGard IV box on top of the chamber Make sure you

have connected the RTD wires to the Watlow 93 Controller and have reinstalled the top enclosure to the
TempGard IV unit.

Plug the chamber power cord into the TempGard IV receptacle, which is located on the back of the
TempGard IV enclosure. Plug the TempGard IV power cord into your power supply receptacle. Turn on
the power source to the chamber (Customer supplied disconnect, or circuit breaker).

For Model TUJR Only: Plug the chamber power supply cord into your power supply receptacle. Turn
on the power source to the chamber (Customer supplied disconnect, or circuit breaker).

2. Press the Chamber Power pushbutton on the TempGard IV panel. The Normal light and the displays of

the main controller and the Watlow 93 should be illuminated.

3. Load product and make sure the door is securely closed.

4. Enter the desired temperature program, or manual setpoints into the main controller.

Important: Check to see if any features or optional equipment must be turned on with an Event Output
from the main controller. If an Event Output were supplied, a Controller Event Output Label with the
Event Output listing would be installed on the side of the chamber. Event Outputs are described either
in one of the various “Option” sections, or in the “Temperature Controller - Conditioning Control
Functions” section for unique applications.

Reference the corresponding ‘Option’ section for a description of any optional feature.

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5. Enter the desired high and low limits into the Watlow 93. Refer to the “Alarm and Shutdown Circuit”
description for further details.

6. Close the Power switch on the main controller panel. The switch green ON light should illuminate. The
conditioner fan will start, and chamber conditioning will begin.

Important Note! For complete programming and/or operating instructions on any of the controllers,
electrical / mechanical components, or optional equipment, you must refer to their operating manuals
included with your Tenney Environmental manual.

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20.0 PREVENTATIVE MAINTENANCE

Only qualified service personnel should ever be permitted to perform any service related
procedure on this chamber!

Frequency of preventive maintenance procedures depends upon how the facility is used and upon other
circumstances. Because of this, a hard and fast schedule of maintenance operations is difficult to present.
Indeed, an inflexible schedule might be suitable for one user, but completely inadequate for another.
Therefore, we have provided periodic figures when to perform maintenance procedures, based on the
average chamber use.

We suggest that you maintain a preventive maintenance log. In this log you will record operating notes,
pressures, temperatures, and electric readings. The log is valuable because it will help maintenance and
service people by documenting long term trends and by showing parameter levels when the chamber is
operating properly.

Since the refrigeration system is sealed and the instruments are solid state, little maintenance is required on
the temperature chamber. However, the following preventive maintenance steps are suggested.

20.1 General Maintenance

All interlocks and safety features should be tested periodically for proper operation.

1. For air-cooled refrigeration systems, inspect the condenser coil for dust or dirt accumulation that would
impede the flow of air. A dirty condenser will decrease system efficiency and drive up compressor
head pressure, causing it to trip out. If necessary, clean with a brush or vacuum cleaner. Frequency of
cleaning depends upon the air quality at the chamber.

Period: approx. every 30 days.

2. For water-cooled refrigeration systems, make sure the condenser water supply is according to the
specifications listed on the Refrigeration Drawing. If a closed-loop water supply system is not utilized
and the water-out port connection is to an open drain, make sure that flow to the open drain is not
restricted. Inadequate flow will decrease system efficiency and drive up compressor head pressure,
causing it to trip out. The water supply pressure must be 40 PSI Delta.

Period: approx. every 30 days.

3. Inspect the chamber door gasket. Check to see if the door seals tightly around its perimeter. Replace
gasket if significant wear is evident. If the gasket doesn't show any sign of wear, check the operation of
the door latch. Adjust the door latch if necessary.

Period: approx. every 30 days.

4. Only after disconnecting all power to the chamber, inspect and clean the conditioner fans / blower
wheels, and the condenser fans (air-cooled units). Make sure they spin freely. Make sure that the
conditioner fans / blower wheels are tight on their shafts.

Period: approx. every 6 months.

5. Only after disconnecting all power to the chamber, clean the evaporator coil in the chamber
conditioning plenum.

Period: approx. every 6 months.

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6. Only after disconnecting all power to the chamber, inspect inside the machinery compartment and look
for loose electrical connections, frayed wires, loose components, or other potential problems.

Period: approx. every 6 months.

7. Only after disconnecting all power to the chamber, inspect the electric heaters inside the chamber
conditioning plenum and look for sagging elements, broken insulators, or other defects.

Period: approx. every 6 months.

8. If your chamber has the optional TempGard IV, do the following:

Period: approx. every 6 months.

a) High Setpoint: Dial a temperature well below actual workspace temperature. The instrument must

transfer to alarm state, disabling protected circuits.

b) Low Setpoint: Dial a temperature well above actual workspace temperature. The instrument must

transfer to alarm state, disabling protected circuits.

c) Test the alarm buzzer, making sure it is operable.

d) If customer's contact closure is used to energize an externally powered heat source, make sure

that the contact closure removes power when TempGard IV is in the alarm state.

Important Note: For complete preventative maintenance instructions or equipment maintenance
instructions on any of the instruments, electrical or mechanical components, or electrical / mechanical
machinery and motors, you must refer to their operating manuals included with your Tenney, or Lunaire
Environmental manual. The smaller manuals and vendor cut-sheets are located in the Supplemental
Instructions Section. Any large manuals that could not fit into this 3-ring blue binder are sent alongside of it.

Notes:

♦ The refrigeration system is permanently sealed and a periodic oil change is NOT required.
♦ If a loss of cooling performance is noted, immediately check the condenser for restricted air flow.
♦ All motors are permanently lubricated; therefore, greasing or oiling is not required.

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21.0 SERVICING CASCADE REFRIGERATION SYSTEMS

INTRODUCTION

Note: Only qualified service personnel should ever be permitted to perform any service related
procedure on this chamber!

This information is written to help the refrigeration serviceman trouble-shoot and repair low temperature
cascade systems. It is assumed that the reader is familiar with standard refrigeration practice and is
interested in the special techniques applicable to cascade systems.

Important! Please remember that the following description may differ in some respects to the
refrigeration system equipped with your particular chamber.

History:

Prior to the development of low boiling point refrigerants such as R13 (-114 deg. F) and R503 (-127 deg. F),
reaching ultra low temperatures with mechanical refrigeration was difficult. R22 was used down to -80 deg.
F, but its system had serious drawbacks. Large and cumbersome, the machinery was subject to the many
troubles that afflict a compound system operating at suctions as low as 23 inches of vacuum. The modern
cascade system can reach as low as -120 deg. F with suction pressures of 0 PSIG or higher. Compact,
serviceable, and reliable, today’s cascade system is found on thousands of environmental test chambers.

How It Works:

Two types of popular cascade systems are expansion valve and capillary tube. The system described in this
manual is the capillary tube type.

Refrigerants with low boiling points have correspondingly high condensing pressures at normal ambients.
They cannot be liquefied by conventional air or water-cooled condensing units. Therefore, low temperature
refrigerants are condensed by a separate refrigeration system called “the high stage”. The main job of the
high stage in most cascade systems is to condense low stage refrigerant.

High Stage:

The high stage is a conventional single-stage system having a compressor, air or water cooled condenser,
expansion valve, and evaporator. The evaporator is the cascade condenser, serving the low stage. Modern
systems use R404a in the high stage, making -50 deg. F refrigerant temperature possible at 0 PSIG suction
pressure.

Low Stage:

The low stage is charged with refrigerant in vapor phase only to a specified gauge pressure. When the low­stage is idle with all components stabilized at 70 deg. F, it will contain no liquid refrigerant. When the system
is activated, the low stage compressor will pump hot gas through the discharge line to the de-superheater
(on 1HP units only). The de-superheater (air or water-cooled) removes some heat from the refrigerant gas,
lightening the heat load on the cascade condenser. Leaving the de-superheater, the gas passes through an
oil separator and flows to the cascade condenser. Here it is liquefied by heat exchange with high stage
refrigerant and flows to the expansion valve.

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Cascade Condenser:

The cascade condenser is the high stage system’s evaporator and low stage system’s condenser. It can be
either tube-in-tube with the low-stage refrigerant in the outside tube, or tube-in-shell with the low-stage
refrigerant in the shell.

De - Superheater (only on 1HP units):

The de-superheater consists of coils as part of the high stage condenser with low stage discharge gas
running through them. Its purpose is to remove some heat from the low stage discharge gas and thereby
lighten the load on the high-stage system.

Evaporator Coil:

The evaporator coil is part of the low stage system in which the liquid refrigerant boils or evaporates,
absorbing heat as it changes into a vapor. Refrigerant flow to the evaporator is metered by a capillary tube
type valve.

Capillary Tube:

A capillary tube is a length of tubing of small diameter with the internal diameter held to extremely close
tolerances. It is used as a fixed orifice to meter the proper feed of liquid refrigerant.

Thermostat:

A thermostat TS is mounted on the suction return line near the low stage compressor to monitor the
temperature of the return gas flow. When a predetermined high temperature is reached, the thermostat will
energize the Artificial Loading solenoid 14SOL. The setting is normally 70 degrees Fahrenheit.

Load Limit Switch:

A high pressure cut-in sensor monitors the pressure inside the low stage compressor and will activate the
Load Limit Switch 4PS when the low stage discharge pressure reaches 280 PSIG. This will energize the
Artificial Loading solenoid 14SOL. 4PS will be deactivated when the pressure falls to 240 PSIG.

Artificial Loading:

In response to the Thermostat switch TS or the Load Limit switch 4PS, the Artificial Loading solenoid will
inject liquid refrigerant into the suction side of the low stage. It will first enter the expansion tank where the
added volume permits the charging of additional refrigerant without increasing the standby or charging
pressure beyond workable limits. Refrigerant gas is then sucked out of the expansion tank and metered
through a capillary tube to the suction side of the low stage compressor. This action will maintain a positive
cool refrigerant flow to the compressor, preventing overheating of the compressor and the discharge gas.

Expansion Tank:

An expansion tank is provided to add volume to the low stage. Added volume permits the charging of
additional refrigerant without increasing the standby or charging pressure beyond workable limits. Refrigerant
gas is sucked out of the expansion tank during system operation. It is metered through a capillary tube,
regulating the rate of gas entry into the system.

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Frosted Lines Are Typical:

A low-stage characteristic is frosted liquid and suction lines. In a normal cascade system, the liquid line is
always below +32 deg. F. The suction line, returning from a -100 deg. F evaporator, assuming 15 degree
superheat, will also be far below freezing.

Leak Testing:

Loss of refrigerant is the most common cause of refrigeration failure. Because of temperature extremes
experienced by its metal parts, the cascade system is particularly susceptible to leaks.

Check the entire system with an electronic leak detector. If the system is empty or at low pressure, boost
pressure to 200 PSIG with inert gas (not oxygen) diluted with a percentage of high stage refrigerant. Test
again.

A leak check while the system is at low temperature, -80 deg. F or colder, is a necessity. Expansion valve
flanges, superheat adjustment caps, and other mechanical joints should be tightened and checked for leaks
while at low temperature.

You may use a Halide torch to locate large leaks, but make your final test with the more sensitive electronic
leak detector. This is especially important on the low stage. The low stage is gas charged with a relatively
small quantity of refrigerant. Because of this, small leaks can quickly incapacitate the system.

Testing by Static Charge:

One advantage of a gas charged system is that its tightness can be checked by periodic observation of static
or standby pressure. You must read the pressure with all parts of the system at ambient temperature. This is
important. The unit must be shut down at least 24
hours before a static pressure reading is taken. To eliminate the possibility of cooling the cascade condenser
with the high-stage, pump-down cycle, all power to the unit must be off during the shut down period.

When reading static pressure, consider ambient temperature. Most static charge data are for a 10 deg. F
decrease in temperature. Due to a large system’s considerable thermal mass, several days may be required
for all components to completely stabilize at a particular ambient.

Evacuation:

Granted, refrigerants R23 and R404a are expensive, but there are times when charges must be recovered. A
contaminated system must be cleaned and evacuated regardless of refrigerant expense.

If there is a possibility that moisture, non-condensibles, or the wrong refrigerant contaminated a system,
recover the charge and evacuate.

Select a two-stage pump capable of pumping the system down below 200 microns, and connect an
appropriate gauge to ready system pressure. The ordinary compound refrigeration gauge is inadequate,
however a thermocouple gauge is ideal. Evacuating a leaky system is an exercise in futility. Therefore, make
sure the system is absolutely tight before beginning evacuation.

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Charging a Low Stage:

1. Do not charge liquid into the low stage.

2. Do not charge the system when it is below room temperature.

3. Do not use charging hoses on very high pressure refrigerants or low stage refrigerants. Cylinder

pressure exceeds 500 PSIG.

4. Never charge the unit when it is running.

As you will note from the above, low stage charging procedure differs from the conventional method. Correct
charging pressure will be noted on the equipment nameplate or in the instructions. Remember that it is
important that you charge by pressure, not by volume of refrigerant.

Use 1/4 inch copper tube between refrigerant cylinder and system. Open the cylinder valve very slowly.
Charge into the suction side while closely watching the discharge gauge. When correct pressure is reached,
shut off the refrigerant cylinder valve, allowing the system to equalize from 10 to 15 minutes. If the pressure
drops, crack open the cylinder valve, and slowly raise the pressure. Always take enough time. Systems with
expansion tanks connected by a capillary tube or restrictor valve may need several minutes for gas pressure
to equalize.

Keep the refrigerant cylinder upright when charging. Above all, be careful. Do not over-pressurize.
Disconnect the cylinder immediately when charging is complete. A leaky cylinder valve could continue to
bleed high pressure refrigerant into the system, possibly causing it to rupture. Do not take chances. The
saturation pressures of low temperature refrigerants are extremely high.

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22.0 CHAMBER TROUBLESHOOTING GUIDE

This section does not propose to be a complete and comprehensive troubleshooting guide for the
serviceman. However, it attempts to help you locate the causes of possible troubles so that you can make
simple repairs or adjustments yourself. The information here should also help you in localizing trouble so that
you can better describe the malfunction when contacting the Tenney Service Department. Refer to the
appropriate electrical and refrigeration drawings when using these troubleshooting suggestions.

TENNEY JUNIOR TROUBLESHOOTING GUIDE

PROBLEM POSSIBLE CAUSE CORRECTIVE ACTION

1. Conditioner fan dead

2. Insufficient Heat

3. No Heat

4. Excessive Heat

5. Refrigeration System Dead

Motor shaft frozen Verify - rotate by hand carefully!

Defective motor Verify - feel for heat & measure

current

Chamber door is ajar Close securely

One heater element is burned out Verify - measure current

Controller failure Carefully check programming

Heat Limiter opened Replace

Heater elements burned out, or open Replace

Heat output failing to close Verify - Contact Tenney Service

Triac 1TRC failed open Replace

Open temperature sensor Replace

Triac 1TRC failed in conducting state
(usual failure mode)

Heat output failing to open Verify - Contact Tenney Service

Short circuited temperature sensor Replace

Cooling output failing to close Verify - Contact Tenney Service

Triac 2TRC failing to conduct Replace

Compressor motor overload protector
has tripped

Replace

Wait for 5 minutes. If overload does
not close - replace it

6. Compressor hums but will not

start

7. Repeated shorting or blowing of

start capacitors

Tenney Junior Test Chambers: Models TJR and TUJR, W942, or WF4

Low line voltage Get proper electrical service

Starting capacitor is defective Replace

Compressor relay defective Replace

Internal compressor problem Measure winding resistance, test for

grounds, contact Tenney Service

Excessive start time, voltage too low Correct low line voltage problem

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TENNEY ENVIRONMENTAL

TENNEY JUNIOR TROUBLESHOOTING GUIDE - continued

PROBLEM POSSIBLE CAUSE CORRECTIVE ACTION

8. Compressor starts, hums, runs

slowly, staying on start winding

9. Low stage compressor will not

run

10. Low stage runs, but little or no

cooling

11. Compressor runs but cools

inefficiently

12. Refrigeration works long or

continuously

13. Compressor repeatedly trips

out overload protector

Low line voltage Get proper electrical service

Compressor relay is stuck Replace

Shorted winding Test resistances, test for grounds,

contact Tenney Service

Pressure switch PS2 not closing Contact Tenney Service

Low stage is low on refrigerant Have system leak tested

Artificial loading valve SV stuck open
full time

Main cooling coil badly frosted Raise temperature to defrost

Restricted ventilation, dirty condenser
fins

Excessive heat load Reduce load if possible

Ice on evaporator coil Defrost

Low refrigerant charge Have charge checked by refrigeration

Pressure switch failure Have refrigeration mechanic check

Replace

Move unit away from wall, clean
condenser fins

mechanic - charges are on ID label

switches. Contact Tenney Service

14. Noisy compressors

15. Noisy compressors, even with

secure hold-downs

Compressor loose on mounts Tighten hold down nuts

Broken springs within compressor
housing

Replace compressor - Call Tenney for
assistance

NOTE: At site ambient temperature, if the chamber does not pull down substantially in
temperature within 15 minutes, something is wrong. Turn the chamber off. Let it normalize and defrost.
Then, try it again. If it still does not pull down to low temperature, shut it off and get technical help. A
refrigeration system which does not cool properly should not be run for prolonged periods. It may have a
leak and be low on refrigerant. Since the compressor depends upon cool returning refrigerant for cooling, it
can be overheated when operated in an undercharged system.

Remember that the compressors have internal overloads with automatic reset; these are in addition to circuit
breakers. Therefore, when a compressor cuts out, it must be given time to cool so that its internal protector
has time to reset.

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SUPPLEMENTAL INSTRUCTIONS

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