NuAire 7 Series User manual

OM0123 Page 1 of 68
Rev 15
Water-Jacketed,
US Autoflow Automatic CO2Incubator
Models
NU-4750, NU-4850, NU-4950
NU-4750D, NU-4850D, NU-4950D
NU-4750E, NU-4850E, NU-4950E
Operation & Maintenance Manual
July, 2013
Revision 15
Series 10 4750
Series 5 4750D
Series 10 4750E
Series 11 4850
Series 7 4850D
Series 11 4850E
Series 11 4950
Series 7 4950D
Series 11 4950E
For 115 Vac, 60 Hz Only
Manufactured By:
NuAire, Inc.
2100 Fernbrook Lane
Plymouth, MN 55447
Toll-Free: 1-800-328-3352
In Minnesota: (763)-553-1270
Fax: [phone]

OM0123 Page 2 of 68
Rev 15
Water-Jacketed, US Autoflow
Automatic CO2Incubator
Operation & Maintenance Manual
Models NU-4750/D/E, NU-4850/D/E, NU-4950/D/E
Table of Contents
Section No. 1……………………………….General Description
Section No. 2……………………………….Performance Parameters
Section No. 3……………………………….Models, Features & Specifications
Section No. 4……………………………….Test Performance & Procedures
Section No. 5……………………………….Warranty
Section No. 6……………………………….Shipments
Section No. 7……………………………….Installation
Section No. 8……………………………….US Autoflow Operation
8.1…………………………………Sterility
8.2…………………………………Humidity
8.3…………………………………System Introduction
8.4…………………………………Front Control Panel
8.5…………………………………US Autoflow Rear Panel
8.6…………………………………Run Mode Operator Interactions
8.7…………………………………Setup Mode Operator Interactions
8.8…………………………………Diagnostic Interactions
8.8.1……………………………….Power-Up Self Test
8.8.2……………………………….Diagnostic Mode Test
Section No. 9………………………………..Calibration
9.1…………………………………Chamber Temperature Calibration
9.2………………………………….Door Temperature Calibration
9.3…………………………………Setting Air Injections
9.4…………………………………CO2Calibration
9.5………………………………….Relative Humidity Calibration (NU-4850, 4950)
9.6………………………………….O2Sensor Calibration (NU-4950)
Section No. 10……………………………….Maintaining Your US Autoflow
10.1 .................................................... Shutting Down
10.2 ...................................................... Chemical Decontamination
Section No. 11……………………………….Error Indicators & Troubleshooting
Section No. 12……………………………….Remote Alarm Contacts
Section No. 13……………………………….Electrical/Environmental Requirements
Manual Drawings
BCD-10404...........................................Specification Drawing, NU-4750/4850/4950/D/E/G
ACD-04119...........................................Shelf Installation
BCD-07343, 07344, 07345 ...................Front Panel Labels
BCD-07347...........................................Rear Panel Arrangement
Assembly Drawings
BCD-07346...........................................Front Panel Assembly
BCD-10405...........................................Chamber Tubing Assembly
BCD-10407...........................................Door Heater & Switch Assembly
BCD-07348...........................................Control Center Assembly
BCD-07349...........................................Electrical & Tubing Connections, NU-4750/D/E/G
BCD-07350...........................................Electrical & Tubing Connections, NU-4850/D/E/G
BCD-07351...........................................Electrical & Tubing Connections, NU-4950/D/E/G
Electrical Schematics
BCD-07337 ........................................Electrical Schematic, NU-4750/4850/4950/D/E/G
BCD-07615, 07616, 07617.................Main Control Board Electrical Schematics

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Rev 15
US Autoflow Automatic CO2,
Water-Jacketed Incubator
Models NU-4750/D/E, NU-4850/D/E,
NU-4950/D/E
Operation & Maintenance Manual
1.0 General Description
The NuAire US Autoflow Automatic CO2water-jacketed Incubator has been designed to provide a reliable controlled in
vitro environment for optimum tissue cell culture growth. The chamber also provides an environment for the storage
and preservation of gametes and animal tissue cell cultures at on near body temperature. Six parameters contribute to
optimum growth conditions. These are:
1. Humidity
2. Precise temperature control
3. Precise CO2control
4. Sterility
5. Precise O2control
6. Reliability
Like all NuAire equipment, the US Autoflow has been designed to provide the highest quality standards of performance
with matching computer technology, precise temperature control and CO2gas control system combining state-of-the-
art technology with years of design, quality and manufacturing experience.
In order to accomplish the foregoing objectives, the US Autoflow features the following:
1.1 Extra Large (20 gallon) Water-Jacket - Each Chamber
The outer stainless steel wall is lined with a space-age insulation providing a R5.0 rating, minimizing heat loss.
The large 20 gallon (75.7 liters) water-jacket utilizes water, one of natures best "sinks" of heat. Its high
capacity to hold heat makes it the ideal medium to surround a chamber in order to obtain temperature
uniformity. In fact, the ability of materials to hold heat, called the specific heat, uses water as the
comparative standard. The large water-jacket surrounding the chamber permits the water to circulate within
the jacket, producing a temperature uniformity of ±0.2°C. The larger the mass, the less susceptible the
environment within the chamber is to environment fluctuations outside. It also adds cabinet stability for the
growth of vibration sensitive cells.
1.2 NuAire Incubator Control Electronics
The NuAire Incubator Control Electronics (NICE) is a state-of-the-art microcomputer based control system
specifically designed to service the precise control requirements of the chambers environment, providing
optimum programmable conditions for culture growth. The microcomputer is "user friendly" with status
indicators, LED display of control parameters, Hidden key and three touch control key pads to permit efficient
operator entry of data.
The microcomputer is supported with Read Only Memory (ROM) containing executable software, Random
Access Memory (RAM) for temporary storage and Electronically Erasable Programmable Read Only Memory
(EEPROM) for control set points and parameters. The EEPROM provides for indefinite storage of these values
during periods of power off or power interruption (power fault tolerant).
The microcomputer includes a complete internal diagnostic software package that permits fault isolation
detection down to the failed component.

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1.3 CO2Display and Control
The NuAire US Autoflow employs a solid-state single gas analyzer for carbon dioxide. This innovative analyzer
utilizes a filter correlation technique for non-dispersive infrared analysis of CO2. The analyzer consists of an
optical bench incorporating an infrared source, sample cell, and infrared detector. The amount of power
radiating on the detector is an approximate logarithmic function of the CO2concentration in the gas between
source and detector. Detector linearization is performed with 32-bit digital accuracy. The measurement of
CO2is independent of humidity and temperature variations within the chamber.
1.4 All Stainless Steel Construction
The US Autoflow's exterior is constructed of 16 gauge, type 304L stainless steel with the interior being 16
gauge, type 304L polished stainless steel using coved corner construction, which provides an easily cleanable
(for decontamination) inert surface that does not promote biological growth. All exposed edges are deburred
to insure no sharp edges. The exterior is finished in a textured polyurethane finish, which is resistant to
chemicals and easily cleaned using mild household detergents. In addition all shelves, shelf supports and
guide rails are easily removable and can be autoclaved to remove contamination.
1.5 Relative Humidity Display and Control (NU-4850, NU-4950)
Conventionally, humidification of the chamber is achieved through the process of water evaporation from a
water reservoir pan placed in the chamber. The NU-4850 & NU-4950 models humidify the chamber by
injecting a heated water vapor from a reservoir located outside of the chamber. This gives the operator
control over the amount of humidity in the chamber from below ambient to 95%. After a door opening, the
recovery time to 95% +3% is 10 minutes on average with all settings at default values. The control system has
a +3% accuracy from any given setpoint.
The control system uses a solid-state capacitance humidity sensor to monitor the relative humidity within the
chamber. If humidity is required, the control system will activate solenoid valve. The pump will then draw
chamber air to itself, through a humidified heated enclosure and returned to the chamber. The control will
continue until the setpoint is achieved. The relative humidity display and control option offers an accurate
and reliable method to control humidity when required.
1.6 O2Display and Control (NU-4950)
The US AutoFlow has an available optional Oxygen display and control system. The system controls from 21%
(ambient level) down to 2%. The recovery time from ambient to 5% ±2% is typically less than 10 minutes.
The accuracy is ±1% from any given set point.
Oxygen sensor is a fuel cell type, which generates a linear mVDC signal based on O2content in the chamber.
The sensor is unaffected by CO, H2and various acidic gases such as CO2, H2S, NOx, SOx, etc.
A sensor automatic monitoring is provided to monitor the O2sensor as fuel cell depletes. The automatic
monitoring occurs every 24 hours and lasts 2 minutes. During automatic monitoring events, all the displays
are locked on existing reading. Control keys are also locked. At this time, air inject valve is energized to draw
fresh air through the O2sensor. A new O2span value is stored in memory for use as the 21.0% of O2reference
point. During automatic monitoring, the new span value in mV is also compared with original voltage outputs.
If the current output is less than 70% of original output, an “RPL” replace message is indicated on the O2
display.

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1.8 Safety Instructions
These safety instructions describe the safety features of the INVITROCELL Incubator.
The incubator has been manufactured using the latest technological developments and has been thoroughly
tested before delivery. It may, however, present potential hazards if it is not used according to the
intended purpose or outside of operating parameters. Therefore, the following procedures must always be
observed:
• The incubator must be operated only by trained and authorized personnel.
• For any operation of this unit, the operator must prepare clear and concise written instructions for
operating and cleaning, utilizing applicable safety data sheets, plant hygiene guidelines, and
technical regulations, in particular.
o Which decontamination measures are to be applied for the incubator and accessories?
o Which protective measures apply while specific agents are used?
o Which measures are to be taken in the case of an accident?
• Repairs to the device must be carried out only by trained and authorized expert personnel.
• Keep these operating instructions close to the unit so that safety instructions and important
information are always accessible.
• Should you encounter problems that are not detailed adequately in the operating instructions, please
contact your NuAire Representative or NuAire technical Services.
1.9 Explanation of symbols
Symbol Description
Safety alert symbol indicates a potentially hazardous
situation which, if not avoided, could result in death
of serious injury.
CAUTION
!
Safety alert symbol indicates a potentially hazardous
situation which, if not avoided, may result in minor or
moderate injury.
WARNING
!
Note:

Biohazard
Hazardous Gases!
Personal Protection Equipment Required.

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Rev 15
CAUTION
Hot Surface
Burn Potential
Chemical Hazard
Ground, Earth
!
Flammable Hazard
Attention accompanies information or
important symbol
Potential electrical hazard,
only qualified person to access.
Lead Free
CAUTION used without the safety alert symbol
indicates a potentially hazardous situation which, if not
avoided, may result in property damage.

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2.0 Performance Parameters
2.1 Each chamber's water-jacket holds 20 gallons (75.7 liters) of water that, in conjunction with the
microcomputer control system, provides an interior chamber temperature uniformity of ±0.2°C at 37.0°C.
2.2 The US Autoflow's microcomputer temperature control system has two temperature sensors: one in the
water jacket and one in the chamber. The chamber temperature sensor compares the values to a setpoint
and executes a time proportional control algorithm that energizes a solid-state switch, supplying power to the
heater.
2.3 The CO2 percentage is controlled by a solid-state infrared gas analyzer which provides accurate monitoring of
CO2, regardless of changes in temperature or humidity within the chamber.
2.4 Calibration of the infrared CO2gas analyzer is accomplished simply through a front panel diagnostic procedure
to assure accuracy and minimize downtime.
2.5 Automatic recovery of CO2to 5.0 +0.2% CO2within 3-1/2 minutes after a door opening at default control,
inject and delay settings.
2.6 The outer door includes a radiant heater in order to minimize condensation on the inner glass door. A
magnetic outer door gasket helps to insure a tight seal against the cabinet.
2.7 The inner glass door is 3/16 inch (5mm) tempered with smooth-ground edges and seals are tight against a
removable U-grooved silicone rubber gasket. The door latch is cam action. A solid-state magnetic switch
monitors door motion.
2.8 All electronic controls are modular and easily removed through the front or side service control center.
2.9 All control electronics are protected with a circuit breaker that will trip at 145% of load rating in less than
2 seconds. Should the circuit breaker open (pop-out button will appear), merely depress to reset.
2.10 A water fill access port is provided on the front of the US Autoflow. Removal of a ¼ inch NPT plated brass fill
plug allows filling using a ¼ inch NPT hose adapter (provided).
2.11 The US Autoflow has factory installed adjustable leveling legs to compensate for uneven laboratory surfaces.
2.12 The entire interior shelving assembly is easily removable for decontamination. Shelves and brackets are
constructed from 18 gauge, type 304 polished stainless steel.
2.13 A thru-wall access port is provided for operating electrical appliances such as roller apparatus, rockers, etc.
2.14 A CO2sample port is provided on the front panel to check the concentration of CO2in the chamber.
2.15 A water level sensor is provided to monitor the level of water within the jacket.
2.16 A water-jacket valve is provided on the bottom of the unit for ease of draining.

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3.0 Models, Features & Specifications
NuAire offers various Water-Jacketed US Autoflow Automatic models:
• NU-4750/D/E*: TEMP/CO2Display and Control
• NU-4850/D/E*: TEMP/CO2/RH Display and Control
• NU-4950/D/E*: TEMP/CO2/RH/O2Display and Control
*D: 100VAC/50-60Hz
*E: 230VAC/50-60Hz
3.1 Weight (lbs. /kg - per unit): NU-4750/D/E NU-4850/D/E NU-4950/D/E
Dry: 222 / 101 232 / 105 232 / 105
Operational (RH system & jacket filled) 392 / 178 412 / 188 412 / 188
Shipping: 291 / 132 301 / 137 301 / 137
3.2 Dimensions (see also Specification Drawing BCD-07342)
Overall Dimensions - inches (mm):
All Models
Width:
31.00 (787.40)
Height:
34.00 (863.60)
Depth:
25.50 (647.70)
Shelf Capacity:
Size: 19.25 Inches (489mm) x 19.25 Inches (489mm)
Supplied: 4 Shelves
Max. Capacity: 20 Shelves
Max. Weight Capacity: 30 lbs (Do not slide shelf out with more than 20 lbs on it.)
Water Pan:
Dimensions: Mean Length 18.00” (457mm)
Mean Width 18.00” (457mm)
Depth 1.250” (38mm)
Capacity: Maximum Capacity 7.75 Liters
Recommended Fill 6.5 Liters
3.3 NU-4750 Standard Features
•100% stainless steel chamber construction
•Large capacity water-jacket (20 gallon) (75.7 liters)
• Temperature Control System (Default Set-Point 37.0°)
•Chamber Temperature Range: 18°C to 55°C (5°C above ambient to 30°C ambient max.)
•Chamber temperature uniformity: ±0.2°C at 37°C
•Temperature sensitivity: ±0.0125°C
• CO2Control System (Default Set-Point 5.0%)
•CO2Range: 0-20%
•CO2Accuracy: ±0.1%
•CO2Recovery to 5.0 ±0.2%: Less than 3 minutes
•Remote Alarm Output Contacts

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3.4 NU-4850 Additional Features
• RH Control System (Default Set-Point 90%)
• RH Range: Ambient to 95%
• RH Accuracy: +3%
• RH Recovery to 95% +3%: 10 minutes *
3.5 NU-4950 Additional Features
• O2Control System (Default Set-Point 21%)
• O2Range: 2-21%
• O2Accuracy: +1%
• O2Recovery to 5% +2%: 10 minutes *
Note: All recovery ratings are at default control & option settings.
3.6 Standard Items Packed with Unit
•(4) Stainless Steel Shelves
•(8) Stainless Steel Shelf Brackets
•(4) Stainless Steel Shelf Bracket Supports
•(1) Full Size Water Pan with Supports (supplied with all units)
•(1) Fill Port Hose Adaptor
•(1) Fill Port Plug
•(1) Gas Tube with Filter
•(1) 6 feet (2m), Fill Tube
•(1) Electrical Cord 8 foot (2.5m)
•(1) Operation & Maintenance Manual
•(1) Operating Instructions
3.7 Optional Features
•Model Number I01Automatic CO2Tank Switch (Internal)
•Model Number I09Automatic N2Tank Switch (Internal)
•Model Number I11Internal Coil for Chilled Water
•Model Number I18RS-232 Communications Interface
•Model Number I44Chart Recorder Multi-Signal Outputs
Consult factory for additional accessories (Order Separately)

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4.0 Test Performance & Procedures
All equipment is thoroughly inspected by NUAIRE at the time of shipment. Quality control is maintained by constant
surveillance over each product, beginning at the receipt of purchased material and concluding with a final inspection
before packing. In all instances where product quality cannot be easily assessed on the end item (i.e. water-jacket leak
tightness), the product is inspected during sub-assembly fabrication. The following test procedures are conducted on
each cabinet and a copy of the test report is included with each unit.
4.1 Visual Inspection
4.1.1 Each US Autoflow is visually inspected to insure that the interior is clean and free from scratches, nicks,
and burrs, and that all welds, both interior and exterior, are ground and polished smooth.
4.1.2 Painted surfaces are inspected to be free of scratches, nicks, insufficient covering and runs.
4.1.3 The doors open and close freely without binding of the hinges.
The gasket seals the inner glass door tightly. The glass door is free of scratches.
4.2 Electrical Tests
4.2.1 Electrical Leakage Test
All Autoflow Incubators may not exceed 0.5 milliamperes in the normal running mode and may not
exceed 3.5 milliamperes in a single fault condition (ex. open ground).
4.2.2 Dielectric Voltage
All Autoflow Incubators are required to withstand 1770 VDC (2150 VDC for 230 VAC units) between
dead metal parts and the hot/neutral power source leads with no electrical breakdown.
This is factory tested using Associated Research Model 520L and 7564SA.
4.2.3 Grounding Continuity
The resistance between the green bonding conductor of supply cord and any dead metal part of the
cabinet shall not exceed 0.10 ohms.
4.3 Functional Tests
The following functional tests are performed on every unit at the end of a continuous 48-hour burn in period.
4.3.1 Control Systems
All diagnostic functions are exercised to insure proper operation of control systems, components and
alarms.
4.3.2 CO2Control
Each unit is calibrated to function at 5%. CO2is introduced into the chamber and allowed to stabilize for
ten minutes at 5% concentration.
The concentration is checked with an independent measuring instrument.
Each unit is monitored during the 48-hour burn in period and only accepted with zero failures.
4.3.3 CO2Recovery
Each unit is exercised for CO2recovery time at the end of the 48-hour burn in period.
The door is opened for 1 minute to deplete the CO2.
After the door is closed, the unit shall recover to 5.0 +0.2% within 3-1/2 minutes.

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5.0 Warranty
NuAire, Inc. warrants that it will repair F.O.B. its factory or furnish without charge F.O.B. its factory a similar part to
replace any material in its equipment within 24 months parts and labor after the date of sale if proven to the
satisfaction of the company to have been defective at the time it was sold provided that all parts claimed defective shall
be returned, properly identified to the company at its factory, charges prepaid. Factory installed equipment or
accessories are warranted only to the extent guaranteed by the original manufacturer and this warranty shall not apply
to any portion of the equipment modified by the user. Claims under this warranty should be directed to NuAire, Inc.
setting forth in detail the nature of the defect, the date of the initial installation and the serial and model number of the
equipment.
NuAire, Inc. warrants the water jacket and will repair or replace F.O.B. its factory or furnish without charge F.O.B. its
factory the water-jacket within five years after the date of sale if proved to the satisfaction of the company to have
been defective at the time it was sold.
This warranty shall not apply to any NuAire product or part thereof, which has been subject to misuse, abuse, filling the
water-jacket improperly, using additives in water-jacket, accident, shipping damage, improper installation or service, or
damage by fire, flood or acts of God. If the serial number of this product is altered, removed or defaced as to be
illegible, the warranty shall be null and void in its entirety.
The warranty is for the sole benefit of the original purchaser and is not assignable or transferable. Prior to returning
any item, for any reason, contact NuAire for a Return Authorization Number. This number must accompany all returns.
Any product shipped to NuAire without this number will be returned, refused shipment, or collect freight.
6.0 Shipments
NuAire, Inc. takes every reasonable precaution to assure that your Incubator arrives without damage.
Motor carriers are carefully selected and shipping cartons have been specifically designed to insure your purchase.
However, damage can occur in any shipment and the following outlines the steps you should take on receipt of a NuAire
Incubator to be sure that if damage has occurred, the proper claims and actions are taken immediately.
6.1 Damaged Shipments
6.1.1 Terms are F.O.B. factory, unless stated otherwise.
Therefore, it is important to check each shipment before acceptance.
6.1.2 If there is visible damage, the material can be accepted after the driver makes a notation on the
consignee's copy of the freight bill.
Then an inspection must be made to verify the claim against the carrier.
This inspection is the basis of your filing the claim against the carrier.
6.1.3 If concealed damage is found, it is absolutely necessary to NOTIFY THE FREIGHT AGENT AT ONCE, and
request an inspection. Without this inspection, the transportation company may not accept a claim for
loss or damage. If the carrier will not perform the inspection, an affidavit must be prepared stating that
he was contacted on a certain date and that he failed to comply with the request. This, along with
other papers in the customer's possession, will support the claim.

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7.0 Installation
The US Autoflow is fastened to the base skid and it is usually the best procedure to leave the skid attached until the US
Autoflow is located in its approximate position, to facilitate ease in handling. The base skid can then be removed by
removing the four bolts holding the cabinet to the skid. Examine the US Autoflow carefully. INSPECT both the exterior
and the interior of the US Autoflow for any transit damage before discarding the shipping crate (see Section 6.1.3).
7.1 Location
In locating the US Autoflow, consider all possible conditions that might affect its performance, as well as
laboratory procedures for its intended purpose. Do not locate near heating or cooling ducts, or next to
equipment that generates heat (steam radiators, stoves, ovens, autoclaves, etc.). Avoid direct sun rays and
rapidly moving air currents. The US Autoflow needs even heat loss on all surfaces in order to maintain an
internal temperature variation of less than 0.2 degrees C. As a result, a minimum of 2 inches (50 mm) must
be allowed between the rear and sides of the US Autoflow and any walls, partitions or obstructions to
facilitate adequate convection of air around the US Autoflow's water-jacket. For maintenance/service
purposes, the control center side containing the electronics should remain accessible.
7.2 Leveling
The US Autoflow should be leveled prior to filling the water, and should rest firmly on the bench or floor.
Uneven water levels may cause false "Low Water" indications on the front panel as well as to affect the water
circulation paths within the water-jacket, which could cause condensation on the walls of the chamber.
Leveling feet are provided for this purpose, factory installed into the base of the US Autoflow. Turning the
adjustable leveling feet counter-clockwise raises the US Autoflow. The leveling feet height should be
approximately ¼ inch (6 mm) below the US Autoflow Base.
7.3 Spring Pump Assembly Shipping Foam
The spring pump assembly contains a piece of foam packing used to immobilize the pump during shipping:
IMPORTANT: FOAM MUST BE REMOVED BEFORE OPERATION! To access, first remove the side access
cover. After popping front control panel open, grasp foam from end and carefully remove. It may be saved
for any future shipping. Close front control panel and replace side access cover and screws.
7.4 Shelf & Water Pan Installation
Before installation of the shelves, NuAire recommends to decontaminate all surfaces within the interior
chamber, glass door and outer door with gasket. They can be wiped down with a disinfectant of 70 percent
alcohol or similar non-corrosive anti-microbial agent.
Provided with each US Autoflow are four shelves.
The shelves are easily installed per Drawing ACD-04119, by attaching the guide supports to the stainless steel
pins in the interior of the chamber. Additional shelves and shelf guides are available.
The water pan is installed on two shelf guides at the bottom of the shelf rack.

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7.5 Electrical
The electrical supply circuit to the US Autoflow must conform to all national and local electrical codes.
Consult the US Autoflow's serial-data plate, located on the upper corner of the right side of the Incubator, for
voltage, cycle, phase and ampere requirements before making connection. Plug the power cord securely into
a grounded power source. VOLTAGE SHOULD NOT VARY MORE THAN 5% FROM SERIAL PLATE RATINGS. A
separate branch circuit is recommended to prevent possible loss of product due to overloading or failure of
other equipment on the same circuit. A SURGE PROTECTOR IS STRONGLY RECOMMENDED to avoid power-
related faults.
7.6 Precaution for US Autoflow Filling
To prepare the US Autoflow for filling, turn on main power switch located on back panel and set mode switch
to setup. The digital indicator should light up as well as the low water light.
7.7 Filling & Draining the Water-Jacket
The fill port plug is located on the front top left side behind the exterior door. Install the fill port fitting.
Place the tubing over the adapter and connect the other end to either a funnel or serrated tap.
Use single distilled water, NO PURER THAN 1 MEGA OHM.
Fill the water jacket until the "LOW WATER" light turns off.
Add an additional 3 to 4 liters of water, remove the tube adapter, and replace with the fill port plug.
CAUTION
Be sure to position and level the US Autoflow as desired before filling with water.
DO NOT OVERFILL!
The water jacket requires no anti-bacterial agents. The US Autoflow already incorporates a copper tube
producing copper sulfate which eliminates bacterial growth within the water jacket. ABSOLUTELY NO
CHLORINATED OR HALOGEN MATERIALS ARE TO BE USED IN THE WATER JACKET.
A safety overfill port is located next to the fill port plug so if overfill does occur, the water will be relieved
through the port.
The can be drained from the drain plug located on the bottom left side. The drain uses a ball valve to control
the drain water. If the valve stem is horizontal, the drain is closed and if it is vertical, the drain is open. A
white safety plug must be removed prior to draining located on the bottom of the ball valve. It also insures
no leakage will occur. (See figure top of next page)
-
CAUTION
ONLY USE SINGLE DISTILLED
WATER NO PURER THAN 1 MEGA

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7.8 Air Inlet Connection
An air inlet tubing kit consists of one foot clear vinyl tube and (1) 50mm polypropylene .3 micron HEPA filter.
Locate the air inlet port on the back panel of the unit. Remove cover cap, connect one end of tubing to the
air inlet port, and the other end of tubing to the air filter.
CAUTION: This is a free air supply. DO NOT CONNECT to pressurized source.
7.9 CO2/N2* Tube Connection
Included with every US Autoflow is a tubing kit consisting of (1) six foot (2 m) vinyl tube and (1) 50 mm
polypropylene 0.3 micron HEPA filter. *for NU-4950 Model
7.9.1 CO2/N2Supply
1. Before the CO2/N2supply is turned on to the US Autoflow, fill the water jacket and set the
temperature (See Section 8.7.1.).
CAUTION: CO2/N2Pressure to the US Autoflow is rated at 20 PSIG or 1.4 BAR.
Do not exceed 25 PSIG or 1.8 BAR
2. CO2/N2of medical grade is recommended.
3. A two-stage pressure regulator, Linde #19590 (NU-1564), or equal, is recommended.
4. DO NOT USE a single stage regulator.

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7.9.2 CO2/N2Pressure Regulators
The regulator's high-pressure stage, direct from supply cylinder must have a range of 0 to 2000 PSI or
0 to 140 BAR. This gauge indicates actual tank pressure. The low-pressure stage should have a range
of 0 to 30 PSI or 0 to 2 BAR (100 PSI or 6 BARS maximum). This gauge will indicate the actual CO2/N2
pressure into the US Autoflow system. Some single stage CO2/N2pressure regulators have two
gauges. USE A TWO STAGE REGULATOR. All NuAire Autoflow's use CO2/N2in such small quantities
that precise metering of CO2input pressure is important for maximum performance of the US
Autoflow.
To connect the regulator: First, open the CO2/N2cylinder slightly for an instant (this is termed
"cracking the valve"). This will blow out dust or dirt that may have collected in the valve outlet. BE
SURE to keep your face away from the valve outlet to protect your eyes from dust or dirt. Second,
MAKE SURE the regulator pressure-adjusting screw is released by turning it counterclockwise until it
turns freely. Third, attach the regulator to the cylinder valve and tighten the connection nut with a
wrench. BE SURE DISC GASKET IS IN PLACE BEFORE MAKING CONNECTION.
7.9.3 CO2 /N2Connection
High concentration of CO2/N2 gas can cause asphyxiation! Install Incubator in well ventilated area.
This Incubator is designed to be operated with CO2/N2gas only.
Connecting a flammable or toxic gas can result in a hazardous condition.
Gases other than CO2/N2 should be not connected to this equipment.
CO2gas cylinders have a UN1013 label on the cylinder and are equipped
with a CGA 320 outlet valve.
Check the gas cylinder for the proper identification labels.
Do not use CO2gas cylinders equipped with siphon tubes. A siphon tube is used to extract liquid CO2
from the cylinder which can damage the pressure regulator. Consult with your gas supplier to ensure
that the CO2cylinder does no contain a siphon tube.
Connect the CO2& N2supply from the low-stage of the two-stage regulator to the inlet fitting located
on the Incubator back panel. The filter should be inserted downstream of the low-stage regulator
before the inlet nozzle to the US Autoflow. Observe proper flow orientation of the filter (look for "in"
on filter). The tubing is easily cut with a sharp knife.
7.9.4 CO2/N2Supply Adjustment
With the regulator OFF (i.e. fully counterclockwise), open the cylinder valve slowly-usually 1 to 2 turns
is sufficient.
NEVER STAND IN FRONT OR BEHIND THE REGULATOR WHEN OPENING THE VALVE.
ALWAYS STAND TO ONE SIDE.
The cylinder tank pressure should read: 700 to 800 PSI (48 to 55 BAR) for CO2 or 2550 to 2650 PSI
(176 to 183 BAR) for N2more or less depending on the temperature of the cylinder. Next turn the
regulator's pressure adjusting screw clockwise until the low-pressure gauge reads 20 PSI or 1.4 BAR.
The CO2connection is now complete.
NOTE: OSHA requires the CO2/N2tanks to be physically restrained (i.e. via chained to wall) to prevent
accidental damage to cylinder.
If optional feature Model Number I01/I09, CO2/N2Automatic Tank Switch (Internal) is purchased;
separate installation instructions are provided.

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8.0 US Autoflow Operation
CAUTION: All maintenance actions on this equipment must be performed by a qualified technician who is
familiar with the proper maintenance procedures required for this equipment, as well as repair.
The US Autoflow is designed to provide a sterile, constant temperature and high humidity controlled atmosphere for
optimum growth of tissue cell cultures or other organisms requiring this precise environment. To operate the US
Autoflow properly, the following parameters must be reviewed, carefully set and/or prepared.
8.1 Sterility
The environment provided by the US Autoflow is not selective. As a result, any contamination within the
chamber is subjected to the same environment as the specimens. Therefore, before placing any cultures in
the US Autoflow, the shelves, and shelf brackets should be sterilized. The interior side-walls, top, bottom,
door, as well as the gasket should be wiped clean with a 70% solution of isopropyl alcohol or other
disinfectant, to remove any contamination. Use mild detergent to clean exterior of US Autoflow.
8.2 Humidity
Humidification of the US Autoflow Model NU-4750 Series is achieved through the process of water
evaporation (vapor pressure) from a stainless steel water pan (NuAire Model NU-1555) placed near the
bottom of the US Autoflow shelf rack. Materials of different thermal resistance (i.e. glass, plastic) do not offer
sufficient thermal recovery and are not recommended for use. Although some metals offer better thermal
coefficients than stainless steel, dissimilar metals cause electrolysis in the acid atmosphere (carbonic acid)
and should never be used, or placed within the US Autoflow's chamber.
USE ONLY DISTILLED WATER, NO PURER THAN 1 MEGAOHM in the stainless steel pan.
The water should be changed at least once a week, preferably more often. FLOODING THE BOTTOM OF THE
US AUTOFLOW IS NOT RECOMMENDED since it is difficult to change the water weekly and almost
necessitates the use of chemicals which are not recommended and may damage the stainless steel. It also
promotes condensation on the US Autoflow's inner walls because it steals the natural convection, heat flow
through the inner chamber and condensation points occur.
ABSOLUTELY NO CHLORINATED OR HALOGEN MATERIALS ARE TO BE USED IN THE CHAMBER.
Humidity recovery will be back 95% within 15-20 minutes after a 30 second door opening with a water
reservoir area of 361 square inches (i.e. a NU-1555 full-sized pan). Contamination in the water pan may be
avoided by adding a small amount of copper sulfate to it after each decontamination of the chamber.
Condensation on the door walls, top or bottom of the chamber indicates the door heat duty cycle setting is
too high and should be corrected by calibration (see Section 9.2).
The US Autoflow – Models NU-4850 & 4950 series are provided with relative humidity display and control
system, most of the above can be applied with the exception of the water pan. The RH Reservoir, located on
the left side of the unit, can be monitored for water level visually. Use only single distilled water,NO PURER
THAN 1 MEGA OHM to fill the reservoir. The relative humidity control system will control any given setpoint
between ambient and 95% RH. The alarm setpoints are preset at 5% over the setpoint and not being able to
reach the setpoint to within 5% after 4 hours.
191
!
ATTENTION ACCOMPANY'S
INFORMATION OR IMPORTANT
SYMBOL
POTENTIAL ELECTRICAL
HAZARD ONLY QUALIFIED
PERSON TO ACCESS
188

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The relative humidity control system is programmed with a Humidity Control alarm system. The HC alarm
system is designed to prevent the uncontrolled injection of humidity into the Incubator chamber.
Uncontrolled injection has two primary causes. The easiest one to detect is a bad or disconnected RH sensor.
If the measured output voltage of the humidity sensor falls outside of the normal range, an HC alarm is
declared without delay by the control board. This portion of the HC alarm system is not selectable, and is
active any time the RH control system is enabled.
A second option menu selectable part of the humidity control alarm system was designed to detect an RH
sensor that is out of calibration or not responsive. During an RH recovery, if the inject solenoid is engaged for
too long, or if it cycles on and off too many times without reaching setpoint, an HC alarm is declared. The
length of time or the number of cycles that a solenoid turns on before an alarm declaration is user adjustable
(see Section 8.8.4 for the user selectable portions of the system). This portion of the humidity control alarm
system is also inhibited by a cold evaporator box signal sent via a snap disc thermostat mounted on the
evaporator box. It is also inhibited by a low reservoir water level signal sent via a float switch in the reservoir.
Both conditions will light the yellow LED labeled RH reservoir.
No matter what event triggers an HC alarm, the alarm sequence is always the same. First an alarm is sounded
(with audible and visual clues) and the RH evaporator box heat is turned off. After 2-1/2 hours, the air-inject
solenoid opens and will run for a period of one half hour. At this time (three hours from alarm declaration),
the air solenoid turns off, and the RH inject solenoid turns on and stays on until the alarm is cleared. This
gives the user some humidity in the Incubator, but prevents the continuous, uncontrolled injection of hot
water vapor. Temperature and gas control are unaffected by humidity control alarms (see Section 11 Error
Indicators & Troubleshooting for identifying and responding to the humidity control alarm indicators. Read
section 9.4 before determining the RH set-point and/or calibrating the system.
8.3 System Introduction
The NuAire Incubator Control Electronics (NICE) system is designed to service the control requirements of the
US Autoflow Incubator chamber. Temperature and CO2level are controlled by preset values to provide
optimum conditions for culture growth within a chamber. Operator input is coordinated through the control
panel keypad and status displays. Below figure shows the various inputs and outputs of the system.

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The NuAire Incubator Control Electronics is a state-of-the-art microcomputer based system that provides:
8.3.1 Single chamber control in a single electronic package.
8.3.2 Enhanced information presentation of the following:
•Chamber temperature (set point and actual)
•CO2level (set point and actual)
•Humidity level (set point and actual) (NU-4850 & NU-4950)
•Humidity/O2level (set point and actual) (NU-4950)
•Output and alarm status:
 Water Jacket Heater Status
 CO2Control Status
 Water-Jacket Low Water Status
 Door Ajar Status
 System Alarm Condition Status
 Optional, CO2Tank Selection
 RH Control Status (NU-4850 & NU-4950)
 RH Reservoir Tank Status (NU-4850 & NU-4950)
 O2Control Status (NU-4950)
 Optional, N2Tank Status (NU-4950)
8.3.3 Simplified Operator Controls. The control panel is operated using five keypads, run/setup key,
Up/Down arrow keys, Select key and Hidden key (NuAire logo). The run/setup key controls the
Incubator's two modes, Run or Setup. To change modes, press and hold the run/setup key for three
seconds. If in Run mode, the green LED above the run/setup key should be on solid. If in Setup mode,
the green LED above the run/setup key should be blinking, as well as the temperature and CO2displays
indicating "SETUP". In the Run mode, the unit is fully functional with all control/alarms activated. In the
Setup mode, the unit is inactive, no control/alarms exists. The Select key controls the current active
parameter. As the Select key is repeatedly depressed, the corresponding green LED next to the
parameter will indicate the parameter which is active. Each depression advances to the next
parameter. The Up or Down arrow keys are used for setpoint parameter changes by depressing the Up
or Down arrow key when the selected parameter is activated. As Hidden key is pressed, it allows access
to diagnosis, option and reset modes.
Password Protection - The US Autoflow has the ability to offer password protection of the setup
parameters. By activating the password function in the option configuration parameters (Section 8.8.4),
the use of the Up, Down, and Select keys are required in the correct order to access the set up mode.
8.3.4 Automatic notification of abnormal situations.
The red alarm LED on the control panel indicators will light to indicate a fault within the system.
Such faults include:
•System intermittent
•Temperature Control Fault
(Temperature exceeds set point by more than 1.0°C or does not reach to setpoint within 4 hours)
•CO2Control Fault
(CO2exceeds set point by more than 1.0% or doesn't reach setpoint within 30 minutes)
•Humidity Control Fault
(Relative humidity exceeds set point by more than 5.0% or doesn't reach setpoint within 4 hours)
•O2Control Fault
(O2exceeds set point by more than 5.0% or doesn't reach setpoint within 1hour)