Ventilators

Impact Instrumentation Uni-Vent 754: troubleshooting and error codes

The ServiceForge knowledge base holds 347 documented symptoms for the Impact Instrumentation Uni-Vent 754, with 362 ranked causes, 730 diagnostic checks with test points and expected values, and 80 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Audible alarm comes on continuously patient safety

Continuous audible alarm activation during ventilator operation or failure conditions

Ranked causes

1. Failure Code 5: Excessive airway pressure above 40 cmH2O for 4 seconds (common)
2. Failure Code 2: No gas supply (COMP alarm) (occasional)
3. Failure Code 1: Self check failure during startup (rare)
4. Failure Code 3: Excessive airway pressure during startup (rare)
5. Failure Code 4: Memory check failure (rare)

First check

Verify airway pressure level

Test point: Airway pressure transducer
Expected: Should be below 40 cmH2O
Tools: Pressure gauge or syringe manometer

2 more checks with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarm mute does not restore after 30 seconds patient safety

After pressing Mute/Cancel, alarm remains silent or LED remains solid beyond 30-second period

Ranked causes

1. Alarm condition not resolved before mute timeout (common)
2. Mute/Cancel button not functioning (rare)

First check

Verify alarm condition exists and measure time from Mute/Cancel button press

Test point: Alarm LED and audible alarm output
Expected: LED goes from blinking to solid; alarm sound stops for 30 seconds; both resume after 30 seconds

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

Charge LED does not illuminate

LED fails to light after external power supply connected and battery disconnected

Ranked causes

1. External power supply not connected or faulty (common)
2. Dummy load not in place (occasional)

First check

Verify external power supply connected

Test point: External power connector
Expected: Power supply plugged in and active

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

Comp alarm occurs with external air switchover patient safety

Compressor alarm triggered during switching between external air and compressor operation, occurring simultaneously with possible Vt and Disconnect alarms.

Ranked causes

1. Compressor fails to start during switchover from external air (occasional)
2. External gas supply pressure below 35 PSI +/- 2 PSI (occasional)

First check

Verify external gas supply pressure

Test point: External air inlet pressure gauge
Expected: >=35 PSI +/- 2 PSI, +/- 2 PSI

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

External Power Fail alarm does not clear when Mute/Cancel pressed patient safety

After pressing Mute/Cancel during External Power Fail alarm, alarm LED remains on or audible alarm continues

Ranked causes

1. External power not restored (common)
2. Mute/Cancel button malfunction (occasional)

First check

Verify external power connection status

Test point: Main power input connector
Expected: External power connected and supplying voltage

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Failure Code 2 alarm verification patient safety

Verification test for COMP (No Gas) alarm functionality during gas supply loss

Ranked causes

1. Loss of external air supply (common)
2. Loss of oxygen supply (common)

First check

Establish COMP alarm condition

Test point: Gas supply inlet connections
Expected: COMP alarm triggered when supplies are disconnected

1 more check with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Manual Breath button does not deliver breath patient safety

Pressing Manual Breath button does not produce audible beep or generate control breath at specified settings

Ranked causes

1. Manual Breath button pressed at wrong time in breath cycle (common)
2. Manual Breath button malfunction or circuit failure (occasional)

First check

Press Manual Breath button during expiratory pause

Test point: Manual Breath push-button control
Expected: Audible beep heard and control breath generated

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Manual Breath generates no control breath patient safety

Pressing Manual Breath button during expiratory pause produces beep but no breath delivery from unit

Ranked causes

1. Hose circuit not properly connected to test lung (common)
2. Incorrect mode or rate settings (occasional)

First check

Verify hose circuit connected to test lung

Test point: Hose circuit inlet
Expected: Secure connection with no leaks visible

1 more check with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

System Failure LED and audible alarm do not activate caution

LED does not come on solid and continuous audible tone not heard when both fuses are removed

Ranked causes

1. Bottom fuse not removed or not fully seated (common)
2. Top fuse not removed (occasional)

First check

Verify top fuse removed

Test point: Top fuse location
Expected: Fuse absent

1 more check with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

System Failure LED does not come on or LCD screen does not blank caution

LED fails to illuminate solid or screen does not go blank after both fuses are removed and alarm muted.

Ranked causes

1. Audible alarm not giving continuous tone (occasional)
2. Unit not shutting down after fuse removal (occasional)

First check

Observe System Failure LED state

Test point: System Failure LED indicator
Expected: LED comes on solid

3 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

System Failure LED does not come on solid caution

LED fails to illuminate when both top and bottom fuses are removed with unit in AC mode.

Ranked causes

1. Top fuse not removed before bottom fuse removal (common)
2. Bottom fuse not removed after top fuse removal (common)

First check

Verify unit is in A/C mode with external power and battery connected

Test point: Unit mode indicator
Expected: A/C mode displayed

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Total Flow Backup Alarm does not occur patient safety

During partial compression inlet occlusion test with tidal volume less than half set volume, alarm should trigger after 4-5 breaths but does not

Ranked causes

1. Compressor inlet partially occluded incorrectly or insufficient occlusion (common)
2. Alarm detection circuit malfunction (rare)

First check

Set ventilator parameters to test values

Test point: Control panel settings
Expected: Rate=15 BPM, I time=1.0 sec, Vt=900 ml, FIO2=21%, External Air=OFF

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Air/Oxygen Mixer control inoperative patient safety

Air/Oxygen Mixer setting cannot be changed or does not affect delivery mixture

Ranked causes

1. Air/Oxygen Mixer control or LCD display failure (unknown)

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

Alarm cannot be muted or alarm LED/audible does not turn off

Mute/Cancel button should silence LED and audible for Vt Settings alarm while message remains

Ranked causes

1. Mute/Cancel button malfunction (rare)

First check

Press Mute/Cancel button

Test point: Mute/Cancel push-button
Expected: Button responds to press

3 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarm deactivation after disconnect cleared

When disconnect condition is fixed, alarm should fully deactivate including LED and audible alert

Ranked causes

1. Disconnect condition resolved (common)

First check

Restore disconnect condition

Test point: Circuit connection
Expected: Hose/circuit reconnected

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarm LED and audible should turn off after Mute/Cancel

LED and audible alert silence when Mute/Cancel button is pressed while alarm is active

Ranked causes

1. Normal alarm mute function operation (common)

First check

Activate alarm and press Mute/Cancel

Test point: Mute/Cancel push-button
Expected: LED and audible turn off; AMC message remains

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

Alarm LED behavior during mute/cancel

LED should transition from blinking to solid on for 30 seconds, then return to blinking after mute is released or timeout occurs

Ranked causes

1. Mute/Cancel button pressed while alarm active (common)

First check

Verify alarm LED transitions to solid on when Mute/Cancel pressed

Test point: Alarm LED indicator
Expected: LED changes from blinking to solid on

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarm LED blinking and solid response

Alarm LED should blink when a Disconnect alarm is generated, then turn solid after Mute/Cancel button is pressed.

Ranked causes

1. Disconnect alarm condition detected (common)

First check

Generate Disconnect alarm condition

Test point: Patient circuit connection
Expected: Alarm LED blinking

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarm LED does not blink on Disconnect alarm

LED fails to respond when Disconnect alarm is generated

Ranked causes

1. Alarm not generated or patient circuit properly connected (common)

First check

Verify patient circuit disconnected from test lung

Test point: Patient circuit connection
Expected: Circuit completely disconnected

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

Alarm LED does not come on solid when muted

LED fails to remain solid after Mute/Cancel button is pressed during disconnect alarm.

Ranked causes

1. Mute/Cancel button not functioning (occasional)

First check

Press Mute/Cancel push-button during active alarm

Test point: Mute/Cancel button
Expected: Alarm LED transitions to solid state

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

Alarm LED does not remain solid after Mute/Cancel pressed

Alarm LED fails to change from blinking to solid state after Mute/Cancel button is pressed during Disconnect alarm

Ranked causes

1. Mute/Cancel push-button not functioning (occasional)

First check

Press Mute/Cancel push-button during active Disconnect alarm

Test point: Mute/Cancel push-button
Expected: Alarm LED transitions from blinking to solid

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

Alarm LED does not respond to disconnect condition patient safety

Alarm LED fails to blink when disconnect alarm is generated or does not come on solid when Mute/Cancel is pressed

Ranked causes

1. Patient circuit disconnected from test lung (common)

First check

Remove patient circuit from test lung

Test point: Patient circuit connection
Expected: Circuit disconnected

3 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarm LED does not transition between states during mute

Alarm LED should transition from blinking to solid on when Mute/Cancel is pressed, remain solid for 30 seconds, then return to blinking

Ranked causes

1. Alarm LED control logic malfunction (unknown)

First check

Observe Alarm LED during mute activation

Test point: Alarm LED
Expected: Transitions from blinking to solid on

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarm LED does not transition to solid state when alarm muted

Alarm LED does not change from blinking to solid on state when Mute/Cancel button is pressed

Ranked causes

1. Alarm LED control circuit malfunction (unknown)

First check

Verify alarm LED state during mute cycle

Test point: Alarm LED indicator
Expected: LED should transition from blinking to solid on for 30 seconds, then resume blinking

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

Alarm LED does not turn off after Cancel button during External Power Fail

LED remains lit or blinking after pressing Cancel button during External Power Fail alarm

Ranked causes

1. LED control circuit not responding to Cancel command (unknown)

First check

Verify alarm LED turns off after Cancel button press

Test point: Alarm LED indicator
Expected: LED turns completely off

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

Alarm LED does not turn off after disconnect condition fixed patient safety

Alarm LED remains on after patient circuit is reconnected and disconnect condition is resolved

Ranked causes

1. Disconnect condition not fully resolved (common)

First check

Reconnect patient circuit to test lung

Test point: Patient circuit connection
Expected: Positive airway pressure rise is sensed on next breath

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

Alarm LED does not turn off after disconnect is corrected

LED remains on after patient circuit is reconnected to test lung.

Ranked causes

1. Patient circuit not properly connected or breath not fired (common)

First check

Reconnect patient circuit to test lung

Test point: Patient circuit connection
Expected: Circuit fully connected

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

Alarm LED does not turn off when External Power Fail alarm canceled

Alarm LED remains on or does not turn off when Mute/Cancel button is pressed during External Power Fail alarm

Ranked causes

1. LED control circuit does not respond to cancel command (unknown)

First check

Verify alarm LED turns off when cancel pressed

Test point: Alarm LED indicator
Expected: LED should turn off

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

Alarm Message Center continues displaying alarm after mute

Alarm Message Center still shows Disconnect alarm when Mute/Cancel button is pressed during muting operation

Ranked causes

1. Alarm mute function behavior as designed (common)

First check

Confirm Alarm Message Center display persists during mute

Test point: Alarm Message Center display
Expected: Should still display the Disconnect alarm

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

Alarm Message Center display during mute patient safety

AMC should continue displaying the active alarm condition even while audible alarm is muted

Ranked causes

1. Mute function active while alarm condition persists (common)

First check

Verify AMC displays alarm message while mute active

Test point: Alarm Message Center display
Expected: Disconnect alarm message displayed

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

Alarm Message Center does not clear after cancel

Alarm Message Center displays alarm message even after cancel function is activated during External Power Fail condition

Ranked causes

1. Display control circuit does not clear alarm display on cancel (unknown)

First check

Verify Alarm Message Center clears on cancel

Test point: Alarm Message Center display
Expected: Should show no alarm

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

Alarm Message Center does not display Disconnect alarm during Mute patient safety

AMC display is blank or shows different alarm while Disconnect condition is active and muted

Ranked causes

1. AMC display circuit not updating correctly (unknown)

First check

Verify Alarm Message Center displays Disconnect alarm while muted

Test point: AMC display
Expected: Disconnect alarm message visible during 30 second mute period

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

Alarm Message Center does not display during mute

When alarm is muted using Mute/Cancel button, the Alarm Message Center should continue displaying the alarm condition

Ranked causes

1. Alarm Message Center display not updating during mute condition (unknown)

First check

Observe Alarm Message Center display during mute period

Test point: Alarm Message Center display
Expected: Disconnect alarm message displayed

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

Alarm mute/cancel not responding

Mute/Cancel button should silence audible alarm for 30 seconds and toggle alarm LED from blinking to solid, or fully cancel alarm and turn off alarm LED

Ranked causes

1. Mute/Cancel button not functional or electrical issue with alarm circuit (common)

First check

Generate Disconnect alarm and press Mute/Cancel button

Test point: Mute/Cancel push-button control
Expected: Audible alarm mutes for 30 seconds; LED changes from blinking to solid

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarms cancel on Vt adjustment patient safety

Alarms clear when tidal volume setting decreased to 500 ml

Ranked causes

1. Tidal volume setting corrected to within acceptable range (common)

First check

Verify alarms cleared

Test point: Ventilator display and audio
Expected: All alarms cancel

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

Alarms cancel when oxygen concentration set to 21% patient safety

O2 Low/Fail and FIO2 alarms clear when FIO2 set to room air level

Ranked causes

1. Low oxygen pressure alarm requires higher FIO2 setting (common)

First check

Verify alarms cancel

Test point: Alarm display and audible
Expected: All alarms cleared

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

Alarms cancel when tidal volume decreased to 500 ml patient safety

All alarms clear when tidal volume setting is decreased to 500 ml from elevated levels

Ranked causes

1. Tidal volume setting 500 ml below alarm thresholds (common)

First check

Decrease tidal volume to 500 ml and verify alarms cancel

Test point: Tidal volume setting
Expected: All alarms cancel ml

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

Alarms cancel when tidal volume reduced patient safety

All tidal volume-related alarms cancel when Vt setting is decreased to 500 ml

Ranked causes

1. Tidal volume within normal operating range (common)

First check

Decrease tidal volume to 500 ml

Test point: Vt control
Expected: 500 ml

Alarms cancel when tidal volume returns to normal patient safety

All alarms clear when Vt setting is reduced to 500 ml

Ranked causes

1. Tidal volume within safe limits (common)

First check

Alarm cancellation at low Vt

Test point: alarm status
Expected: All alarms cancel ml

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

Alarms cancel when tidal volume setting is decreased patient safety

All alarms clear when tidal volume is decreased to 500 ml from elevated setting

Ranked causes

1. Tidal volume setting returned to acceptable range (common)

First check

Decrease tidal volume setting

Test point: Vt control
Expected: 500 ml

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

Alarms cancel when Vt decreased to 500 ml patient safety

All tidal volume alarms clear when setting returned to safe range

Ranked causes

1. Tidal volume setting outside safe operating range (common)

First check

Verify tidal volume alarms clear

Test point: Alarm display
Expected: All alarms cancelled

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

Alarms cancel when Vt setting reduced patient safety

Alarms are canceled when tidal volume setting is decreased to 500 ml, which is within acceptable range

Ranked causes

1. Tidal volume setting decreased to 500 ml (within acceptable range) (common)

First check

Verify alarms cancel at Vt setting of 500 ml

Test point: Tidal volume setting control
Expected: Alarms should cancel

Alarms do not cancel when oxygen concentration set to 21% patient safety

Alarms should clear when FIO2 is lowered to 21%

Ranked causes

1. Oxygen concentration at 21% with low tank pressure (common)

First check

Set oxygen concentration

Test point: FIO2 control
Expected: 21%

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarms do not cancel when oxygen tank pressure returned to normal patient safety

Alarms should clear when oxygen tank pressure is restored to 45 PSI +/- 2 PSI

Ranked causes

1. Oxygen tank pressure restored to normal operating level (common)

First check

Restore oxygen tank pressure

Test point: Oxygen tank pressure
Expected: 45 PSI +/- 2 PSI, +/- 2 PSI

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarms do not cancel when tidal volume reduced to safe level patient safety

When tidal volume decreased to 500 ml, all alarms should clear

Ranked causes

1. Alarm cancellation logic malfunction for tidal volume (unknown)

First check

Decrease tidal volume to safe level

Test point: Vt control
Expected: 500 ml

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarms do not cancel when Vt decreased to 500 ml patient safety

All alarms should clear when tidal volume is reduced to 500 ml

Ranked causes

1. Tidal volume within normal range at 500 ml (common)

First check

Decrease tidal volume setting

Test point: Vt control
Expected: 500 ml

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Alarms do not recur when oxygen concentration returned to 60% patient safety

O2 Low/Fail and FIO2 alarms should re-trigger when FIO2 is increased to 60% with tank pressure at 35 PSI

Ranked causes

1. Oxygen concentration increased to 60% with low tank pressure (common)

First check

Increase oxygen concentration to 60%

Test point: FIO2 control
Expected: 60%

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

AMC message does not remain displayed during test procedures caution

AMC indicator message fails to stay on display after Mute/Cancel button is pressed

Ranked causes

1. Display circuit or AMC indicator logic malfunction (unknown)

First check

Observe AMC message persistence after alarm cancellation

Test point: LCD display
Expected: AMC message remains visible after Mute/Cancel button press

Audible alarm does not give continuous tone when both fuses removed

Audible alarm fails to produce continuous tone when both fuses are removed from the unit

Ranked causes

1. Both fuses not removed (common)

First check

Verify both fuses removed

Test point: Top and bottom fuse locations
Expected: Both fuses out

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Audible alarm does not mute when Mute/Cancel button pressed

Pressing Mute/Cancel button does not silence the audible alarm during a Disconnect alarm condition

Ranked causes

1. Mute/Cancel button not functioning (unknown)

First check

Verify Mute/Cancel button silences audible alarm

Test point: Mute/Cancel push-button control
Expected: Audible alarm should mute for 30 seconds

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

Audible alarm does not sound at low voltage

Audible alarm should sound continuously when external power voltage drops below shutdown threshold (9.5V–10.5V)

Ranked causes

1. External power voltage drops below 9.5V–10.5V shutdown threshold (common)

First check

Lower voltage to shutdown range and verify audible alarm

Test point: External power jack, audio output
Expected: Audible alarm sounds continuously at 9.50V–10.50V, –10.50V
Tools: Variable power source, DMM

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

Audible alarm does not sound continuously on shutdown

When system voltage drops below threshold and unit shuts down, audible alarm fails to come on continuously as expected.

Ranked causes

1. Low voltage causes system shutdown without alarm activation (unknown)

First check

Verify system shutdown voltage range

Test point: External power jack input
Expected: 8.5V - 9.3V, 8.5–9.3V
Tools: Variable power source, DMM

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Audible alarm does not sound continuously with both fuses removed caution

Continuous tone audible alarm fails to sound when both top and bottom fuses are removed

Ranked causes

1. Both fuses not removed (common)

First check

Confirm both top and bottom fuses are removed

Test point: Fuse holders (top and bottom)
Expected: Both fuses absent

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

Audible alarm does not stop after mute

User presses Mute/Cancel button but alarm continues to sound; alarm LED behavior and message center state vary depending on alarm type

Ranked causes

1. External Power Fail alarm not properly canceled (common)

First check

Verify alarm type and mute button response

Test point: Mute/Cancel push-button control
Expected: Audible alarm stops and alarm LED turns off

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Audible alarm mute function

Audible alarm should mute for 30 seconds when Mute/Cancel button pressed, then resume after timeout

Ranked causes

1. Mute/Cancel button activated during active alarm (common)

First check

Verify audible alarm mutes when Mute/Cancel pressed

Test point: Speaker/audible output
Expected: Alarm sound ceases

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Audible alarm mutes temporarily instead of stopping

After pressing Mute/Cancel, alarm silences for 30 seconds then resumes; alarm LED transitions from blinking to solid for 30 seconds then blinks again

Ranked causes

1. Disconnect alarm pending; mute function working as designed (common)

First check

Generate Disconnect alarm and press Mute/Cancel

Test point: Mute/Cancel push-button control
Expected: Audible alarm mutes for 30 seconds; alarm LED transitions from blinking to solid for 30 seconds

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Audible alarm not producing expected pulse pattern

Audible alarm does not produce the expected 4 to 5 pulse repeating alarm pattern when expected to sound.

Ranked causes

1. Audible alarm circuit or speaker defective (unknown)

Backlight does not respond to ambient light

Backlight threshold adjustment needed; backlight should turn off in darkness and on when sensor is covered

Ranked causes

1. Backlight threshold requires calibration (common)

First check

Enter User Program Mode

Test point: LCD menu
Expected: Menu appears at top of LCD

4 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Backlight does not respond to sensor

Backlight does not turn off when sensor is uncovered or turn on when covered, indicating backlight sensor or threshold calibration issue

Ranked causes

1. Backlight threshold not properly calibrated (common)

First check

Enter User Program Mode

Test point: LCD menu
Expected: Menu appears along top of LCD

2 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Backlight sensor calibration

Backlight threshold must be set so the display backlight responds to ambient light levels appropriately.

Ranked causes

1. Backlight threshold not calibrated to user environment (unknown)

First check

Enter User Program Mode

Test point: Unit controls
Expected: Menu appears along top of LCD

4 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

More symptoms

Backup ventilation flow rate below specification
Backup ventilation inspiratory time out of specification
Backup ventilation rate out of specification
Backup ventilator flow below specification
Backup ventilator flow insufficient
Backup ventilator flow rate out of tolerance
Backup ventilator gas flow insufficient
Backup ventilator I time incorrect
Backup ventilator I time out of specification
Backup Ventilator Inspiratory Time out of specification
Backup ventilator inspiratory time out of tolerance
Backup Ventilator Manual Trigger not responding
Backup Ventilator PIP Relief not functioning correctly
Backup ventilator PIP relief out of tolerance
Backup ventilator rate incorrect
Backup ventilator rate out of specification
Backup ventilator rate out of tolerance
Battery charging voltage out of specification
Battery Fail alarm does not trigger
Battery Fail condition not triggering or delayed
Battery low alarm threshold out of tolerance
Battery low shutdown threshold out of tolerance
Battery voltage out of acceptable range
Battery voltage out of range
Battery voltage out of specification
Battery voltage out of tolerance
Calibration abort alarm triggered
Calibration: Airway pressure baseline
Calibration: LCD CAL mode verification
Calibration: Manual breath control
Calibration: Mode control and LCD verification
Calibration: Mode control and system response
Calibration: Mode verification
Calibration: Real Time Clock Reset
Calibration: Unit calibration
Cancel alarm function does not stop audible alarm
Cancel button does not clear External Power Fail alarm
Cancel button does not stop External Power Fail alarm
Cancel External Power Fail alarm
Cancel function does not clear External Power Fail alarm
Charge LED does not light
Charge LED indicator setup and operation
Charger voltage measurement
Charger voltage out of range at battery connector
Charger voltage out of specification
Charger voltage out of tolerance
Charger voltage output
Charger voltage output incorrect
Charger voltage output out of specification
Comp alarm does not occur
Comp alarm does not occur during compressor failure test
Comp alarm does not occur during compressor switching test
Comp alarm does not occur with external air and compressor switching
Comp alarm generation during external air to compressor switching
Comp alarm occurrence during external air switching
Comp alarm occurs
Comp alarm occurs during compressor operation
Compressor alarm occurs unexpectedly
Compressor fails to attempt start after external air button press
Compressor fails to start
CPAP apnea trigger time out of tolerance
CPAP backup rate out of tolerance
CPAP flow rate out of tolerance
CPAP inspiratory time out of tolerance
CPAP PIP relief pressure out of tolerance
Disconnect alarm does not deactivate after condition is fixed
Disconnect alarm on patient circuit removal
Excessive airway pressure during startup
Excessive negative airway pressure not detected
Exhaust valve opens and stays open
External Power Fail alarm cancel function
External Power Fail alarm cannot be canceled
External Power Fail alarm does not cancel
External Power Fail alarm does not cancel after Mute/Cancel pressed
External Power Fail alarm does not cancel properly
External Power Fail alarm does not clear when external power restored
External Power Fail alarm does not occur
External Power Fail alarm does not occur when top fuse removed
External Power Fail alarm occurs when top fuse removed
External power fail shutdown threshold out of tolerance
External Power Low alarm does not occur at expected voltage
External Power Low alarm does not trigger
External power low alarm does not trigger at correct voltage
External Power Low alarm does not trigger at expected voltage
External Power Low alarm does not trigger at threshold voltage
External Power Low alarm not displayed
External power low alarm not triggered at correct voltage
External power low alarm occurs
External Power Low alarm occurs at incorrect voltage
External power low alarm threshold
External power low alarm threshold out of tolerance
Failure Code 1 occurred
Failure Code 2 (No Gas, Comp) alarm not generated
Failure Code 2 displayed
Failure Code 2 displayed (No Gas, COMP alarm)
Failure Code 2 displays (No Gas, COMP alarm)
Failure Code 2 triggered
Failure Code 2: No Gas (COMP alarm)
Failure Code 2: No gas alarm (COMP)
Failure Code 3
Failure Code 3 (Excessive Airway Pressure)
Failure Code 3 alarm
Failure Code 3 displayed
Failure Code 3 occurred
Failure Code 3 occurs (Excessive Airway Pressure at startup)
Failure Code 4
Failure Code 4 (Memory Check Failure)
Failure Code 4 alarm
Failure Code 4 displayed
Failure Code 4 occurred
Failure Code 4 occurs (Memory check fails)
Failure Code 5 (Airway Pressure Threshold Exceeded)
Failure Code 5 (Exhaust Valve Failure) triggered
Failure Code 5 alarm (Exhaust Valve Failure)
Failure Code 5 alarm appears
Failure Code 5 alarm on high airway pressure
Failure Code 5 alarm with safety shutdown
Failure Code 5 displayed
Failure Code 5 occurs (Airway pressure exceeds 40 cmH2O for 4 seconds)
Failure Code 5 triggered (Exhaust Valve Failure)
Failure Code 5 triggered with safety shutdown
Failure Code 5 with safety shutdown
Failure Code 5: Excessive airway pressure shutdown
Failure Code 6 (Excessive Negative Pressure) triggered
Failure Code 6 alarm appears
Failure Code 6 alarm on excessive negative pressure
Failure Code 6 displayed
Failure Code 6 triggered (Excessive Negative Pressure)
FIO2 alarm does not occur with low oxygen pressure
FIO2 alarm during low oxygen tank pressure
FIO2 alarm occurs
FIO2 alarm occurs at low oxygen pressure
FIO2 alarm occurs at low oxygen pressure with high concentration setting
FIO2 alarm occurs at low oxygen tank pressure
FIO2 alarm occurs during low oxygen supply
FIO2 alarm triggers at low oxygen pressure
FiO2 reading out of tolerance
Inspiratory time out of tolerance (range verification)
Inspiratory/exhalation indicator malfunction
LCD indicator does not read OFF after external air button press
LCD screen does not blank when both fuses removed
Low Battery Alarm
Low battery alarm condition
Low Battery Alarm does not occur at expected voltage
Low Battery Alarm does not trigger
Low battery alarm not activating at correct voltage
Low Battery Alarm occurs at incorrect voltage threshold
Low battery alarm threshold incorrect
Low Battery Alarm triggered
Low Battery Alarm triggers at incorrect voltage
Manual Breath button activates during inhalation or exhalation
Manual Breath button does not function
Manual Breath button does not generate breath
Manual Breath button does not generate controlled breath
Manual breath button during expiratory pause
Manual Breath button generates unwanted breath during inhalation or exhalation
Manual Breath button held during inhalation does not function until baseline pressure
Manual Breath button held during inhalation produces no effect until current breath completes
Manual breath button hold during inhalation
Manual breath button inoperative
Manual breath button press during inhalation or exhalation
Manual Breath button produces no audible beep
Manual Breath button produces no effect during inhalation or exhalation
Manual Breath control does not generate controlled breath
Manual Breath control does not produce audible beep
Manual Breath control generates breath at wrong time in cycle
Manual Breath during held inhalation produces no beep after breath ends
Manual Breath function does not generate audible beep
Manual Breath function does not respond
Manual Breath generates audible beep
Manual Breath generates unwanted breath during inhalation or exhalation
Manual breath not triggered
Manual Breath push-button control verification
Manual Trigger does not deliver gas flow
Manual trigger does not function
Manual trigger does not stop gas flow at pressure limit
Manual trigger not functioning in backup ventilator
Mode control switch to A/C
Mode control switch to CPAP
Mode control switch to OFF
Mode control switch to SIMV
Multiple alarms display priority with newest first
Mute button does not silence audible alarm for 30 seconds
Mute/Cancel button does not mute alarm
Mute/Cancel button does not silence alarm
Mute/Cancel button does not silence alarm LED and audible alarm
Mute/Cancel button mutes alarm for 30 seconds
Mute/Cancel does not silence alarm LED and audible tone
Mute/Cancel function does not silence alarm
Mute/Cancel function does not stop audible alarm
No Gas (Comp) alarm - Failure Code 2
No Gas alarm (Failure Code 2)
O2 Low/Fail alarm does not occur at low oxygen pressure
O2 Low/Fail alarm does not occur at low tank pressure
O2 Low/Fail alarm during low oxygen tank pressure
O2 Low/Fail alarm occurs
O2 Low/Fail alarm occurs at low oxygen pressure
O2 Low/Fail alarm occurs at low oxygen tank pressure
O2 Low/Fail alarm occurs at low tank pressure
O2 Low/Fail alarm triggers at low tank pressure
Oxygen tank pressure below threshold
Peak airway pressure display malfunction
PEEP value out of tolerance
PIC line 1 does not display CHK EXT FUSE after Mute pressed
PIP relief does not occur at correct pressure
PIP relief not occurring at correct pressure
Positive inspiratory pressure relief setting out of specification
Rate out of tolerance (A/C and SIMV modes)
Rate out of tolerance (range verification)
Rate, Inspiration Time, and Tidal Volume controls non-functional in CPAP mode
Real time clock reset procedure
RTC battery voltage low
Safety shutdown does not occur at excessive airway pressure
Safety shutdown not activating at pressure threshold
Safety shutdown triggered by excessive airway pressure
Safety shutdown with sustained high airway pressure
Software version verification failure
Spontaneous flow rate out of tolerance (SIMV/CPAP)
System does not shut down at low external power voltage
System does not shut down at low external voltage
System fail LED comes on
System Failure LED and alarm when both fuses removed
System Failure LED does not activate when both fuses removed
System failure LED does not come on continuously
System failure LED does not illuminate
System Failure LED does not illuminate when bottom fuse removed
System Failure LED illuminated solid
System Failure LED indicator not working
System shutdown does not occur at expected voltage
System shutdown during battery low voltage test
System shutdown during low external power
System shutdown occurs at incorrect external power voltage
System shutdown occurs at low external voltage
System shuts down at low battery voltage
System shuts down at low external power voltage
Tidal volume alarm at 1150 ml setting
Tidal volume alarm cancellation at reduced setting
Tidal volume alarm occurs when set above 1050 ml
Tidal Volume control inoperative
Tidal volume not maintained at low oxygen pressure
Tidal volume not maintained during low oxygen pressure
Tidal volume out of tolerance
Tidal volume setting exceeds alarm threshold
Total Flow Backup alarm does not occur during outlet occlusion test
Total Flow Backup alarm does not occur with compressor inlet occlusion
Total Flow Backup alarm does not occur with restricted flow
Total Flow Backup alarm during low compressor inlet pressure
Total Flow Backup alarm generation
Total Flow Backup alarm occurs
Unit does not give Failure Code 2 alarm
Unit does not shut down after gas supply loss
Unit does not shut down at +100 cmH2O airway pressure
Unit does not shut down at excessive negative airway pressure
Unit does not shut down at excessive negative pressure
Unit does not shut down at expected voltage
Unit does not shut down at external power low
Unit does not shut down at low battery voltage
Unit does not shut down when both fuses removed
Unit shuts down after airway pressure decreases to -10 cmH2O
Unit shuts down after airway pressure reaches +100 cmH2O
Unit shuts down with Failure Code 2 alarm
Unit shuts down with Failure Code 5 alarm
Unit shuts down with Failure Code 6 alarm
Vt alarm does not occur or LED does not reactivate at elevated tidal volume
Vt alarm does not occur when Vt increased to 1150 ml
Vt alarm occurs
Vt alarm occurs above 1150 ml
Vt alarm occurs at 1150 ml setting
Vt alarm occurs at 1150 ml with LED and audible active
Vt alarm occurs at high tidal volume setting
Vt alarm occurs at very high tidal volume
Vt alarm occurs when set above 1150 ml
Vt alarm occurs when tidal volume exceeds 1150 ml
Vt alarm occurs when tidal volume exceeds critical threshold
Vt alarm occurs when tidal volume exceeds high threshold
Vt alarm occurs when tidal volume exceeds limit
Vt alarm occurs when tidal volume setting is increased further
Vt Settings alarm does not occur at 1050 ml
Vt Settings alarm does not occur when tidal volume exceeds threshold
Vt Settings alarm occurs
Vt Settings alarm occurs above 1050 ml
Vt Settings alarm occurs at 1050 ml
Vt Settings alarm occurs at 1050 ml setting
Vt Settings alarm occurs at high tidal volume
Vt Settings alarm occurs when tidal volume exceeds 1050 ml
Vt Settings alarm occurs when tidal volume exceeds limit
Vt Settings alarm should occur

287 more symptoms with ranked causes and checks are in ServiceForge. Connect ServiceForge to your AI

Error codes

Code	Meaning	Trigger	Severity
`1`	Transducer Cal Fail	Transducer calibration failure detected during startup or operation	error
`1 (Transducer Cal Fail)`	Transducer calibration failed during power-up self-test	Unit power-up or software calibration attempted	error
`2`	No Gas, Comp	No gas supply detected to compressor or gas supply line disconnected	critical
`2 (No Gas, Comp)`	No gas supply to compressor or compressor failure	Gas supply lost during operation	critical
`3`	Total Flow Backup / Excessive Airway Pressure	Flow cannot be delivered or airway pressure exceeds safe limits	critical
`3 (Total Flow Backup) / (Excessive Airway Pressure)`	Ver1.83X: Total Flow Backup triggered; Ver1.85X: Excessive airway pressure detected	Flow exceeds limits or pressure exceeds safety threshold	error
`4`	Excessive Airway Pressure / Memory Check	Airway pressure exceeds 40 cmH2O or memory integrity failure	error
`4 (Excessive Airway Pressure) / (Memory Check)`	Ver1.83X: Excessive airway pressure; Ver1.85X: Memory (EEPROM) check failed	Pressure exceeds safety limit or EEPROM integrity check failed	error
`5`	Memory check failure or exhalation valve failure	Internal memory test fails or exhalation valve malfunction detected	error
`5 (Memory Check) / (Exhalation Valve Failure)`	Ver1.83X: Memory check failed; Ver1.85X: Exhalation valve does not open properly	EEPROM error or exhalation valve malfunction	error
`6`	Exhaust Valve Fail / Excessive Negative Pressure	Exhaust valve failure or excessive negative pressure in circuit	error
`6 (Exhaust Valve Fail) / (Excessive Negative Pressure)`	Ver1.83X: Exhaust valve failure; Ver1.85X: Negative pressure exceeds safe level	Exhaust valve malfunction or patient breathing generates excessive negative pressure	error
`7`	Excessive Negative Pressure / Run-Time Cal Fail	Negative pressure exceeds limits or runtime calibration fails	error
`7 (Excessive Negative Pressure) / (Run-Time Cal Fail)`	Ver1.83X: Excessive negative pressure; Ver1.85X: Run-time calibration failed	Negative pressure spike or runtime calibration procedure failure	error
`Audible alarm 4-5 pulse`	Repeating 4 to 5 pulse alarm indicating system status	Audible alarm gives a repeating 4 to 5 pulse alarm	warning
`Audible alarm 4-5 pulse`	System failure alarm	System failure condition detected	critical
`BATTERY LOW/FAIL`	Battery voltage is critically low or battery has failed	Battery voltage drops below acceptable threshold or battery is disconnected	warning
`BATTERY LOW/FAIL`	Low battery voltage detected; unit operating on battery below safe voltage threshold.	Battery voltage falls to 11.1V - 11.7V range.	warning
`BATTERY LOW/FAIL`	Low battery condition detected	Battery voltage drops below 11.1V - 11.7V range	warning
`Calibration Abort Alarm`	Calibration was interrupted or not completed successfully	Mode control switched away from CAL mode before calibration completes	warning
`CHK EXT FUSE`	Check external power supply fuse	Displayed on PIC line 1 after External Power Fail alarm and Mute/Cancel press	warning
`Code 1`	Transducer calibration failure (firmware version 1.83X) or Transducer Cal Fail	Pressure transducer returns invalid or out-of-range values during sensor diagnostics; cannot be calibrated to expected values	error
`Code 2`	No gas or compressor failure (applicable to both firmware versions 1.83X and 1.85X)	Unit detects no gas supply pressure or compressor output failure during system initialization or operation	critical
`Code 3`	Total flow backup failure or Excessive airway pressure (varies by version: backup in 1.83X, pressure in 1.85X)	Version 1.83X: Total flow measurement circuit detects excessive or unmeasurable flow during backup mode. Version 1.85X: Airway pressure exceeds safety threshold (typically 50+ cmH2O) outside normal range.	error
`Code 4`	Excessive airway pressure (firmware version 1.83X) or Memory check failure (firmware version 1.85X)	Version 1.83X: Airway pressure exceeds safe limit (typically 50+ cmH2O) outside normal breath delivery window. Version 1.85X: EEPROM memory checksum or data integrity error detected during boot or operation.	error
`Code 5`	Memory check failure (firmware version 1.83X) or Exhalation valve failure (firmware version 1.85X)	Version 1.83X: EEPROM checksum or RAM integrity error detected. Version 1.85X: Exhalation valve does not open or close properly; stuck closed or mechanical binding detected.	error
`Code 6`	Exhaust valve failure (firmware version 1.83X) or Excessive negative pressure (firmware version 1.85X)	Version 1.83X: Exhaust valve does not vent during safety shutdown or pressure relief cycles; may not open when commanded. Version 1.85X: Inspiratory effort (negative airway pressure) exceeds safety limit during spontaneous or demand breathing (typically < -25 cmH2O).	warning
`Code 7`	Excessive negative pressure (firmware version 1.83X) or Run-time calibration failure (firmware version 1.85X)	Version 1.83X: Inspiratory effort (negative airway pressure) exceeds safe limit during spontaneous or demand breathing (<-25 cmH2O typical). Version 1.85X: On-device automatic calibration routine fails to converge or produce valid calibration values.	warning
`Comp`	Compressor alarm	Compressor fails to start or external air pressure drops below threshold during operation	warning
`Comp alarm`	Compressor alarm indicating compressor failure or inability to start	Switching from external air to compressor operation; external gas pressure below 35 PSI +/- 2 PSI	error
`Comp alarm`	Compressor alarm	Compressor fails to start or cannot maintain operation when External Air is toggled off	warning
`Comp alarm`	Compressor failure alarm indicating compressor cannot supply sufficient gas pressure	Compressor fails to provide adequate pressure during operation; external air valves take over gas supply during Comp alarm condition	warning
`Comp Alarm (Failure Code 2)`	Compressor failure with No Gas condition	External gas pressure drops below 35 PSI +/- 2 PSI during compressor operation	error
`Disconnect`	Patient circuit has become disconnected from the ventilator	Patient circuit is removed from test lung and next breath is fired with no positive airway pressure rise sensed	critical
`Disconnect`	Disconnection detection alarm	Patient circuit becomes disconnected from ventilator outlet	warning
`Disconnect alarm`	Alarm indicating loss of patient circuit connection or gas delivery path interruption	During external air and compressor switching test or when circuit is disconnected	warning
`Disconnect alarm`	Circuit or patient disconnection detected	Hose circuit disconnected from test lung or patient	warning
`Disconnect alarm`	Disconnect alarm	Loss of gas delivery or patient disconnect detected	warning
`Disconnect alarm`	Patient circuit or breathing hose disconnected from patient or ventilator	Loss of airway pressure or circuit continuity	error
`External Power Fail`	External power supply has failed or been interrupted	Top fuse is removed while in AC mode with battery connected	warning
`External Power Fail`	Loss or failure of external power supply	Top fuse is removed or external power supply is disconnected while in A/C mode with both external power and battery connected	warning
`External Power Fail alarm`	External electrical power disconnected or lost	External AC power supply unplugged or power loss	critical
`EXTERNAL POWER LOW`	External power supply voltage has dropped below safe operating threshold	External power voltage drops below 10.5V - 11.1V range	warning
`Failure Code 1`	Self Check failure during startup	Self-check fails when unit powers on	critical
`Failure Code 2`	No Gas, COMP	Self Check fails during startup or gas supply is disconnected	error
`Failure Code 2`	No Gas, Comp alarm - external gas supply failure during compressor operation	External gas pressure drops below 35 PSI when compressor is active	critical
`Failure Code 2 (No Gas, Comp)`	No gas available to compressor; backup to external air activated	External gas supply pressure falls below 35 PSI +/- 2 PSI during compressor operation attempt	error
`Failure Code 3`	Excessive airway pressure	Airway pressure exceeds safe limits during startup	critical
`Failure Code 4`	Memory self-check failure	Memory integrity check fails during startup	critical
`Failure Code 5`	Safety shutdown triggered due to excessive airway pressure exceeding 40 cmH2O for 4 seconds	Airway pressure sustained above 40 cmH2O for 4 seconds or more	critical
`Failure Code 5`	Excessive airway pressure above 40 cmH2O with safety shutdown	Airway pressure rises above 40 cmH2O and remains there for 4 seconds or more	critical
`Failure Code 5`	Ventilator Failure Code 5	Pressure exceeds 40 cmH2O for 4 seconds	critical
`Failure Code 5`	Exhaust Valve Failure	Airway pressure reaches +100 cmH2O or above	error
`Failure Code 5`	Safety shutdown activated	Airway pressure exceeds 40 cmH2O for 4 seconds	critical
`Failure Code 6`	Excessive Negative Pressure	Airway pressure falls to -10 cmH2O or below	error
`Failure Code 7`	Run-Time Transducer Calibration Failure	Transducer calibration fails during operation	error
`FIO2`	Oxygen concentration setting cannot be maintained due to low oxygen supply pressure	FIO2 setting at 60% or higher with oxygen tank pressure below 35 PSI +/- 2 PSI	critical
`FIO2`	Fraction of inspired oxygen alarm; oxygen delivery out of specification	Oxygen tank pressure drops below 35 PSI +/- 2 PSI when high FIO2 set	critical
`FIO2`	Oxygen concentration delivery failure	Oxygen tank pressure insufficient to achieve set FIO2; pressure below 45 PSI at high concentration settings	critical
`FIO2`	FIO2 (inspired oxygen fraction) sensor detects insufficient oxygen	Oxygen tank pressure below threshold while FIO2 is set above 21%	warning
`O2 Low/Fail`	Oxygen tank pressure too low or oxygen supply failed	Oxygen tank pressure drops below 45 PSI threshold at 60% FIO2	critical
`System failure`	System has shut down due to insufficient external power voltage	External power voltage drops below 9.50V - 10.50V range	critical
`System Failure`	Both external power and battery power lost or fuses removed	Top and bottom fuses both removed	critical
`System Failure`	Critical system failure detected	Bottom fuse is removed while top fuse is already removed	critical
`System Failure LED`	System failure condition detected	Internal system fault or critical component failure	critical
`Total Flow Backup`	Flow backup alarm - inadequate gas delivery detected	Delivered tidal volume falls below 50% of set tidal volume for 4-5 consecutive breaths	error
`Total Flow Backup`	Total flow backup alarm	Actual delivered tidal volume drops below 50% of set tidal volume for 4+ consecutive breaths	warning
`Total Flow Backup`	Alarm indicating insufficient flow delivery due to compressor inlet obstruction	Actual tidal volume less than half of set tidal volume for 4-5 consecutive breaths	warning
`Total Flow Backup Alarm`	Insufficient gas flow backup when primary flow path is compromised	Actual delivered tidal volume drops below 50% of set tidal volume for 4-5 breaths	warning
`Total Flow Backup alarm`	Actual delivered tidal volume insufficient	Actual tidal volume drops below half of set tidal volume after 4-5 breaths	warning
`Total Flow Backup alarm`	Tidal volume insufficient due to compressor inlet restriction	Actual delivered tidal volume falls below half of set tidal volume for 4-5 consecutive breaths	warning
`Total Flow Backup Alarm`	Alarm indicating total flow output is below expected tidal volume threshold	Compressor inlet occlusion or flow restriction reduces actual tidal volume to less than half of set tidal volume for 4-5 breaths	warning
`Vt`	Actual tidal volume delivered differs significantly from setting	Delivered tidal volume diverges from set value during ventilation	error
`Vt`	Tidal volume delivery is outside acceptable parameters	Tidal volume setting increased beyond alarm threshold (1150 ml or greater)	error
`Vt`	Measured or set tidal volume exceeds alarm limit	Tidal volume setting increased to 1150 ml	error
`Vt`	Measured tidal volume out of specification or range exceeded	Tidal volume setting set to 1150 ml or higher	error
`Vt`	Tidal volume critically high	Vt set to 1150 ml or higher	error
`Vt alarm`	Tidal Volume alarm	Actual delivered tidal volume deviates from set tidal volume	warning
`Vt alarm`	Tidal volume alarm indicating delivered tidal volume does not meet set value	During external air and compressor switching test or when delivery is insufficient	warning
`Vt Settings`	Tidal volume setting is outside configured parameters	Tidal volume setting changed to 1050 ml or greater	warning

Likely causes and actions for each code are in ServiceForge. Connect ServiceForge to your AI

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