DeVilbiss 525DS User manual

For Product
Numbers:
525DS
525KS
SERVICE MANUAL
DANGER – NO SMOKING
CAUTION-Federal (U.S.A.) law restricts this device
to sale by or on the order of a physician.
DeVi l b i s s ®5-li t e r Co m p a C t ox y g e n Co n C e n t r a t o r

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TABLE OF CONTENTS
GENERAL INFORMATION
Introduction...................................................................................................................................................................................... 3
Important Safeguards ....................................................................................................................................................................... 3
Safety Precautions and General Warnings........................................................................................................................................ 3
UNPACKING AND SETUP
Initial Inspection................................................................................................................................................................................ 4
Patient Setup .................................................................................................................................................................................... 4
Operating Instructions...................................................................................................................................................................... 5
MAINTENANCE
Patient Alert System......................................................................................................................................................................... 6
Routine Patient Maintenance............................................................................................................................................................ 6
Periodic Homecare Provider Preventative Maintenance ................................................................................................................. 7
Between Patient Maintenance.......................................................................................................................................................... 7
Preventative Maintenance Summary................................................................................................................................................ 7
TROUBLESHOOTING
System Operation ............................................................................................................................................................................ 8
Normal Operating Sequence ........................................................................................................................................................... 8
Simplified Troubleshooting ............................................................................................................................................................... 9
Troubleshooting Chart A.................................................................................................................................................................. 10
Troubleshooting Chart B .................................................................................................................................................................. 11
Troubleshooting Chart C.................................................................................................................................................................. 11
Troubleshooting Chart D ................................................................................................................................................................. 11
Troubleshooting Chart E .................................................................................................................................................................. 12
Troubleshooting Chart F .................................................................................................................................................................. 12
COMPONENT TESTING, REPAIR, AND REPLACEMENT
Proper Repair Procedures................................................................................................................................................................ 13
Cabinet Removal .............................................................................................................................................................................. 14
Accumulator Pressure Test .............................................................................................................................................................. 14
Capacitor.......................................................................................................................................................................................... 14
Compressor ..................................................................................................................................................................................... 15
Cooling Fan ...................................................................................................................................................................................... 16
Final Check Valve ............................................................................................................................................................................. 16
Flow Meter....................................................................................................................................................................................... 16
Hour Meter ...................................................................................................................................................................................... 16
Molecular Sieve Beds ....................................................................................................................................................................... 17
Power Cord...................................................................................................................................................................................... 17
Power Switch ................................................................................................................................................................................... 17
Pressure Regulator ........................................................................................................................................................................... 17
Printed Circuit Board (PC Board).................................................................................................................................................... 18
Rotary Valve...................................................................................................................................................................................... 18
Sieve Bed Check Valves ................................................................................................................................................................... 18
FIGURES, DIAGRAMS, AND VIEWS
Figure Index...................................................................................................................................................................................... 19
Exterior Views.................................................................................................................................................................................. 20
Interior Views................................................................................................................................................................................... 23
Other Figures ................................................................................................................................................................................... 34
Pneumatic and Wiring Diagrams...................................................................................................................................................... 37
WARRANTY INFORMATION .................................................................................................................................................... 39
ORDERING INFORMATION AND PARTS LIST
Ordering Information....................................................................................................................................................................... 40
Parts Return and Ordering Policy..................................................................................................................................................... 40
Parts List........................................................................................................................................................................................... 41
SPECIFICATIONS......................................................................................................................................................................... 43

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GENERAL INFORMATION
INTRODUCTION
This service manual was designed to provide DeVilbiss Healthcare qualified service technicians and homecare providers with the proper maintenance,
service, safety, and repair procedures for the DeVilbiss Oxygen Concentrator.
Read and understand all the information contained in this service manual before attempting to operate or perform any maintenance on the
concentrator.
An oxygen concentrator is a device that delivers highly concentrated oxygen for therapeutic applications.
Room air is a mixture of 78% nitrogen, 21% oxygen, 1% argon and other gases. The concentrator draws in room air, separates the nitrogen from the
oxygen, and delivers concentrated oxygen to the patient through an oxygen port.
For more in-depth classroom type training, DeVilbiss holds oxygen concentrator service schools. For service school information, contact the
Respiratory Technical Service Department at 1-800-338-1988 (814-443-4881).
NOTE–DeVilbiss reserves the right to alter or change the design of the DeVilbiss Oxygen Concentrator series. Hence, slight differences in
construction or components may exist between the unit in hand and what is described in this manual.
IMPORTANT SAFEGUARDS
Read all instructions before operating the oxygen concentrator. Important information is highlighted by these terms:
WARNING: Safety information for hazards that might cause serious injury or death.
CAUTION–Information for preventing damage to the product.
NOTE–Information to which you should pay special attention.
SAFETY PRECAUTIONS AND GENERAL WARNINGS
A. CAUTION–Federal (U.S.A.) law restricts this device to sale by or on the order of a physician.
B. WARNING: Oxygen promotes rapid burning. Do not smoke when using this unit or when near a person receiving
oxygen therapy. Do not operate the oxygen concentrator within a minimum of five feet (1.6m) from hot, sparking,
or burning objects or naked flames. Do not use in rooms heated by paraffin or portable gas heaters.
C. Do not place a humidifier with an oxygen patient unless prescribed by a physician and then only a bubble-type humidifier should
be used.
D. Do not connect the oxygen concentrator to an electrical outlet controlled by a wall switch; the outlet should be independent of
other appliances.
E. Do not use an electrical adapter or extension cord with the oxygen concentrator.
F. Only operate the oxygen concentrator with all filters in place; do not operate if the air filter is wet.
G. WARNING: Electric shock hazard. Do not remove cabinet. The cabinet should only be removed by a qualified
DeVilbiss homecare provider.
H. WARNING: Disconnect the power cord from the wall outlet before attempting repairs on the unit. Extra care
should be taken if it is necessary to operate the unit with the cabinet removed.
I. WARNING: Do not use oils, greases, or any petroleum-based solvents/cleaners on or near the unit. Use only
materials that are compatible with oxygen.
J. WARNING: Electric Shock Hazard. When replacing the capacitor, do not touch the terminals or allow metal
objects to come in contact with the terminals on the capacitor. The capacitor may hold a charge for several days
after the unit is turned off. The capacitor is located in the base of the unit next to the cooling fan.
K. Use only DeVilbiss concentrator replacement parts and accessories.
L. Do not use regenerated sieve material.
DANGER
NO SMOKING

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UNPACKING AND SETUP
INITIAL INSPECTION
It is suggested that an initial inspection be performed upon receiving the oxygen concentrator.
1. After removing the DeVilbiss Oxygen Concentrator from the carton, examine it for any external damage. If shipping damage has occurred,
contact the DeVilbiss Customer Service Department at 1-800-338-1988 (814-443-4881) for specific instructions. Save the carton for possible later
return; note the position of the unit and placement of the packing material.
2. Open the filter door and record the number of hours on the hour meter. Check to make sure the air filter is in place.
3. Check to be sure the intake bacteria filter is in place.
4. Plug the unit into an electrical outlet, turn the unit “On,” and check the audible and visible alerts.
5. Set the flow meter to maximum recommended liter flow and let the unit run for at least 20 minutes.
6. Use an oxygen analyzer to check the concentration.
NOTE–Iftheunitfailstooperateproperly(oxygenconcentrationnotwithinspecication)orifinternaldamageisfound,contacttheDeVilbiss
CustomerServiceDepartmentat1-800-338-1988(814-443-4881).
PATIENT SETUP
1. Position the unit near an electrical outlet in the room where the patient spends most of his or her time.
NOTE–Do not connect to an electrical outlet controlled by a wall switch. The outlet should be independent of other appliances.
2. Position the unit at least 6 inches (16 cm) from walls, draperies, or any other objects that might prevent the proper flow of air in and out of the
oxygen concentrator.
3. Locate the unit a minimum of 5 feet (1.6 meters) from fireplaces, radiators, heaters, and hot-air registers.
Oxygen promotes rapid burning. Do not smoke when using this unit or when near a person receiving oxygen therapy. Do
not operate the oxygen concentrator within a minimum of 5 feet (1.6 meters) from hot, sparking, or burning objects or
naked flames. Do not use in rooms heated by paraffin or portable gas heaters.
Electric Shock Hazard. Only qualified DeVilbiss Healthcare homecare providers may remove the cabinet.
4. Attach the appropriate oxygen accessories (oxygen tubing or humidifier) to the oxygen outlet port.
NOTE–Amaximumof50feet(15meters)oftubingplus7feet(2.1meters)ofcannulaplusabubblehumidierisallowedbetweenthe
concentrator and the patient.
Oxygen Tubing Only Connection
1. Thread the cannula fitting (part #CN100) onto the oxygen outlet port.
2. Attach the 5/32” (4 mm) I.D. oxygen tubing (part #OST07, OST15, OST25, or OST50).
Oxygen Tubing with Humidification Connection
If the physician has prescribed an oxygen humidifier as part of the patient’s therapy, follow these steps:
1. Fill the humidifier bottle (part #HUM16) with distilled, demineralized, or boiled water. Do not overfill. (If using a prefill, go to Step 3.)
2. Thread the wing nut located on the top of the humidifier bottle to the oxygen outlet port so that it is suspended. Make sure it is securely
tightened.
3. Attach the 5/32" (4 mm) I.D. oxygen tubing (part # OST07, OST15, OST25, or OST50), not to exceed 50 feet (15 meters), directly to the
humidifier bottle outlet fitting.
NOTE–Foroptimumperformance,theDeVilbissOxygenConcentratorhasapresetnominaloutputpressureof8.5psi(58.6kPa).Use
only“bubble-type”humidiers.Donotuse“jet-type”humidiers.
NOTE–Condensationfromthehumidiermayoccurinlongerlengthsoftubingorifthetubingislayingonacoldoor.
When ready for operation
1. Attach the nasal cannula, catheter, or face mask to the oxygen tubing (per the manufacturer’s directions).
2. Follow the Operating Instructions on the next page.
WARNING

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UNPACKING AND SETUP
OPERATING INSTRUCTIONS
1. Remove the power cord completely from the strap. Make sure the power switch is in the “Off” position.
2. 115 Volt Units– Insert the plug into an electrical outlet. The DeVilbiss Oxygen Concentrator uses a two-prong polarized plug and is double-
insulated to protect against electric shock.
220/240 Volt Units – Ensure it is connected to the unit before inserting plug into an appropriate electrical outlet.
The plug on the DeVilbiss 525DS concentrators has one blade wider than the other. To reduce the risk of electric shock,
this plug is intended to fit in a wall outlet only one way. Do not attempt to defeat this safety feature.
Improper use of the power cord and plugs can cause a burn, fire, or other electric shock hazards. Do not use the unit if
the power cord is damaged.
Oxygen promotes rapid burning. Do not smoke when using this unit or when near a person receiving oxygen therapy. Do
not operate the oxygen concentrator within a minimum of five feet (1.6m) from hot, sparking, or burning objects or naked
flames. Do not use in rooms heated by paraffin or portable gas heaters.
3. Press the power switch to the “On” position. When the unit is turned “On,” all four indicator lights (Power, Service Required, Low Oxygen, and
Normal Oxygen) on the front panel will briefly illuminate and an audible signal will sound (the patient alert system) momentarily. After a few
seconds, only the “Power” and “Normal Oxygen” lights will remain on.
4. Slowly turn the flow meter knob until the flow meter ball is centered on the line next to the appropriate flow rate.
NOTE–Whentheowmeterknobisturnedclockwise,theowdecreases(andeventuallywillshutofftheoxygenow).Whentheknob
isturnedcounter-clockwise,theowincreases.
NOTE–Uselowoutputowmeter(part#515LF-607)forowratesunder1lpm.
NOTE–Theunitmayrequireupto20minutesfortheoxygenconcentrationandowratetostabilize.Theowrateshouldbemonitored
andreadjustedifnecessary.
5. The flow meter has a locking device. If it is necessary to preset and lock in the prescribed flow rate, tighten the set screw located on the hex nut
just below the control knob using a 1/16" Allen bit. No adjustment can be made without loosening the set screw.
6. The DeVilbiss oxygen concentrator is now ready for use.
PATIENT ALERT SYSTEM
The DeVilbiss Oxygen Concentrator patient alert system will detect unit component failure. This system is comprised of both visible and audible alerts
which signal the patient if a malfunction should occur.
DeVilbiss OSD®Operation
The OSD is a device within DeVilbiss concentrators that monitors the oxygen produced by the unit. The OSD operates as follows:
• NormalOxygen(greenlight)-oxygenpuritynormal
• LowOxygen(yellowlight)-oxygenpuritylow–requiresservicing
NOTE–If the oxygen purity continues to fall, an audible signal will sound intermittently. If the oxygen purity continues to fall to a low enough level,
theyellow“LowOxygen”lightwillturnoffandthered“ServiceRequired”lightwillturnon.
NOTE–RefertoSpecicationsforspecicalertsettings.
NOTE–AfterPowerOn,theOSDconductsacontinuousdiagnosticevaluationtocheckforafaultinthepiezoelectronics.Ifthisconditionis
detected by the OSD electronics at any time during concentrator operation, the green “Normal Oxygen” OSD light will turn off and the
beepingaudiblealertandblinkingred“ServiceRequired”lightactivate.Otherwisefortherstfteenminutesofoperation,thegreen
“NormalOxygen”lightwillremainilluminatedduringtheoxygenstabilizationprocess.Afterthattime,theOSDwillbeginmonitoringthe
oxygen purity every second.
WARNING

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MAINTENANCE
Alerts:
The visible alert located on the front panel reads “Service Required.” The audible alert system is internally powered; no batteries are required. When
the indicator lights illuminate or the audible alert sounds, other than during unit start-up, a problem has occurred.
•PowerFailure(Blinkingred“ServiceRequired”lightandpulsingaudiblealert)
•LowFlow(Below0.5lpm)(Continuousred“ServiceRequired”lightandaudiblealert)
•BelowNormalOxygen(84%to75%,yellow“LowOxygen”light.75%to60%,yellow“LowOxygen”lightandbeepingaudiblealert.Lessthan
60%, red “Service Required” light and beeping audible alert.) Refer to Specifications for specific alert settings.
The visible and audible alerts will activate for approximately 15 minutes in a no power situation. If the unit is turned “On” without power or power is
removed later, no alert will sound for the first 10 seconds. After that time, the alert will produce an audible pulse every few seconds while the visible
alert blinks. Power for this alert is provided by a capacitor on the PC board.
NOTE–If the concentrator has been unused for an extended period, the unit must run several minutes before the power fail alert will activate.
The PC (printed circuit) board (Figure 5) is responsible for controlling the system and alerts.
NOTE–Ahighpressureconditionisindicatedbytheaudible(a“popping”sound)releaseofpressurefromapressurereliefvalvelocatedonthe
compressor head.
ROUTINE PATIENT MAINTENANCE
The oxygen patient should perform the following maintenance:
Oxygen Humidifier (reusable bottles only)
The patient should clean the humidifier bottle daily. The patient should follow the instructions supplied by the manufacturer. If no cleaning instructions
were supplied, these steps should be followed:
1. Wash the humidifier bottle in a solution of hot water and dishwashing detergent.
2. Soak the humidifier in a solution of one part white vinegar to three parts hot water for 30-45 minutes. This solution acts as a germicidal agent.
3. Rinse thoroughly with hot tap water and refill with distilled, demineralized, or boiled water for use. Do not overfill.
Cannula/Mask and Tubing
The patient should clean and replace the cannula or mask and tubing as instructed by the manufacturer.
Air Filter and Oxygen Outlet Connector
The air filter and oxygen outlet connector should be cleaned at least once a week by the patient. To clean, these steps should be followed:
1. Remove the air filter located in the door on the back of the unit. Remove the oxygen outlet connector (if used) from oxygen outlet port.
2. Wash in a solution of warm water and dishwashing detergent.
3. Rinse thoroughly with warm tap water and towel dry. The filter should be completely dry before reinstalling.
Do not attempt to operate the unit without the air filter or while the filter is still damp.
NOTE–Theairltershouldbemonitoredmorecloselyinenvironmentswithabnormalamountsofdustandlint.
CAUTION–OperationoftheDeVilbissOxygenConcentratorinextremeenvironmentsorwithouttheairlterwillprematurelyoccludethe
intakebacterialterandcauseadecreaseintheunitperformance.
Exterior Cabinet
The patient should clean the concentrator exterior cabinet by using a damp cloth or sponge with a mild household cleaner and wiping it dry.
Do not apply liquids directly to the cabinet or utilize any petroleum-based solvents or cleaning agents.
WARNING
WARNING

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MAINTENANCE
PERIODIC HOMECARE PROVIDER PREVENTATIVE MAINTENANCE
Every DeVilbiss Oxygen Concentrator is tested at the factory. To assure continued trouble-free performance, the following preventative maintenance
should be performed by the homecare provider during periodic oxygen patient visits. Failure to properly maintain the unit will void the warranty.
1. Check the oxygen concentration with an oxygen analyzer (part #O2ANA)—every two years.
a. Calibrate the oxygen analyzer prior to checking the oxygen concentration. The analyzer should be properly calibrated using the
manufacturer’s recommended procedure.
NOTE–Changesintemperature,altitude,orhumiditymayaffecttheanalyzer’soxygenconcentrationreading.Theanalyzershouldbe
calibrated in similar conditions to the location of the concentrator.
b. Set the flow meter to 5 LPM. The concentrator must operate for a minimum of 20 minutes before checking the oxygen concentration.
c. Connect the analyzer to the unit’s oxygen outlet port and wait until the display stabilizes.
d. Record the reading.
2. Check the audible alert and indicator lights every two years. When the power switch is turned “On,” listen for the audible alert and check to see if
the front panel indicator lights are operating.
3. Inspect intake filter (part #MC44D-605) every 2 years or 8.760 hours. Replace as necessary.
a. Open the filter door and replace filter as required.
4. Inspect the final bacteria filter (part #PV5LD-651) every 3 years or 17.500 hours. Replace as necessary or in conjunction with compressor service.
a. Unplug the unit, remove the cabinet, and loosen the bib.
b. Remove the hose from each end of the filter and discard the filter.
c. Install the new final bacteria filter with the “IN” fitting toward the flow meter.
d. Tighten the bib and replace the cabinet.
5. Inspect the compressor filter (part #525D-622) every 5 years. Replace as necessary or in conjunction with compressor service.
NOTE–This PM Schedulereects:
•5000hourusageequaltooneyear
•anormal,cleanoperatingenvironment.
The homecare provider is responsible for:
 •determiningtheconditionoftheconcentratoroperatingenvironment.
 •determiningapreventativemaintenanceintervalfrequency*whichtakesintoconsiderationthespecicoperatingenvironment.
  *Standardintervalsarenotedbelow.ServiceintervalmaybemoreorlessfrequentthanstatedbelowprovidedthattheHomeCare
Provider establishes and documents appropriate protocols.
BETWEEN PATIENT MAINTENANCE
1. Discard oxygen tubing, cannula & humidifier bottle.
2. Wash or replace the cabinet air filter.
3. Wash the concentrator cabinet.
4. Check oxygen concentration. If the unit falls within specification, the extended life intake bacteria filter does not need to be replaced between
patients.
PREVENTATIVE MAINTENANCE SUMMARY
Patient
Daily Clean the humidifier bottle (if used).
Weekly Clean air filter on back of unit.
Clean exterior of cabinet.
Other Clean and replace cannula/mask and tubing as instructed by manufacturer.
Homecare Provider
2 years Inspect/Replace intake bacteria filter as necessary.
Check audible alert and indicator lights.
Check oxygen concentration.
Wash/Replace cabinet filter.
3 years Inspect/Replace final bacteria filter.
5 years Inspect/Replace the compressor filter.

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TROUBLESHOOTING
SYSTEM OPERATION
The DeVilbiss Oxygen Concentrator uses a pressure swing adsorption system. The air is drawn into the unit through air filters and into a double-head
compressor.
A pneumatic diagram of the system is shown in Figure 17.
The compressed air passes through a rotary valve (Figure 5), which is cycled at a pre-determined rate, and is directed into one of two sieve beds. The
sieve beds contain molecular sieve material which is a synthetically-produced inorganic silicate. It is very porous and has the unique ability to selectively
adsorb nitrogen from the air as it passes through the sieve bed.
As one bed is being pressurized, the other bed is quickly depressurized. This allows the nitrogen that was adsorbed during its pressurization cycle to be
exhausted from the sieve material.
The nitrogen is released through exhaust ports located on the rotary valve assembly. The ports are connected to a single piece of hose running from
the valve to the exhaust muffler.
Also during each bed pressurization, a small amount of oxygen flows through an orifice (Figure 6) from the pressurized bed into the depressurizing bed.
The orifice is clamped inside a long piece of blue tubing connecting the outlets of the two sieve beds. This helps purge the nitrogen from the
depressurizing bed.
The beds will continue to be alternately pressurized and depressurized as the unit operates.
Oxygen leaving the sieve beds is directed through a check valve to the accumulator tank. A pressure regulator (Figure 9) on the tank controls the
oxygen pressure as it leaves the accumulator and enters the flow meter. The flow meter allows the oxygen flow to be controlled and adjusted to the
level prescribed by the patient’s physician. From the flow meter the oxygen passes through the final bacteria filter (Figure 10), a check valve, and finally
the oxygen outlet port to the patient.
The DeVilbiss Oxygen Concentrator operates on a timed cycle. The cycling is controlled by the PC board. The PC board will send voltage to the valve
causing it to shift and alternately pressurize the sieve beds.
The PC board also activates the electronic alert system. A high pressure condition will be indicated with a “popping” type sound produced by release of
pressure from a pressure relief valve on the compressor head. Low flow, system abnormality, and power failure are indicated by audible and visible
alerts.
The 525 Model operating system incorporates “turn-down” technology. The PC board constantly monitors the flow rate and will decrease the cycle
time whenever the flow rate is less than 2.5 LPM. Therefore it “turns-down” the cycle based on lower oxygen demand. As a result, the unit runs cooler
and less power is consumed.
NORMAL OPERATING SEQUENCE
When the concentrator is turned “On,” the following cycling sequence can be observed by attaching pressure gauges to the sieve bed test points.
1. The rotary valve is quickly cycled several times to relieve residual bed pressure preventing a static condition in the compressor. This rapid cycling
only happens on start-up and is clearly heard as pressure is being quickly exhausted several times through the exhaust muffler that is connected to
the valve.
2. The PC board applies a short DC voltage signal to the valve. The valve will stop for several seconds causing the right bed to pressurize first while
the left bed depressurizes to approximately 2 PSI (14 kPa).
3. Voltage is again applied to the valve for a short time. The valve will stop for approximately a second. During this time the sieve bed pressures are
equalized.
4. A short DC voltage signal is again applied to the valve. The valve will stop for several seconds causing the left bed to pressurize while the right bed
depressurizes to approximately 2 PSI (14 kPa).
5. A short DC voltage signal is again applied to the valve. The valve will stop for approximately a second. During this time, the sieve bed pressures
are equalized.
6. The cycle then repeats with step 2.
NOTE–Inthe“turn-down”mode,thexedcycletimeisdecreasedtoafewsecondsandthebedpressureequalizationtimetolessthanasecond.
NOTE–High-endsievebedpressureshouldnotexceed1/2PSI(4kPa)abovehigh-endaccumulatorpressures.RefertoSpecicationsfornormal
pressures obtained during the cycle.

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TROUBLESHOOTING
SIMPLIFIED TROUBLESHOOTING
The key to simple troubleshooting is to recognize which type of problem exists and select the most effective approach to solving the problem. The
different types of problems and the approaches for solutions are as follows:
Type I—The unit runs but a low pressure and flow or high pressure condition exists.
NOTE–Lowpressureorowareindicatedbybothavisibleandaudiblealarm.Highpressureisindicatedbya“popping”soundcausedbythe
pressure relief valve.
1. Connect test gauges to sieve bed tests points (Figure 9).
2. Refer to the Normal Operating Sequence to make sure the unit is cycling properly.
3. If bed pressure is rising slowly, check for occluded filters and severe leaks. If filters are clean and there are no leaks, then the compressor is
defective.
4. If the pressure relief valve is releasing pressure, observe whether the unit is cycling or not.
5. If the unit is not cycling or has uneven bed pressures, this indicates that the rotary valve is not operating correctly. Refer to the Rotary Valve Testing
described in the chapter Component Testing, Repair and Replacement.
6. If the unit is cycling in conjunction with very high bed pressures, this indicates defective sieve beds.
Type II—The compressor will not start when the unit is turned on.
1. Verify that the cooling fan is running; if it is not, determine where you are losing power.
2. Check for compressor voltage at the compressor connector.
3. If voltage is present, then the capacitor or compressor is defective.
4. If voltage is not present, the wire harness is defective.
Electric Shock Hazard. Extra care should be taken if it is necessary to operate the unit with the cabinet removed.
Mechanical Hazard. Keep fingers, loose clothing, etc. away when working on compressor.
Type III—The concentrator runs and continues to cycle but has low oxygen concentrations.
1. Connect test gauges and check for higher or lower than normal bed pressures.
a. High pressures indicate defective sieve beds.
b. Low pressures indicate occluded filters, leaks, or defective compressor.
c. Uneven bed pressures indicate valve is not operating correctly.
2. Check for oxygen leaks at:
 • sievebeds • owmeter
 • accumulatortank • nalbacterialter
 • pressureregulator • nalcheckvalve
 • outletport
NOTE–CheckforleaksusingacertiedleakdetectionsolutionsuchasSnoop®orequivalent(mustnotcontainethyleneglycol).Applyleaktest
solutiontoallttingsandhoseconnectionswithunitrunning.Ifanairleakispresent,thesolutionwillbubble.Allleaksshouldberepaired
before putting the unit back in service.
CAUTION–Do not apply leak test solution to any part of the rotary valve or the main PC Board assembly.
3. Test accumulator tank pressure. If pressure is lower than normal, then sieve bed check valves are defective.
NOTE–FornormalsystempressuresrefertoSpecications.
WARNING
WARNING

LT-2023
10
TROUBLESHOOTING CHART A
Visible Alarm Audible Alarm Compressor Power Light
OFF OFF ON ON
Other Symptoms Possible Cause Possible Remedy
Pulsating air noise Intake filter not in place or defective Check filter and replace if necessary
Compressor intake hose disconnected Reconnect hose
Excessive noise Loose or defective motor mounts Replace motor mounts
Defective compressor Replace compressor
Defective cooling fan Replace cooling fan
Fluctuating oxygen flow Occluded humidifier Clean or replace humidifier
Use of improper humidifier Use only a bubble-type humidifier
Occluded filters Clean or replace filters
Occluded or defective cannula and tubing Detach cannula from oxygen delivery tubing. If
proper flow is not attained, check tubing for
kinks or other obstructions. Clean or straighten
as required or replace tubing if necessary.
Use of excess oxygen tubing The unit is designed to deliver 5 lpm with a
cannula on 50 feet (15 meters) of approximately
5/32” (4 mm) inside diameter tubing. Smaller
diameter tubing or the addition of any other
flow restriction may prevent obtaining the
desired flow rate.
Defective flow meter Replace flow meter
Leak in system Check for leaks in all hoses and fittings
Defective compressor Replace compressor
Defective compressor reed valve Replace compressor reed valve
Defective check valve Replace check valve
Pressure regulator not adjusted Adjust or replace pressure regulator
properly or defective
Little or no oxygen flow Flow meter not adjusted properly Adjust flow meter
Hose disconnected to flow meter Reconnect hose
Oxygen delivery tubing is kinked or blocked Straighten tubing or remove obstruction
Occluded humidifier Clean or replace humidifier
Low oxygen concentration Leak in system Check for leaks in all hoses and fittings
Defective sieve bed check valve Replace check valve
Defective compressor reed valve Replace compressor reed valve
Defective compressor Replace compressor
Rotary valve not operating correctly Replace valve
Occluded filters Clean or replace filters
Contaminated sieve beds Replace sieve beds
Audible alarm does not Unit has not been used for an extended Allow unit to run for 20 minutes and retry
sound during power failure period of time. NOTE–If the concentrator
has been unused for an extended period,
the unit must run several minutes before
the power fail alarm will activate.
Defective PC board Replace PC board
Defective power switch Replace power switch
Defective wire harness Replace wire harness
Audible alarm does not sound when Defective PC board Replace PC board
unit is turned “On”
Pressure relief valve activated - PC board connectors not properly latched Be sure tabs are pushed completely into place
“popping” sound Defective PC board Replace PC board
Defective rotary valve Replace valve
Service Required light does not PC board connectors not properly latched Be sure tabs are pushed completely into place
illuminate when unit is turned “On” Defective PC board Replace PC board
Defective light Replace light
TROUBLESHOOTING