MVE Variō Technical Manual Rev A

MVE Biological Systems

PN 14930250 REV A, MVE Variō Technical Manual

MVE Variō Technical Manual

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MVE Variō Technical Manual

MVE Biological Systems

1.0 PREFACE

MVE Variō Pro TECHNICAL MANUAL PN 14930250 – Rev. A January 2011

Chart Inc. 2200 Airport Industrial Drive, Suite 500 Ball Ground, GA 30107

Customer / Technical Service: The Americas Chart BioMedical Phone: 770-721-7759 ● Toll Free 1-800-482-2473 Fax: 770-721-7758 or 1-888-932-2473 [email protected] Email: [email protected] Japan Chart Japan Co., Ltd. Phone: +(03) 5776 2670 Fax: +(03) 5776 2676 Email: [email protected] Asia, Australia, & Pacific Rim Chart Australia Pty Ltd. Phone: +61 (2) 974 94333 Fax: +61 (2) 974 94666 Email: [email protected] Europe Chart BioMedical Ltd. Phone: +44 (0) 1344 403100 Fax: +44 (0) 1189 799245 [email protected] Email: [email protected] This manual covers the use and maintenance of MVE Variō Series Freezers and the associated MVE Variō Pro control system. It is intended for use by trained personnel only. READ BEFORE USING THIS EQUIPMENT. All service and maintenance should be performed by an authorized MVE Distributor.

NOTE: All MVE models are Class 1, externally powered, continuous operation medical devices. They are not suitable for use with flammable anesthetics. This equipment has been tested and found to comply with the limits for medical devices to IEC 601-1-2: [or EN 60601010102:2001 or Medical Device Directive 93/42/EEC].

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2.0 TABLE OF CONTENTS 1.0 PREFACE ... 2 2.0 TABLE OF CONTENTS ... 3 3.0 SAFETY ... 5 4.0 CERTIFICATIONS & LISTINGS... 7 5.0 PRODUCT INFORMATION ... 8 5.1

MVE VARIŌ SERIES MODELS & SPECIFICATIONS ... 8

5.1.1

Physical Dimensions ... 8

5.1.2

Maximum Storage Capacity... 9

5.2

VARIŌ PRO CONTROLLER ... 10

5.2.1

Display Panel Identification ... 10

5.2.2

Connection Panel Identification ... 11

5.2.3

Variō Pro Specs, Outputs, & Connections ... 12

5.3

MVE VARIŌ OPERATING ENVIRONMENT ... 15

6.0 INSTALLATION & STARTUP... 16 7.0 SYSTEM OPERATION ... 19 7.1

Introduction ... 19

7.2

The Hot Gas Bypass Cycle ... 20

7.3

The Cooling Cycle... 20

7.3.1 7.4

Coil Outlet Temperature ... 20

Cooling Cycle Termination ... 20

7.5

Variō Pro Recommended Temperature Settings ... 21

7.6

Variō Pro Default Settings ... 21

7.7

Variō Pro System Alarms ... 22

7.7.1

Alarm Definitions ... 22

7.7.2

Remote Monitoring of System Alarms ... 24

7.8

System Security ... 25

7.9

Battery Backup... 26

7.10

Lid Switch ... 26

7.11

Communications & Networking ... 27

7.11.1

HyperTerminal ... 28

7.11.2

ChartConnect 3000 ... 32

7.11.3

Printer Setup ... 33

8.0 SYSTEM SETUP & CUSTOMIZATION... 34 8.1

Temperature Settings ... 34

8.1.1

Temp Sensors A & B ... 34

8.1.2

Chamber Temperature / Coil Outlet Temperature & Deadband ... 35

8.1.3

Inlet Temperature & Bypass Cycle ... 36

8.1.4

Setting Liquid Nitrogen Temperature ... 37

8.2

Battery Backup... 38

8.3

Lid Switch ... 39

8.4

Controller Display & Output ... 40

8.4.1

Temperature Units ... 40

8.4.2

Alarm Buzzer ... 40

8.4.3

Language Settings ... 41

8.4.4

Printer Settings ... 41

8.5

Security Setup ... 42

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8.5.1

Password Entry Mode ... 42

8.5.2

Global Password ... 42

8.5.3

Multilevel Passwords ... 43

8.6

Advanced Settings ... 44

8.6.1

Date & Time Adjustment ... 44

8.6.2

Communications ... 45

8.6.3

Unit ID / Modbus Menu ... 46

8.6.4

Restoring Manufacturer Defaults ... 46

8.6.5

Restarting the Controller ... 47

9.0 MVE VARIŌ PRO MENU MAPS ... 48 9.1

Setup Menus ... 48

9.2

Temperature Menus ... 48

9.3

Temp A & B Menus ... 49

9.4

Inlet Temp Menus ... 49

9.5

Cooling Temp Menus ... 50

9.6

Calibration Menus ... 51

9.7

Add-on Menus ... 52

9.8

Display & Output ... 52

9.9

Advanced Settings ... 53

9.10

Password Menus ... 54

9.11

MVE Variō Pro Display Screens... 55

9.11.1

Power Up & Main Displays ... 55

9.11.2

Alarm & Status Displays ... 55

10.0 PREVENTATIVE MAINTENANCE & TROUBLESHOOTING ... 56 10.1

Preventative Maintenance Schedule ... 56

10.2

Preventative Maintenance Procedures ... 57

10.2.1

Calibrating the Pt1000 Temperature Sensors ... 57

10.2.2

Testing the Remote Alarm Contacts ... 59

10.2.3

Plumbing Leak Check... 60

10.2.4

Variō Pro Firmware Update ... 60

10.2.5

Verifying Adequate LN2 Supply ... 60

10.2.6

High Temperature Alarm Test ... 61

10.2.7

Lid Thaw Procedure ... 62

10.2.8

Folding Step Inspection ... 62

10.2.9

Filter Replacement ... 62

10.2.10

Relief Valve Replacement ... 62

10.2.11

Complete MVE Variō Pro Function Test ... 62

10.2.12

Solenoid Valve Replacement... 63

10.2.13

Lid Gasket Replacement ... 64

10.2.14

Complete Freezer Thaw & Moisture Removal ... 64

10.3

Accessories & Replacement Parts ... 65

11.0 EN COMPLIANCE TABLES ... 66 12.0 APPENDIX ... 69 12.1

ASCII Interface & Command Index ... 69

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3.0 SAFETY

READ BEFORE OPERATING THIS EQUIPMENT 3.1 INTRODUCTION Liquid nitrogen (LN2) is used in MVE Cryogenic Freezers as a refrigerant. Understanding and following certain safety precautions is extremely important when handling LN2 and the associated cryogenic containers. Nitrogen is a colorless, odorless, tasteless gas. Gaseous nitrogen makes up about 78% of the Earth’s atmosphere by volume. Once collected and isolated, nitrogen can be liquefied. Properties of Nitrogen Boiling Point @ 1 atm -195.8°C , -320.3°F , 77.4 K Thermal Conductivity (Gas) 25.83 mW/(m∙K) Heat of Vaporization (Liquid) 198.38 kJ/kg Density @ 1 atm (Liquid) 1.782 lbs/L , 807.4 g/L , 808.6 kg/m3 Operation of the MVE Variō Series Freezer and the associated MVE Variō Pro controller should be done in accordance with the manufacturer/supplier instructions. It is important that all safety precautions written herein and on the vessel itself be followed.

WARNING 

Nitrogen is a potential asphyxiant and can cause rapid suffocation without warning. Store and use in area with adequate ventilation. DO NOT vent container in confined spaces. DO NOT enter confined spaces where gas may be present unless area has been well ventilated. If inhaled, move to fresh air. If breathing is difficult, supplemental oxygen may be required. If not breathing, give artificial respiration. SEEK MEDICAL ATTENTION IMMEDIATELY.



Liquid nitrogen can cause severe frostbite to the eyes or skin. DO NOT touch frosted pipes or valves. Cold nitrogen vapor can damage the eyes or skin. In case of frostbite, consult a physician immediately. If a physician is not readily available, warm the affected area with water that is near body temperature.



NEVER place LN2 in a sealed container without a pressure relief device. The expansion ratio of liquid nitrogen to gaseous nitrogen is approximately 1 to 700 (i.e. 1 cubic foot of LN2 becomes 700 cubic feet of gas when evaporated).



The two most important safety aspects to consider when handling LN2 are adequate ventilation and eye and skin protection. Although nitrogen gas is non-toxic, it will displace oxygen in a normal breathing atmosphere. Liquid products are of even greater threat since a small amount of liquid evaporates into a large amount of gas. Therefore, it is imperative that cryogenic supply and storage vessels be stored and operated in well ventilated areas.



Persons transferring LN2 should make every effort to protect the eyes and skin from accidental contact with liquid or cold vapor. Chart MVE recommends the following protective clothing and accessories when transferring LN2 or handling hoses, valves, and plumbing components: 

Cryogenic gloves (loose fitting)



Full-face shield or chemical splash goggles



Cryogenic apron



Long sleeve shirt and cuff-less pants



Closed toe shoes

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3.2 RECOMMENDED FIRST AID Every site that stores and uses LN2 should have an appropriate Material Safety Data Sheet (MSDS) present. The MSDS may be obtained from the manufacturer/distributor and will specify the symptoms and treatment of over-exposure to liquid or gaseous nitrogen. A typical summary is shown below: 

If symptoms of asphyxia such as headache, drowsiness, dizziness, excitation, excess salivation, vomiting, or unconsciousness are observed, remove to fresh air. If breathing is difficult, supplemental oxygen maybe required. If breathing has stopped, CALL A PHYSICIAN IMMEDIATELY.



If exposure to cryogenic liquids or cold vapor occurs, restore tissue to normal body temperature (98.6°F, 37°C) as quickly as possible and protect the injured tissue from further damage. Rapid warming of the affected area(s) is best achieved by bathing in warm water. The temperature of the water used should not exceed 140°F, 40°C. Under no circumstances should the affected area be rubbed or otherwise agitated in any way, either before or after warming. If the eyes are affected, flush them thoroughly with warm water for a minimum of 15 minutes. In the event of a massive exposure, remove clothing while showering with warm water. The affected individual should not drink alcohol or smoke. CALL A PHYSICIAN IMMEDIATELY.

3.3 EQUIPMENT USAGE Cryogenic containers must be operated in accordance with the manufacturer/supplier instructions. Safety instructions will also be posted on the side of the vessel. Cryogenic containers must be kept in a wellventilated area protected from weather and away from heat sources. In applications utilizing a modular liquid cylinder as a source of LN2, the supply will need to be replenished at regular intervals to ensure proper operation of the freezer. When exchanging liquid cylinders, follow the below procedure: 1. Allow all plumbing components to warm to room temperature before attempting to change supplies. 2. Close all valves associated with the liquid supply cylinder. 3. Relieve pressure in the plumbing assembly by pressing the manual override button at the bottom of the Variō Pro controller. 4. Loosen the plumbing connection for the transfer hose at the liquid cylinder. 5. Remove empty liquid cylinder and replace with full liquid cylinder pressurized to 22 - 35 psig (1.52 2.41 bar). 6. Attach the transfer hose to the plumbing connection on the liquid cylinder. Ensure that the hose is connected to the connection labeled LIQUID. 7. Tighten the transfer hose connection at the liquid cylinder. 8. Open the liquid supply valve on the liquid cylinder. 9. Inspect plumbing for audible and visual leaks. Repair if necessary. 10. Manually initiate a cooling cycle to verify proper operation.

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4.0 CERTIFICATIONS & LISTINGS All fully automated Chart MVE cryogenic freezer systems equipped with MVE Variō Pro controllers are UL / C-UL listed and CE marked to the Low Voltage Directive (LVD). Specially designated freezer models are also CE marked to the Medical Device Directive (MDD). The LVD is a European Union directive regulating the construction and operation of electrical equipment that is not considered a medical device. The MDD is a European Union directive regulating medical device construction and operation. These listings and certifications are not limited to the electronic controller alone, but encompass the entire freezer system as a whole.

M.D.D. Representative: Medical Product Services Borngasse 20 35619 Braunfels, Germany

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5.0 PRODUCT INFORMATION 5.1

MVE VARIŌ SERIES MODELS & SPECIFICATIONS

Chart MVE offers a wide range of fully automated LN2 freezers that can accommodate a variety of inventory systems designed to meet all of your cryogenic storage needs. Each MVE Variō Series freezer is a hand-made, double-walled, vacuum insulated stainless steel Dewar designed to maintain an internal temperature anywhere from -50°C to -150°C with minimal energy costs and environmental impact. The physical dimensions and storage capabilities for each model are as follows:

5.1.1

Physical Dimensions MVE Variō 1536P

MVE Variō 1539R

MVE Variō 1879P

MVE Variō 1881R

Inner Diameter, in. (mm)

38.5 (978)

38.5 (978)

56.0 (1422)

54.8 (1391)

Lift-over Height, in. (mm)

37.1 (944)

37.1 (944)

40.2 (1021)

38.8 (985)

15.50

15.50

25.22

29.67

7760

7760

17465

18398

Minimum Ceiling Height, in. (mm)

83.2 (2115)

83.2 (2115)

90.3 (2294)

88.9 (2257)

Minimum Door Width, in. (mm)

42.0 (1067)

42.0 (1067)

60 (1524)

60 (1524)

Neck Opening, in. (mm)

17.5 (445)

17.5 (445)

25.0 (635)

25.0 (635)

Overall Height, in. (mm)

61.3 (1556)

63.3 (1607)

62.1 (1577)

61.3 (1556)

Usable Internal Height, in. (mm)

28.8 (732)

30.8 (782)

29.5 (749)

29.5 (749)

Weight Empty, lbs. (kg)

690 (313)

690 (313)

1606 (728)

1721 (781)

Max. Floor Loading Pressure, kPa (Caster base area)

Max. Point Pressure per Caster (kPa)

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5.1.2

Maximum Storage Capacity MVE Variō 1536P

MVE Variō 1539R

MVE Variō 1879P

MVE Variō 1881R

36400

39200

79950

81900

Number of 100 Cell Box Racks

24

24

54

60

Number of 25 Cell Box Racks

16

16

30

12

Number of Boxes Per Rack

13

14

13

13

Total Capacity

3080

3064

5866

5628

Bags / Frame

7

8

7

7

No. of Frames

440

383

838

804

Total Capacity

4338

4338

8622

9414

Bags / Frame

9

9

9

9

No. of Frames

482

482

958

1046

Total Capacity

1488

1736

2952

2940

Bags / Frame

6

7

6

6

No. of Frames

248

248

492

490

Total Capacity

496

812

1584

1608

Bags / Frame

4

4

4

4

No. of Frames

124

203

396

402

Total Capacity

812

608

1104

1240

Bags / Frame

4

4

4

4

No. of Frames

203

152

276

310

Total Capacity

608

496

960

984

Bags / Frame

4

4

4

4

No. of Frames

152

124

240

246

Total Capacity

256

256

504

544

Bags / Frame

4

4

4

4

No. of Frames

64

64

126

136

1.2 & 2.0 ml Vials (Internally Threaded): Total Capacity

Blood Bags:

791 OS/U (25ml)

Compact (25ml)

4R9951 (50ml)

DF200 (200ml)

4R9953 (250ml)

4R9955 (500ml)

DF700 (700ml)

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5.2

VARIŌ PRO CONTROLLER

5.2.1

Display Panel Identification

Display Panel Identification Key Front Panel

The front panel is the user interface for the Variō Pro. All displays and controls are located on the front panel.

Display

A 4 x 20 Liquid Crystal Display (LCD) shows the value of all current conditions. The display also shows any current alarm conditions that may exist.

FOG CLEAR

Used to manually clear the fog from the storage area to increase visibility.

END CLEAR

Used to manually end the fog clear process.

SETUP

Used to adjust the value of all user adjustable functions including Temperature Alarms, Passwords, Etc.

ALARM MUTE

Used to silence the audible alarm. Also used to reset the latching alarm after the alarm condition is corrected. Used to increase number values in setup menus. Press once to decrease incrementally. Hold the button down to scroll quickly. Also be used to toggle YES/NO or ENABLED/DISABLED values. Used to decrease number values in setup menus. Press once to decrease incrementally. Hold the button down to scroll quickly. Also be used to toggle YES/NO or ENABLED/DISABLED values.

ESC

Short for escape, this button is used to exit any menu or setup function.

ENTER

Used to select any menu for editing or save any user setting.

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5.2.2

MVE Variō Technical Manual

Connection Panel Identification

TEMP A TEMP B 30VDC INPUT SERIAL I/O MANUAL FILL SENSOR/ALARM OUTPUT

GLOBAL REMOTE

MAIN WIRE HARNESS

Connection Panel Identification Key Platinum RTD connection for primary sensor Platinum RTD connection for auxiliary sensor Connection for main power supply. RS-485 input/output connection Manual override button, forces cooling valves open Output connection for the remote monitoring of Temp A & various alarm conditions. Output connection for the remote monitoring of all alarm conditions. Any Variō Pro system alarm will cause the NC, NO contacts to switch state. These connections may be wired to any remote monitoring system utilizing normally closed (NC) or normally open (NO) contacts. Connection for main wire harness. All system components are wired through this connection, with the exception of Temp A, Temp B, and the main power supply.

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5.2.3

Variō Pro Specs, Outputs, & Connections

Physical Dimensions Length 9.1 in. (232 mm) Width 3.5 in. (89 mm) Height 8.0 in. (203 mm) Weight 6.5 lbs. (2.95 kg)

Type Size Resolution Keypad

Display Liquid Crystal Display (LCD) with backlight 20 x 4 Character 8 x 5 Pixels per Character 8 keys, Multi function

Electrical Specs MVE Variō Pro Input Voltage Input Current (max.) Input Current (continuous) Power Consumption (max.) Power Consumption (continuous) Solenoid Valve Output Voltage Short Protection

30 VDC 5A 1A 28 W 8W 24 VDC Current limiting, automatic reset

Jerome Power Supply (WSL730M V1) Input Voltage 110-230 VAC, automatically switching Input Frequency 50-60 Hz Output Voltage 30 VDC Current Capability (max.) 3A Input Current 0.73 A @ 110 VAC, 0.35 A @ 230 VAC Power Requirements (Variō Pro + Power Supply) Continuous Input Current < 0.1 A @ 110 VAC Maximum Input Current

0.3 A @ 110 VAC 8W 30 W

Continuous Input Power Maximum Input Power

Physical Connections Temperature Probes 2-pin twist lock Input Power 5-pin DIN Main Wire Harness 15-pin AMP Serial I/O Port RJ-45, 4-pin RS-485 4-20mA & Alarm Output DB15 Global Alarm Contacts Clamp Connection

Type Quantity Resistance Sensitivity Resolution Accuracy Range

Temperature Sensors 2-wire Platinum RTD (Pt1000) 4 1000 Ω @ 0°C 3.85 Ω / °C 0.1°C (0.2°F) Single Point Calibration: ± 1.0°C (1.8°F) Two Point Calibration: ± 2.0°C (3.6°F) - 200°C to 70°C (- 328°C to 158°F)

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MVE Variō Pro Outputs Port / Connection + Main Wire Harness PINS 10 & 11 (Bypass Valves) + Main Wire Harness PINS 4 & 5 (Cooling Valves) DB15, PIN 1 (Analog Temperature) DB15, PIN 6 (High/Low Temp Alarm) DB15, PIN 7 (Lid Open Alarm) DB15, PIN 13 (Valve Stuck Open/Closed Alarm) Global Remote (Normally Closed) Global Remote (Normally Open)

Output +24VDC, 1.5A +24VDC, 1.5A 4-20mA scaled from -200C to 20C Discrete Contact, Isolated Open Collector – Max: 24VDC, 100mA Discrete Contact, Isolated Open Collector – Max: 24VDC, 100mA Discrete Contact, Isolated Open Collector – Max: 24VDC, 100mA 230VAC, 1A max 230VAC, 1A max

Main Wire Harness PIN

Description

1 2 3 4 5 6 7 8 9 10 11 12

Battery Backup 24VDC + Battery Backup 24VDC Lid Switch 1 Cooling Valves 24VDC + Cooling Valves 24VDC Lid Switch 2 Cooling Temp Sensor + Cooling Temp Sensor Inlet Temp Sensor + Bypass 24VDC + Bypass 24VDC Inlet Temp Sensor -

Function (I/O) Input/Output Input/Output Input Output Output Input Input Input Input Output Output Input

DB15 Connection PIN

Description

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Analog Temp + 1 Analog + Not Used Not Used Not Used High/Low Temperature Alarms (NO) Lid Open Alarm (NO) Sensor Failure Alarm (NO) Analog Temp 1 Analog Not Used Not Used Stuck Valve Alarm (NO) +5VDC (Supplied) Common

Function (I/O) Output Output Output Output Output Output Output Output -

1

Circuit is connected, but unassigned.

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Serial I/O Port PIN

Description

1 2 3 4 5 6 7 8

TXA (Transmit +) TXB (Transmit -) Ground Ground RXA (Receive +) RXB (Receive -) No Connection Ground

PIN 1 2 1 2

MVE Variō Technical Manual

1

Function (I/O) Output Output Input Input -

Chamber Temp Sensors Function Description (I/O) Chamber Temp A + Input Chamber Temp A Input Chamber Temp B + Input Chamber Temp B Input

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Global Remote Alarm Function Description PIN (I/O) 1 Normally Closed Output 2 COM Output 3 Normally Open Output 1 All Global Alarm connections are nonpolarity sensitive, latching, dry contact relays with an output of 230VAC at 1A.

Main Power Supply (30 VDC) Function PIN Description (I/O) 1 Ground 2 Chassis Ground 3 28VDC Input 4 NC 5 NC -

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MVE Biological Systems

5.3

MVE Variō Technical Manual

MVE VARIŌ OPERATING ENVIRONMENT

5.3.1 Ambient Temperature & Relative Humidity MVE cryogenic freezers are designed to be operated in environments near room temperature (65°F – 80°F, 18°C – 27°C) and with a relative humidity below 50%. However, a small variance of a few degrees outside of this range will not have a significant impact on the performance of the freezer. The relative humidity should be maintained low enough to keep condensation build up to a minimum, as elevated humidity levels can lead to excessive condensation and frost on and around the lid. In situations where the relative humidity is high and uncontrollable, the lid should be routinely wiped dry to prevent the formation of ice. Should significant ice formation develop, refer to the Preventative Maintenance procedures included with this document for thawing instructions. 5.3.2 Thermal Load MVE Variō Series freezers use LN2 as the refrigerant and do not employ any type of mechanical refrigeration. Therefore, the thermal load will be negligible to negative.

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6.0 INSTALLATION & STARTUP This section will review the basic receiving, installation, and startup procedures for MVE Variō Series freezers. Always inspect the bill of lading for accuracy and external crate/packaging for damage before accepting the shipment. Included with each MVE Variō Series unit: 

Literature Packet 

MVE Variō Pro Quick Start Reference Guide – PN 14910831



Manual Freezer Status Log – PN 10936355



Warranty Statement / Registration / Certificate



MVE Variō Pro Controller (Packaged in a separate box) – PN 14911278



6’ Transfer hose (Inside freezer) – PN 9713109



Desiccant bag (Inside freezer. To be removed and discarded.)



Liquid Nitrogen handling instructions



MVE Checklist (Signed by shipping inspector)

Note: To avoid injury or damaging the equipment, do not apply power to the MVE Variō Pro controller, connect a battery backup, or connect an LN2 supply to the freezer until setup is complete.

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Installation Procedure: Following the careful uncrating and unpacking of the freezer, install using these basic instructions: 1. Ensure all of the plumbing assembly connections to the MVE Variō Pro wire harness are secure. 2. Connect the 12-pin wire harness to the MVE Variō Pro wire harness connection.

3. If the freezer is equipped with battery backup, the included battery fuse must be installed before connecting the battery to the main wire harness. Open the battery enclosure and unscrew the fuse harness. Install the fuse and close the fuse harness and the battery enclosure.

NOTE: Do not connect the battery backup to the main wire harness until setup is complete. 4. Connect Temp A & B temperature sensors to the corresponding twist-lock connection.

5. Plug in the power supply to an appropriate wall outlet with the proper AC voltage. Avoid wall outlets that are connected to emergency generator power if possible. Although an uninterruptible power supply (UPS) is ideal, a surge protector or power conditioner is recommended. 6. If applicable, connect the battery backup to the main wiring harness. While running on outlet power, the MVE Variō Pro supplies a steady 27 VDC trickle charge to the battery backup. The battery backup may need to be charged for several hours before it is able to power the MVE Variō Pro.

7. It is recommended that empty inventory system components such as racks, boxes, frames, or canisters be introduced prior to initiating the first cooling cycle. This will allow the racks, frames, etc. to cool with the freezer. 8. Remove the cap-plug from the fill tee on the plumbing assembly and connect the LN2 supply. If a modular LN2 cylinder is being utilized as the liquid supply, securely connect and tighten the transfer hose to both the fill tee connection and the supply connection labeled LIQUID. If a bulk LN2 supply system is employed, securely connect and tighten the supply connection to the freezer fill tee connection.

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NOTE: The recommended LN2 supply pressure is 22-35 psig (1.52 - 2.41 bar). 9. Plug the power supply into the MVE Variō Pro 30 VDC power input. The MVE Variō Pro display should illuminate and begin the startup sequence.

10. Following the startup sequence, the MVE Variō Pro will start to alarm and initiate a cooling cycle. This is normal. 11. Press ALARM MUTE to silence the audible buzzer for 30 minutes. For installation and startup purposes, the alarm buzzer can be disabled; however, it is recommended that it be re-enabled when installation is complete. 12. Ensure that freezer lid is closed and open the LN2 supply valve. 13. The initial cool-down cycle will take significantly longer than subsequent cooling cycles, and excessive condensation / ice buildup on the lid and plumbing can be expected. However, it is important that the lid not be removed during this period. 14. When the freezer reaches the chamber temperature set point minus the chamber deadband, the Variō Pro will terminate the cooling cycle. The frost and ice buildup will melt and evaporate soon thereafter, and normal operation will commence.

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7.0 SYSTEM OPERATION Efficient offset neck and hinged lid design maximizes vacuum insulated surface area to maintain consistent temperature profile, even with the lid open.

Advanced controller

MVE

Variō™

Pro

Interior heat exchange system: LN2 flows through heat exchangers and the vaporization energy provides low-cost refrigeration

Rotating interior tray allows easy access to freezer samples

Low maintenance and long lasting doubled-walled, vacuum steel insulated, all-stainless construction

Two-tier folding step provides lowest liftover height

Durable casters 7.1

Introduction

MVE Variō™ Series freezers operate using an innovative, patent-pending refrigeration system utilizing liquid nitrogen (LN2) as the sole refrigerant. When a cooling cycle is initiated, LN2 flows from the supply source and through a heat exchanger located beneath the top head of the freezer, making use of the principle of evaporative cooling to maintain ultra-low to cryogenic storage temperatures. This heat transfer system was developed by MVE to fully utilize the heat capacity of LN2 while simultaneously purging frost and moisture from the storage space. The MVE Variō Pro controller monitors and meters the amount of LN2 flowing through the heat exchanger to maintain the completely dry storage space within ±5°C of the user-defined storage temperature, which can be set anywhere from -50°C to -150°C. The efficient offset neck design and double-walled, vacuum insulated, all-stainless steel construction provides a consistent temperature profile throughout the storage space – even with the lid open. While the lid is open, the MVE Variō™ automatically compensates by shortening the cooling cycle interval so that the storage space temperature does not increase above of the desired range. A schematic of the Variō Pro plumbing is shown below, and may be used as reference for the sections that follow.

Bypass Valve PN 14224611S Bypass Muffler PN 11499812 Bypass Muffler Deflector PN 11885449 Cooling Valves PN 14224611S Inline Filter PN 11648945

Pressure Relief Valve (50 psi, 3.45 bar) PN 1810032

PN 14930250 REV A, MVE Variō Technical Manual

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