NuAire BLIZZARD NU-99729VFT User manual

OM0300
Series A
Revision 2
April 2022
NuAire, Inc.
2100 Fernbrook Lane
Plymouth, MN 55447
Toll-Free: 1-800-328-3352
Minnesota: [phone]
Fax: [phone]
NUAIRE BLIZZARD ULTRA LOW TEMPERATURE
VARIABLE FREQUENCY TOUCHSCREEN FREEZER
NU-99729VFT
SERVICE MANUAL

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Table of Contents
1.0 Features of the Product................................................................................................................ 3
1.1 Main Functions and Features of the Product ..................................................................................... 3
2.0 Product Details ............................................................................................................................ 3
2.1 Temperature Control .......................................................................................................................... 3
2.2 Safety Control ..................................................................................................................................... 3
2.3 Refrigeration system........................................................................................................................... 3
2.4 Practical design ................................................................................................................................... 4
2.5 VIP ....................................................................................................................................................... 4
2.6 Temperature monitoring function...................................................................................................... 4
2.7 Noise ................................................................................................................................................... 4
3.0 Parts of the Freezer...................................................................................................................... 5
3.1 Freezer Overview ................................................................................................................................ 5
3.2 Inner Door Components ..................................................................................................................... 6
3.3 Electrical Components ........................................................................................................................ 8
3.4 System Structure............................................................................................................................... 12
4.0 Process Overview........................................................................................................................14
4.1 Administrator Permission ................................................................................................................. 14
4.2 Precautions ....................................................................................................................................... 19
5.0 Technical Parameters..................................................................................................................20
6.0 Preventive Measures, Product Use and Daily Maintenance ..........................................................21
6.1 Principle of Ultra-Low Temperature Frequency Conversion Refrigeration ...................................... 21
6.2 Use Method of Ultra-Low Temperature Cabinet .............................................................................. 21
6.3 Working Principle of Pressure Switch ............................................................................................... 22
6.4 Characteristics of Refrigerant ........................................................................................................... 22
6.5 Filling Process of Refrigerant ............................................................................................................ 22
7.0 Refrigeration Schematic and Wiring Diagram...............................................................................25
7.1 Refrigeration Diagram....................................................................................................................... 25
7.2 Wiring Diagram ................................................................................................................................. 26
8.0 Control System ...........................................................................................................................27
8.1 Control of Compressor...................................................................................................................... 27
8.2 Control of Fans.................................................................................................................................. 29
8.3 Battery Control.................................................................................................................................. 29
8.4 Heating Wire Control ........................................................................................................................ 31
8.5 USB Data Download .......................................................................................................................... 31
8.6 Remote Alarm Function .................................................................................................................... 31
9.0 Installation and Disassembly Process...........................................................................................32
9.1 Installation Location.......................................................................................................................... 32
9.2 Handling and Removal of Packaging Materials................................................................................. 32
9.3 Moving the Unit ................................................................................................................................ 33
9.4 Removal of Display Cover ................................................................................................................. 34
10.0 Troubleshooting and Frequently Asked Questions .......................................................................35
10.1 Problems and Possible Solutions ...................................................................................................... 35
10.2 Troubleshooting Table ...................................................................................................................... 36
10.3 High Alarm Processing Method ........................................................................................................ 39
10.4 Low Alarm Processing Method ......................................................................................................... 40
11.0 Diagram and Spare Parts List .......................................................................................................41

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1.0 Features of the Product
1.1 Main Functions and Features of the Product
1. The application range of the ultra-low temperature cabinet is -40℃to -86℃.
2. The freezer is designed to balance the internal and external pressure of the cabinet, allowing ease of opening
and closing the door.
3. The Microprocessor, 10-inch LCD screen, and the digital display screen can simultaneously display the
temperature inside the cabinet, the setting temperature, the ambient temperature, and the input voltage.
4. Users can set high and low temperature alarm, temperature inside the cabinet, ambient temperature alarm,
user login, inquiry and download data of temperature curve, event record, alarm record, and running status.
5. Multiple fault alarms (high and low temperature alarm, sensor alarm, condenser dirty alarm, excess ambient
temperature alarm, door opening alarm, low battery power alarm, power outage alarm).
6. Two alarm modes (beep alarm, light flashing alarm) and start-up delay protection (start-up delay time can be set
by user's requirement).
7. Network functionality as well as an RS-485 data interface to connect to a computer to display the temperature
inside the cabinet and the alarm information through the computer, and can control the temperature and
monitor whether the equipment is normal.
8. 5V power supply output function, which allows the user to directly supply power to the cold chain module.
9. Remote alarm functions and can connect the alarm to other rooms.
10. The standard USB data storage module supplied with the product can store high and low temperature set, actual
temperature, ambient temperature, and voltage inside the cabinet for more than 10 years.
11. The freezer is supplied with 2 standard 25.5mm test ports.
12. Equipped with casters which are flexible, movable, lockable, supported, and can be adjusted as required.
13. Available options include: a chart recorder, network monitoring system, electromagnetic lock, card punching
module.
14. The LCD screen comes with Wi-Fi module and can connect wireless network to entry sample library function
(optional) to manage sample easily.
2.0 Product Details
2.1 Temperature Control
Computer controlled, temperature digital display, regulating unit of 0.1 ℃, and the application temperature
range of -40 to -86 ℃.
2.2 Safety Control
1. Multiple fault alarms (high and low temperature alarm, sensor alarm, condenser dirty alarm, excess ambient
temperature alarm, door opening alarm, low battery power alarm, power outage alarm).
2. Two alarm modes (buzzing alarm, light flashing alarm and prompt box alarm), start-up delay protection (start-up
delay time can be set by user's requirement).
3. All independent components have safe grounding.
2.3 Refrigeration system
1. Intelligent frequency conversion cascade refrigeration technology, imported brand compressor, strong
refrigerating capacity, environment-friendly refrigerant, no fluorine, zero emission.
2. High-density insulated combined cabinet body design, made of VIP special thermal insulation material, with
good thermal insulation effect.

OM0300 PAGE 4OF 42 REV 2APRIL/2022
3. Independent multi-layer sealing structure and thermal insulation system design, which can effectively eliminate
frosting phenomenon.
4. Specially designed computer control, which can automatically select the optimal compressor start-stop scheme
according to the set temperature and the use environment to reduce the noise and improve the efficiency.
2.4 Practical design
1. LCD display screen, which can display the temperature inside the cabinet, set temperature, ambient
temperature, input voltage, can set high and low temperature alarm and the temperature inside the cabinet,
and have the function of fault prompt and early warning.
2. Adjustable shelf design to facilitate access of goods.
3. Safety door lock, designed with double locks (one padlock and one key built-in lock), to prevent the opening
without permission.
4. Integrated innovative handle design and compact caster design, flexible and convenient.
5. With the function of network and remote alarm, advanced and practical.
6. Unique 5V power supply module, which solves the user's trouble in pulling-down the power supply separately
and is directly powered by 5V output of the whole machine.
2.5 VIP
PU foaming layer + VIP vacuum thermal insulation material is adopted, which reduces the floor area of
equipment to the maximum extent at the time of thermal insulation.
2.6 Temperature monitoring function
1. The alarm information of the equipment can be sent to the registered mobile phone users in the form of short
messages.
2. The actual operating temperature inside the cabinet can be downloaded through the USB data storage module;
2.7 Noise
Unique intelligent compressor start-stop control, enabling lower noise, leading in the world and comfortable
working environment.

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3.0 Parts of the Freezer
3.1 Freezer Overview
LCD Touchscreen
Door Handle
(With Lock)
Component
Access Panel
Leveling Leg
Caster

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3.2 Inner Door Components
Inner door handle: When
replacing, remove the side
screws of the handle.
Outer door handle
Balance valve
Integrated cabinet
opening
Sealing strip of outer
door: take
out from the
retaining groove when
replacing.
Inner door: PU
foaming structure
Sealing strip of inner
door: take out from the
retaining groove when
replacing.
Air-inlet grill

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Fixed cover for main
internal temp.
sensor.
Mounting clip for
stainless-steel shelf.
Zinc-coated inner
liner.
Trim strip of cabinet
shelf.
Back threaded
hole
Test port 1
Test port 2
Engine compartment
guard plate, right side
Power switch cover
plate
Inner door
gasket seal
5V cold chain
Pressure
balancer
Foam core inner
door.
Outer door gasket
seal
Magnetic open door alarm
switch box
Engine compartment
guard plate, left side

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3.3 Electrical Components
Inner door handle
Threaded hole at back of cabinet
body, four-way structure
Test port
Power cord plug
loT module
Main control
panel
Backup system
board
Switching power
supply
Remote alarm wiring
Condenser fan
Lithium battery
485 communication
module port
Power switch
Thermocouple plate
Battery switch
Electric control
box
Filter
Line bank
Signal wire of loT
module, connected to
signal wire terminal of
control board
Power supply cable of IOT module,
connected with switching power supply, red
wire connect with +V, black wire connect
with -V

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Main Control Panel
5V cold
chain
Backup system
Electro-
magnetic lock
Electro-
magnetic lock
Display
panel
Balancing
hole
Condenser sensor
Condenser sensor
Ambient temp.
sensor
Master
sensor
Remote alarm
Loading
plate
Fan/heating wire at
cabinet opening
Strong electric
power supply
CN2:
Punch-card board
CN5:
USB driven board
Switching
power supply
Battery
Networking
Networking
Variable frequency
signal line
3-color
lamp
Printer
Door
switch
Thermocouple
plate
CN1:
Display panel signal line
connector
Display Panel

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Thermocouple Board
exit of low stage evaporator
entrance of low stage evaporator
exit of low stage condenser
exit of high stage condenser
Main control
panel
entrance of high stage condenser
Connect Main board
Main sensor
Backup system power supply line（option）