Nidek Medical Mark5 Nuvo User manual

Nidek Medical Products, Inc®
Mark5 Nuvo® [M5C5] Oxygen
Concentrator Service Manual
Nidek Medical Products, Inc. 3949 Valley East Industrial Drive
Birmingham, Alabama 35217 USA
Telephone: [phone] • 24-Hour Fax: [phone]

Page 2 of 59 2010-2225 Rev - B
Nidek Medical is a trademark of Nidek Medical Products, Inc.
Mark5 Nuvo® and M5C5 are registered trademarks of Nidek Medical Products, Inc.

2010-2225 Rev - B Page 3 of 59
Table of Contents
3-5
General Safety
Instructions Production and Use of Oxygen 6
Use and Maintenance of the Device 6
Standards and Regulations 6
Section 1.0
Introduction
1.1
Home Service Provider Responsibility 7
1.2
Important Notice and Symbol Explanations 8
1.3
Functional Specifications 9
Section 2.0
Operational Check and Concentration Test
2.1
2.2
2.3
2.4
Description of Operation
Operation Check
Alarm System
2.3.1 Battery Test
2.3.2 Power Failure Alarm test
Oxygen Concentration Test and Specification
9
10
10
11
11
11
Section 3.
0
Patient Instructions
3.1
3.2 General Instructions Routine Maintenance by the Patient 12 12
3.2.1 Cleaning the Cabinet Air Filter
3.2.2 Checking the Alarm System Battery 12 13
Section 4.0
Home Service Provider Maintenance
4.1
Routine Maintenance 13
4.1.1 Cabinet Air Filter 13
4.1.2 Final Product Filter Replacement 13
4.1.3 Inlet Air Filter Replacement 14
4.1.4 Battery Replacement 14
4.1.5 Wick Replacement 14
4.1.6 Recording Maintenance 15
4.2
Cleaning and Infection Control 15
4.2.1 Preparing for New Patient Use 15
Section 5.0
Service
5.1
Components 16
5.2
Cabinet Removal 16
5.2.1 Removing Cabinet Back 16
5.2.2 Removing Cabinet Front 16
5.2.3 Removing Control Panel 16
5.2.4 Main Structure 16

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5.2.5 Caster Replacement 17
5.3
Compressor 17
5.3.1 Compressor Replacement 18
5.3.2 Capacitor Replacement 19
5.4
Process Control Valve 19
5.5
Sieve Bed Replacement 19
5.5.1 Sieve Bed Removal 20
5.5.2 Sieve Bed Installation 20
5.
6
Cabinet Fan Replacement 20
5.7
Circuit Board Replacement 21
5.7.1 Circuit Board Removal 21
5.7.2 Circuit Board Installation 22
5.8
Product Regulator Check and Setting 22
5.8.1 Product Regulator Cleaning or Rebuilding 22
5.9
Pressure Switch Replacement 23
5.10
Circuit Breaker Replacement 23
5.10.1 Circuit Breaker Removal 23
5.10.2 Circuit Breaker Installation 23
5.11
I/0 (ON/OFF) Power Switch Replacement 23
5.11.1 I/0 (ON/OFF) Power Switch Removal 23
5.11.2 I/0 (ON/OFF) Power Switch Installation 24
5.12
Buzzer Replacement 24
5.13
Hour Meter Replacement 24
5.14
Flow Meter Replacement 24
5.14.1 Flow Meter Removal 24
5.14.2 Flow Meter Installation 24
5.15
Power Cord Replacement 24
Section 6.0
Troubleshooting
6.1
Air Pressure Test (P1) 25
6.1.1 High Air Pressure 25
6.1.2 Low Air Pressure 26
6.2
Product Pressure Test (P2) 26
6.2.1 High Product Pressure 26
6.2.2 Low Product Pressure 27
6.3
General Troubleshooting 27
6.4
Troubleshooting Chart 28-32
6.5
Tool Kit and Pressure Test Gauge 33

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Appendices
Exploded
Drawings A1: Base Assembly A1.1: Base Assembly 34 35
A2: Main Structure Assembly – Front View 36
A3: Main Structure Assembly – Rear View 37
A4: Regulator Assembly 38
A5: Compressor Assembly
A5.1: Compressor Assembly 39 40
A6: Control Panel Assembly; OCSI Unit - Front 41
A7: Control Panel Assembly; OCSI Unit - Rear 42
A6.1: Control Panel Assembly; OCSI Unit - Front 43
A7.1: Control Panel Assembly; OCSI Unit - Rear 44
A8: Control Panel Assembly; Non OCSI Unit -
Front 45
A9: Control Panel Assembly; Non OCSI Unit –
Rear 46
A10: Air Tank Assembly 47
A10.1: Air Tank Assembly 48
A11: Front Cabinet Assembly 49
A11.1: Front Cabinet Assembly 50
A12: Rear Cabinet Assembly 51
A12: Rear Cabinet Assembly 52
A13: Module Assembly 53
Parts Listing
A14: Replacement Parts Listing 54-57
Maintenance
Record A15: Maintenance Log 58-59

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General Safety Instructions
Production and use of oxygen
Oxygen is not a flammable gas, but accelerates the combustion of materials. To
prevent fire risks, the MARK5 NUVOshould be kept away from flames,
incandescent sources or sources of heat (cigarettes) and combustible products
such as oil, grease, solvents, aerosols, etc.
Do not use in an explosive atmosphere.
Prevent oxygen from accumulating on upholstered seats or any other fabric. If the
concentrator operates without being administered to a patient, locate it so that the
flow of gas generated is dissipated into the air.
Locate the equipment in a free space (filter to the rear and below) which is well
ventilated and free of fumes or atmospheric pollution.
Use and Maintenance of the Device
Use the electric cable provided and check that the voltage of the mains socket used
complies with the electrical characteristics of the appliance indicated on the
manufacturers plate on the rear of the appliance.
Do not use an extension cord or multiple sockets which can create sparks and
therefore pose a fire risk.
Use of the MARK5 NUVO must be restricted solely to oxygen therapy on medical
prescription in compliance with the daily rate and duration.
Use in other circumstances may represent a hazard to patient health.
Do not use in a specifically magnetic environment (MRI, etc.).
The MARK5 Nuvohas an audible alarm intended to warn the user of any
problems. The user must determine the maximum distance away from the
Nuvobased on the on the sound levels in the environment, to ensure that the
alarm is always audible.
Standards & Regulations
In compliance with UL60601-1 [EN60601-1] (para 6.82.b):
“The manufacturer, assembler, installer or importer are not considered to be
responsible for consequences or the safety, reliability and characteristics of a
device unless,
● the assembly, extensions, adjustments modifications or repairs have been
performed by persons authorized by the manufacturer,

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● the electrical installation of the corresponding premises complies with appropriate
regulations and codes,
● the device is used in accordance with the instructions for its use.
If the replacement parts used for periodic servicing by an approved technician do
not comply with the manufacturer’s specifications, the manufacturer is absolved of
all liability in the event of an incident.
Do not open the equipment when it is powered on: risk of electrocution.
This device complies with the requirements of the FDA Quality System Regulation
and EU Directive 93/42/EEC, but its operation may be affected by the use in the
surrounding area of appliances such as diathermy, high frequency electro-surgical
instruments, defibrillators, short wave treatment appliances, cell-phones, CB
devices and other portables, microwave ovens, induction hot plates or remote
control toys, and more generally, by electromagnetic interference exceeding the
levels specified in standard IEC(EN) 60601-1-2.
1.0 Introduction
1.1 Home Service Provider Responsibility
All Home Service Providers of the Nidek Medical Mark5 Nuvo® Oxygen
Concentrator must assume responsibilities for handling, operational check-out,
patient instruction, and maintenance. These responsibilities are outlined below and
throughout this manual.
WARNING
Mark5 Nuvo units must not be used for or with any life-supporting or life sustaining
applications. Patients unable to communicate discomfort while using this device
may require additional monitoring. Advise patients to immediately notify their Home
Service Provider(s) and/or physician(s) in case of an alarm or any discomfort.
As a Home Service Provider, you must do all of the following:
● Inspect the condition of each Mark5 Nuvo® unit immediately upon
delivery to your business location. Note any sign of damage, external or
internal, on the delivery receipt, and report it directly to both the freight
company and Nidek Medical Products, Inc. immediately.
● Check the operation of each Mark5 Nuvo® before delivery to a patient.
Always operate the unit for a reasonable length of time and check that the
oxygen concentration level is within specifications as referred to in
Section 2.4. Test the battery and power disconnect alarm as described in
Section 2.3 of this manual.

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● Deliver Mark5 Nuvo® units only to patients authorized by a physician’s
prescription. The Mark5 Nuvo® must not be used as a life-supporting or
life sustaining device. A backup supply of oxygen must be available.
● Instruct patients how to use the Mark5 Nuvo® in conjunction with the
Patient Manual.
● Instruct patients to notify their physicians and/or Home Service Providers
if they experience any signs of discomfort.
● Instruct each patient how to perform routine maintenance of the cabinet
air filter and how to check the alarm system battery. (Refer to Section
3.2.)
Be available to service each patient at any time. Maintain the Mark5
Nuvo® in accordance with Section 4.0.
Repair components and replace parts only as outlined in this manual. Use only
Nidek Medical parts for replacement in Mark5 Nuvo® Oxygen Concentrators.
● Refer to the Mark5 Nuvo® Product Warranty if parts replacement is
required within the warranty period.
1.2 Important Notice and Symbol Explanations
As you read the manual, pay special attention to the WARNING, CAUTION, and
NOTE messages. They identify safety guidelines or other important information as
follows:
WARNING: Describes a
hazard or unsafe practice that can result
in severe bodily injury or death.
CAUTION:
Describes a hazard or unsafe practice that can result
in minor bodily injury or property damage.
NOTE:
Provides information important enough to emphasize
or repeat.
The following harmonized symbols (pictograms), used for non-English language
countries, will be located on the exterior of the Mark5 Nuvo® unit:
Read the accompanying documents; particularly the patient
operating guide.
Store, ship and use the device in an upright condition.
No smoking within five feet of this device, oxygen-carrying tubing, or
accessories.
Indicates an alarm signal.

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Do not use any oil or grease on or near the device
1.3 Functional Specifications
Dimensions: 15.5 in. long, 15.6 in. wide, 27.8 in. tall
(394 mm long, 396 mm wide, 706 mm high)
Weight: 50 to 54 Ib (22.5 to 24.5 kg) depending on sound attenuation;
Electrical 120 VAC, 60 Hz, 4 amps, 410 watts
Requirements: 220 VAC, 50 Hz, 2 amps, 420 watts
Capacity: 5 liters per minute at 90% oxygen
(Based on 70°F [21°C] at sea level)
Accuracy: Flow meter ±5% full scale. (Based on pre-calibrated analysis.)
Concentration: 1 - 3 liters per minute at 95% + 0.5 / - 3%
4 liters per minute at 92% + 3.5 / - 3%
5 liters per minute at 90% + 5.5 / - 3%
Response Time: Acceptable concentration is normally achieved in about
90 seconds; allow 5 minutes to attain full concentration.
Positioning: Operate the unit in an upright position, maintaining at
least six inches of open space on all sides for ventilation.
2.0 Operational Check and Concentration Test
2.1 Description of Operation
Air enters the Mark5 Nuvo® Oxygen Concentrator through an external cooling air
intake filter. This filtered air enters the compressor via a suction resonator and fine
filter, which quiets the suction sounds made by the compressor. Pressurized air
then exits the compressor and passes through a heat exchanger into an air tank.
The heat exchanger reduces the temperature of the compressed air and the air tank
stores air when feed is interrupted. Next, a rotary poppet feed valve directs the air
into one of two sieve beds that contain molecular sieve. The special characteristic
property of molecular sieve is that it physically attracts (adsorbs) nitrogen when air
passes through this material, thus enabling the production of high purity oxygen.
There are two sieve beds or adsorbent columns; while one produces high purity
oxygen, the other is purged of the nitrogen it adsorbed (collected) while it was
producing oxygen. Each column produces oxygen for approximately four seconds
and delivers it to the product storage volume in the end of the column. Oxygen exits
the adsorbent column through a pressure regulator, flow control valve, flow meter,
and final product filter. The flow control valve, which is part of the flow meter,
controls the flow rate of oxygen delivered to the patient. The Mark5 Nuvo® unit

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delivers up to 95% oxygen concentration at flow rates from 1 to 5 l/min. The
remaining constituents of the product gas stream are nitrogen and argon, both of
which are part of the air we breathe, are inert and are completely safe.
2.2 Operational Check
Nidek Medical runs each device through a burn in period and tests every Mark5
Nuvo® Oxygen Concentrator thoroughly after manufacture before releasing for
shipment. As the home service provider, it is your responsibility to perform the
following test to ensure that no damage occurred in shipping or handling.
1. Open and inspect all concentrator cartons upon receipt. Unpack each
unit and remove it from its carton. Inspect the unit itself for damage. If
the exterior of the carton is damaged, or the unit itself is damaged,
note it on the freight bill signed by the driver.
● Before plugging the unit into the wall outlet, actuate the I/0
(ON/OFF) switch to the I (ON) position and note that the audible
alarm sounds continuously. (See Section 2.3). Move the switch to
the 0 (OFF) position.
2. Plug in the power cord of the unit, and set the I/0 (ON/OFF) switch to
the I (ON) position. Check to see that the following occurs:
● The compressor runs, listen for the sound.
● Exhaust air flows out of the bottom of the unit.
● OPTIONAL for Units Equipped with Oxygen Concentration Status
Indicator (OCSI): The OCSI green light remains off until the oxygen
concentration reaches 85% ± 3% (82% ± 2% for 50 Hz units)
(approximately two minutes).
3. Turn the flow meter adjustment knob counterclockwise until it stops
(wide open). The flow meter should register in excess of 5.5 liters/min.
If not, refer to Section 5.8 to adjust the product regulator.
4 Perform an oxygen concentration test, as described in Section 2.4.
2.3 Alarm System
The Mark5 Nuvo® Oxygen Concentrator is equipped with a battery-powered alarm
system, which sounds a continuous and loud alarm when a power failure occurs or
when one or more cycle variables are not within specification. It sounds an alarm if
the high or low pressure indicators are activated or if the optional OCSI detects
lower than predetermined levels of oxygen concentration. The alarm remains on
until you correct the alarm condition or you set the I/0 (ON/OFF) switch to the 0
(OFF) position. Refer to Section 6.0 for a list of probable alarm causes,

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2.3.1 Battery Test
The Mark5 Nuvo® battery can be checked by observing that the continuous alarm
sounds when the I/0 (ON/OFF) switch is moved to the I (ON) position when the unit
is unplugged from the wall outlet.
2.3.2 Power Failure Alarm Test
To test the power failure alarm, perform the following actions:
Unplug the power cord from the wall outlet, and set the I/0 (ON/OFF) switch to the I
(ON) position.
This should immediately activate the audible alarm. If it does not, refer to the
troubleshooting chart in Section 6.0 of this manual.
2.4 Oxygen Concentration Test and Specification
To ensure that the output of oxygen from the device is within specification, you must
perform an oxygen concentration test. Test the unit upon delivery to a patient and at
periodic intervals. Home Service Providers, based on their expertise and
documentation, may establish and implement their own plans for checking oxygen
concentration. The interval established may be longer or shorter than 90 days,
which is Nidek Medical’s default time period for providers who do not choose to
establish their own plan.
1. If an oxygen humidifier bottle is used, remove it from the oxygen outlet.
2. Connect a calibrated oxygen concentration analyzer to the oxygen outlet.
3. Set the I/0 (ON/OFF) power switch to the I (ON) position. (It takes
approximately five minutes for the oxygen concentration to stabilize.) Take oxygen
concentration readings over a period of several minutes to reduce any cyclic
variations
4. Verify that the product flow rate delivered by the unit matches the patient’s
prescription and does not exceed the capacity of the unit.
5. Disconnect the oxygen analyzer, and reconnect the humidifier bottle (if used)
and any other equipment / accessories that may be required.
6. Adjust the flow meter adjustment knob to the prescribed flow rate.
NOTE
Do not measure oxygen concentration output after the product stream passes
through a humidifier bottle, erroneous readings will result and your oxygen
concentration measuring device might be damaged.

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Nidek Medical Mark5 Nuvo® Concentration Specifications
Liter Flow Specification Within Specification
1 to 3 l/min 95% + 0.5 / - 3% 92% or higher
4 l/min 92% + 3.5 / - 3% 89% or higher
5 l/min 90% + 5.5 / - 3% 87% or higher
3.0 Patient Instructions
3.1 General Instructions
It is important that patients thoroughly understand how to operate the Nidek Medical
Mark5 Nuvo® unit. This enables proper treatment as prescribed by a qualified,
licensed physician. You must explain that the purpose of this therapy is to alleviate
symptoms. If patients experience any discomfort or the unit alarms, they must notify
their Home Service Provider and/or physician immediately. You, as the Home
Service Provider, are responsible to see that each patient receives the Patient
Manual. Explain each step in the operation of the unit to the patient in reference to
this manual.
3.2 Routine Maintenance by the Patient
To ensure accurate output and efficient operation of the unit, the patient must
perform two simple routine maintenance tasks:
• Clean the cabinet air filter
• Check the alarm system battery
3.2.1 Cleaning the Cabinet Air Filter
NOTE: The patient must clean this filter weekly, as described below. The filter
may require daily cleaning if the Mark5 Nuvo® unit operates in a harsh
environment such as a house heated by wood, kerosene, or oil, or one
with excessive cigarette smoke.
1 Remove the dirty cabinet
air filter from the back of the
Mark5 Nuvo® unit.
2 Wash the dirty filter in warm water
with household
detergent, and rinse.
3 Use a soft absorbent towel to remove excess water.
4
Reinstall the clean air filter on the grille in the back of
the unit.

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3.2.2 Checking the Alarm System Battery
See Procedure described in Paragraph 2.3.1
4.0 Home Service Provider Maintenance
4.1 Routine Maintenance
The Mark5 Nuvo® unit has two filters and a 9-volt battery that require scheduled
maintenance and replacement.
To ensure that the output of oxygen from the unit is within specification, you must
perform an oxygen concentration test. Test the unit upon delivery to a patient and at
periodic intervals. Home Service Providers, based on their expertise and
documentation, may establish and implement their own practices for checking
oxygen concentration. Consult Nidek Medical’s Service and Maintenance Log (A-
15) for the recommended intervals for testing.
Nidek Medical does not require preventive maintenance on the concentrator. You
do not need to perform any maintenance as long as the Mark5 Nuvo® unit remains
within specifications at the prescribed flow rate. (Refer to Section 2.4)
Cabinet Air Filter
The external cabinet air filter is located on the back of the unit, You can easily
remove it by hand. Instruct the patient to clean this filter weekly. (Refer to Section
3.2.1.)
NOTE
The filter may require more frequent cleaning if the Mark5 Nuvo® unit operates in a
harsh environment such as a house heated by wood, kerosene, or oil, or one with
excessive cooking, cigarette smoke or atmospheric dust.
4.1.2 Final Product Filter Replacement
The final product filter does not require periodic replacement; it needs to be
replaced only if it restricts oxygen flow. It is suggested that it be replaced whenever
the sieve module is repaired or replaced and after the compressor is rebuilt.
1. Set the I/0 (ON/OFF) switch to the 0 (OFF) position, and unplug the power
cord.
2. Remove the cabinet back to locate the final product filter.
NOTE: Observe the position of the filter before removal.
3. Separate the silicone tubing from both sides of the filter.
4. Install the new filter with the inlet side in the same position as before. Push
the tubing together so that it overlaps the barbs of the final product filter

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connections.
5. Record information about the final product filter replacement in Appendix 15
of this manual and online at www.nidekmedical.com under the ‘Maintenance
Log’ tab.
6. Reinstall the cabinet back.
4.1.3 Inlet Air Filter Replacement
The inlet air filter requires inspection at each patient visit. The filter should be
replaced annually, or more often depending on environment.
1. Set the unit I/0 (ON/OFF) switch to the 0 (OFF) position, and unplug the
power cord.
2. Remove the rear cabinet access panel to locate the inlet air filter.
3. Remove filter from the unit, and replace with a new filter.
4. Record information about the filter replacement in Appendix 15 of this
manual and online at www.nidekmedical.com under the ‘Maintenance Log’
tab.
5. Reinstall the access panel.
4.1.4 Battery Replacement
Each time the standard Mark5 Nuvo® unit is turned on, the alarm must sound loudly
for approximately five seconds to indicate a good battery. An alarm that does
anything other than sound loudly for five seconds indicates a weak battery and
requires replacement. For units with OCSI, actuate the switch with the power cord
unplugged to test the battery.
To replace the battery, take the following steps:
1. Set the I/0 (ON/OFF) switch to the 0 (OFF) position, and unplug the power
cord.
2. Remove the access panel in the cabinet back.
3. Pull the battery from the mounting slot and remove the connection wires.
4. Attach the new battery to the connector and reinsert it into the mounting slot.
5. Set the I/0 (ON/OFF) switch to the I (ON) position to test the alarm.
6. Record the battery replacement information in Appendix 15 of this manual
and online at www.nidekmedical.com under the ‘Maintenance Log’ tab.
7. Reinstall the access panel.
4.1.5 Wick Replacement
The wick is installed in the process air stream of the unit, connected to the air tank,
to assist with removal of moisture from the air. This helps prevent premature
contamination of the sieve beds, particularly in humid climates. The wick should be
replaced at each compressor service / module replacement; it is suggested that
more frequent replacement be done in very humid climates. The wick is located in
a bushing located just to the right of the gearmotor. It is installed in a quick release
fitting. Pull the fitting from the bushing by hand – it may require several pounds of
force, remove the wick and install a new one in its place. Re-insert the wick end
and fitting into the bushing so the wick is totally below the base plate surface.

2010-2225 Rev - B Page 15 of 59
4.1.6 Recording Maintenance
As the Home Service Provider, it is suggested that you record all routine
maintenance and repairs performed on the Mark5 Nuvo® unit, including hours and
dates of service in Appendix 15 of this manual and online at www.nidekmedical.com
under the ‘Maintenance Log’ tab.
4.2 Cleaning and Infection Control
With the growing concern about possible cross infection from home oxygen
equipment (i.e.. oxygen concentrators) from one home care patient to another,
appropriate cautions should be exercised.
The organisms of most concern are M. Tuberculosis, HIV, and Viral Hepatitis.
These are potentially pathogenic.
Tuberculosis can survive outside of the human body, but its mode of transmission is
by droplet nuclei. When infected individuals cough, they release droplet nuclei into
the air, and these carry the Tuberculosis organism. Another person may breathe in
these droplet nuclei, but prolonged exposure to the infected person is usually
necessary for infection to occur.
HIV and Viral Hepatitis are both viruses, which are not living cells themselves but
which can duplicate when in a living “host” cell. Both of these organisms are usually
passed on by person-to-person contact, and both need to be in the human body to
survive. Once outside the body, viruses can survive for only a short period of time.
4.2.1 Preparing for New Patient Use
When you remove the Mark5 Nuvo® from a patient’s home, always dispose of the
used nasal cannula and humidifier bottle. Clean the exterior of the Mark5 Nuvo®
with a soapy water solution or commercial detergent cleaner to remove any gross
debris, organic or otherwise. Be careful not to get any liquid into the interior of the
unit.
Next, clean the exterior with either a common chemical disinfectant or a bleach
solution* and allow it to air dry. For the bleach solution, wear eye and skin
protection to prevent exposure to the chlorine. Retest the Mark5 Nuvo® before you
return it to your inventory.
Replace the cabinet air filter between each patient’s use or clean with warm soapy
water if it is in good condition. Clean this filter at least once per week or more
frequently if operated in a dusty environment.
*Make the bleach solution a 1:100 dilution of 5.25% sodium hypochlorite. Mix one
part household bleach (e.g. Clorox) with 99 parts cold tap water. To measure the

Page 16 of 59 2010-2225 Rev - B
solution easily, take 1/4 cup of household bleach, and mix it with a gallon of cold tap
water. Allow the mixture to sit on potentially contaminated surfaces for 10 minutes.
5.0 Service
5.1 Components
The design of the Nidek Medical Mark5 Nuvo® Oxygen Concentrator allows for
easy access and removal of most components. This allows you to perform
scheduled maintenance, repair, and replacement of parts with minimal time and
effort. The inlet air filter and battery are conveniently located inside the small
access panel in the cabinet back.
CAUTION:
For your safety, be sure to set the I/0 (ON/OFF) switch to the 0 (OFF)
position and unplug the power cord before you service the Mark5 Nuvo®
Oxygen Concentrator.
NOTE: Record all scheduled maintenance. (Refer to Section 4.1.6.)
5.2 Cabinet Removal
5.2.1 Removing Cabinet Back
To remove the cabinet back, remove two screws near the base (one on each side)
and two inset screws at the top just under the handle.
5.2.2 Removing Cabinet Front
To remove the cabinet front, remove two screws near the base (one on each side)
adjacent to the rear cabinet screws and two inset screws at the top just under the
handle. It is necessary to remove the cabinet back to access the top screws.
5.2.3 Removing Control Panel
Eight screws hold the control panel in place; the front cover must be removed to
access these screws. It is necessary to remove the electrical wiring and pneumatic
tubing to fully release the control panel.
5.2.4 Main Structure
The weight and forces of the internal components rest solely on four parts: the main
structure, the compressor plate, the base-plate and the base. These parts were
specially designed and formed. They should never require replacement under
normal use.

2010-2225 Rev - B Page 17 of 59
5.2.5 Caster Replacement
The casters are a push in type that does not require any fastener. Lay the device
on its back to access the casters from the bottom. Pull them straight out away from
the bottom.
5.3 Compressor
The compressor is the pump within the oxygen concentrator that supplies air to the
separation process performed by the sieve beds. The pressure generated by the
compressor forces oxygen to flow out of the top of the sieve columns.
The compressor is the likely cause of two potential specific problems:
a. An insufficient amount of air is supplied to the process, and
b. An excessive sound level.
● Air Supply
Compressor output refers to how much compressed air the compressor can
produce. This depends upon the model of the compressor, length of stroke, piston
diameter, speed of rotation and condition of seals. The cup seals form the seal
between the piston and the cylinder wall. As the cup seals wear, the output begins
to gradually decrease. This reduction in compressor output results in less air, and
thus less oxygen, entering the sieve beds. Therefore, the production of oxygen
decreases.
Because this drop in oxygen production occurs over a long period of time,
preventive maintenance on the compressor is not required.
You can continue a patient’s therapy on the Mark5 Nuvo® unit as long as the
oxygen concentration level at the prescribed liter flow rate is within Nidek Medical’s
specification limits. Refer to Section 2.4.

Page 18 of 59 2010-2225 Rev - B
Compressor
Pressure
Flow
Air
Filter
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
1 bar
Pressure
Gauge
Air Flow
Meter
0 to 100 l/min
Restrictor
● Sound Level
The sound level is largely determined by the condition of the compressor’s
bearings.
There are four bearings located within the compressor that allow the inner
components of the compressor to rotate. If the bearings wear to the point that they
become loose and noisy, the compressor becomes noticeably loud and needs
servicing. The life of a compressor is determined primarily by its operating
temperature. It is extremely important that the cabinet air filters are cleaned and
replaced as required.
5.3.1 Compressor Replacement
Remove Compressor Assembly
To remove the compressor assembly for exchange, follow the steps listed below:
1. Set the unit’s I/0 (ON/OFF) switch to the 0 (OFF) position, and unplug the
power cord.
2. Remove the cabinet back and front.
3. Disconnect the suction tube.
4. Disconnect the two compressor power cable leads and the two leads to the
capacitor at the inline connector.
5. Remove the three screws that connect the compressor plate to the base of
the unit, lift and slide out the compressor assembly.
6. Remove compressor from the plate by removing the four compressor bolts.
7. Remove tie wrap from compressor plate wiring harness.
8. Remove the heat exchanger tubing and fittings.

2010-2225 Rev - B Page 19 of 59
Compressor Assembly Installation
To install the rebuilt compressor assembly, follow the steps listed below:
1. Perform the compressor removal procedure in reverse order.
2. Leak test all connections.
5.3.2 Capacitor Replacement
The capacitor helps the compressor to start and run more efficiently. If the
compressor cannot start, the capacitor may be defective and require replacement.
The capacitor should be replaced at each compressor service / module
replacement. To replace the capacitor, take the following steps:
1. Set the unit’s I/0 (ON/OFF) switch to the 0 (OFF) position, and unplug
the power cord.
2. Remove the rear and front cabinets.
3. Disconnect the two leads to the capacitor and remove the nut from the
mounting screw.
4. Remove the nut and washer below the capacitor.
5. To install the new capacitor, connect the leads and replace the capacitor and
associated hardware.
5.4 Process Control Valve
The Mark5 Nuvo® uses a gearmotor powered rotary cam-operated poppet valve
assembly to control the air separation process. There is a feed port that connects
to the air tank and an exhaust port that connects to the exhaust muffler. There are
three possible valve states as follows:
1. Air feed connected to sieve bed A and exhaust connected to sieve bed B.
2. Air feed connected to sieve bed B and exhaust connected to sieve bed A.
3. Both ports closed; this is a very short time period during which air pressure
builds in the air tank.
The control valve of the Mark5 Nuvo® unit requires no scheduled maintenance. If a
valve does not function as required, it is best to replace the complete sieve module
as it is probable that one or both of the beds has been damaged.
5.5 Sieve Bed Replacement
CAUTION:
Do not expose molecular sieve (contents of bed) to air for an extended period of
time. Prolonged exposure of molecular sieve to the moisture in room air results in
contamination and permanent damage to the sieve material. Keep all openings to
the sieve beds sealed during periods of storage.

Page 20 of 59 2010-2225 Rev - B
NOTE
If replacement is necessary, you must replace both sieve beds at the same time. It
is recommended to replace the sieve beds and control valve module as a complete
assembly.
5.5.1 Sieve Bed Removal
1. Set the unit’s I/0 (ON/OFF) switch to the 0 (OFF) position and unplug the
power cord.
2. Remove the cabinet back.
3. Disconnect the 1/4-inch product tube from the top of one of the beds.
4. Remove the 4 tie-wraps ( 2 from each sieve bed ). Note their position and
orientation.
5. Remove two “Z” brackets; one from the top of each of the sieve beds.
6. Lift the module up and out of the base plate cradle.
7. Unplug the valve gearmotor electrical leads at the in-line connections.
8. Manipulate the module so that the black exhaust hose can be removed from
the fitting on the valve.
9. Loosen the hose clamp and remove the black feed hose from the fitting on
the valve.
5.5.2 Sieve Bed Installation
To install the sieve beds, follow the sieve bed removal procedure in reverse order. It
is very important to tighten all tubes to eliminate leaks. However, do not over
tighten.
To check for leaks, take the following steps:
1. Plug in the unit.
2. Set the unit’s I/0 (ON/OFF) switch to I (ON) for three minutes with the
flowmeter closed to pressurize the system.
3. Apply soapy water around the hose connections at the valve and the
air tank; check for leaks.
Caution: There is an electrical shock hazard with the Power ON. Be
careful that no water contacts any of the electrical connections.
NOTE
Even small leaks can affect concentrator performance and can cause contamination
of the sieve. Careful leak testing is important.
5.6 Cabinet Fan Replacement
The cabinet fan for the Mark5 Nuvo® is located under the compressor. Refer to the
troubleshooting chart in Section 6.0 of this manual for instances where replacement
of the fan may be required.
To replace the cabinet fan in the Mark5 Nuvo® unit, take the following steps:
1. Set the unit’s I/0 (ON/OFF) switch to the 0 (OFF) position and unplug the