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Oxygen concentrators · Concentrator Platinum family

Invacare 3LX: troubleshooting and error codes

The ServiceForge knowledge base holds 14 documented symptoms for the Invacare 3LX, with 46 ranked causes, 6 diagnostic checks with test points and expected values, and 0 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Low oxygen concentration patient safety

Unit produces oxygen below specification. Status indicators: 73% Shutdown (RED 2 Flash, GREEN 1 Flash) or 85% Shutdown (RED 2 Flash, GREEN 2 Flash) on Integrated Sensor. SensO2 units show RED On for critical low purity with continuous alarm. Normal low purity shows YELLOW On.

Ranked causes

  1. 1. Cabinet filters dirty (common)
  2. 2. Inlet filter dirty (common)
  3. 3. Compressor defective or worn (occasional)
  4. 4. Heat exchanger leak or fouling (occasional)
  5. 5. Relief valve leaky or defective (occasional)
  6. 6. Insufficient power supply voltage (occasional)
  7. 7. Fan not operating or faulty (occasional)
  8. 8. Sieve beds defective (occasional)
  9. 9. Tubing kinked or blocked (common)
  10. 10. P.C. board wrong pressure shifts (occasional)
  11. 11. Exhaust muffler dirty or plugged (common)
First check

Measure pressure at product tank at shift point

Test point
product tank
Expected
rise to 20 p.s.i. at shift point
Tools
pressure gauge

11 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit overheats caution

Unit reaches excessive temperature during operation; base exhaust or cabinet airflow restricted

Ranked causes

  1. 1. Base exhaust vent plugged or restricted (common)
  2. 2. Cabinet filters dirty or blocked (common)
  3. 3. Fan disconnected, defective, or installed backwards (occasional)
  4. 4. Heat exchanger fins dirty or damaged (common)
  5. 5. Compressor defective, faulty capacitor, bad motor windings, or worn seals (occasional)
  6. 6. Line voltage excessive (surge) (rare)
First check

Verify unit position and clearance

Test point
Unit location and surroundings
Expected
Unit at least 3 inches from walls, not on carpeting

10 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

High pressure alarm caution

Unit pressurizes abnormally high, indicated by continuous system indicators

Ranked causes

  1. 1. 4-way valve malfunction (occasional)
  2. 2. Sieve beds contaminated (occasional)
  3. 3. Inlet filter dirty or plugged (common)
  4. 4. Compressor malfunction (occasional)
  5. 5. Heat exchanger leak or damage (occasional)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit does not power on

Unit plugged in, power switch on, alarm off. Internal status indicators RED and GREEN both off. Battery Free circuit drained.

Ranked causes

  1. 1. No power at outlet (common)
  2. 2. Power cord frayed or damaged (occasional)
  3. 3. Power cord connector loose or disconnected inside unit (occasional)
  4. 4. On/Off switch disconnected wire (occasional)
  5. 5. On/Off switch faulty (occasional)
First check

Verify power at outlet

Test point
Wall outlet
Expected
150-200 VAC
Tools
Tablelamp or voltmeter

6 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit excessively loud caution

Noise level unusually high during operation; muffler, resonator or intake filter issue

Ranked causes

  1. 1. Pneumatic exhaust muffler damaged, missing or tubing disconnected (common)
  2. 2. Intake resonator damaged, missing or tubing disconnected (common)
  3. 3. Inlet filter missing (occasional)
  4. 4. Compressor internal damage (rare)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Compressor not operating with power on caution

Fan operates and power light on, but compressor does not run. No alarm or red/yellow indicators on control panel

Ranked causes

  1. 1. Circuit breaker tripped (common)
  2. 2. Transformer assembly faulty or connector loose (occasional)
  3. 3. PC Board faulty (occasional)

3 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit not operating, no alarms, all indicators off caution

Concentrator does not start; no power or status indication; all internal and control panel indicators off; purity switch at 73% or 85%

Ranked causes

  1. 1. Purity switch defective (common)
  2. 2. Transformer assembly molex connector disconnected or faulty (common)
  3. 3. Horn connector disconnected (occasional)

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Low pressure alarm caution

Unit fails to build adequate pressure. Compressor shuts down with continuous audible alarm. Internal indicators: RED On, GREEN On (LX Control) or RED 1 Flash, GREEN 1 Flash (Integrated Sensor)

Ranked causes

  1. 1. Regulator cracked or leaking (occasional)
  2. 2. P.E. valve leaking (occasional)
First check

Measure voltage at P.E. valve connector on 24V DC scale

Test point
P.E. valve connector
Expected
approximately 24 volts V
Tools
DMM (24V DC scale)

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit alarm continuous with high pressure shutdown patient safety

Compressor shut down, continuous alarm. Internal status RED on/no green. Control panel RED on, YELLOW and GREEN off. High pressure detected

Ranked causes

  1. 1. PC Board malfunction or disconnected wire (common)
  2. 2. 4-way valve not shifting or shifting at high pressure (occasional)

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Fluctuating flow

Oxygen flow rate unstable or varying; regulator or flowmeter malfunction causing inconsistent output

Ranked causes

  1. 1. Regulator incorrectly set or flowmeter malfunction (common)
First check

Check oxygen outlet pressure

Test point
oxygen outlet
Expected
5 p.s.i. + 0.2 max, +/- 0.2

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Low concentration (continued) patient safety

Oxygen concentration below acceptable level; dirty or plugged bacteria filter restricting flow

Ranked causes

  1. 1. Bacteria filter dirty or plugged (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Oxygen purity: Good but indicators not illuminating

Unit operates normally and maintains proper oxygen purity but green or yellow panel indicator does not illuminate after 30 minutes

Ranked causes

  1. 1. PC Board defective (occasional)
First check

Allow unit to run 30 minutes at configured purity setting

Test point
Panel indicators and purity setting
Expected
Green or Yellow indicator illuminates after 30 minute run time

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit not operating with continuous audible alarm caution

Concentrator does not operate when power switch on; continuous audible alarm present; all panel indicators off

Ranked causes

  1. 1. Internal repairs required (unknown)

Unit not operating with red flashing 3 times, green flashing 1 time caution

Concentrator does not operate; internal indicators show 3 red flashes and 1 green flash; control panel yellow flashing, green on

Ranked causes

  1. 1. SensO2 circuit board defective or failure (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Community

0 fixes logged by technicians through their AI, with outcomes, for this model.

ServiceForge knowledge base record. Field-unverified unless technicians confirmed it. A teaching summary of the record, not a service manual. Export 2026-10-14.