Ventilators · paraPAC plus family

Smiths Medical paraPAC plus 300: troubleshooting and error codes

The ServiceForge knowledge base holds 42 documented symptoms for the Smiths Medical paraPAC plus 300, with 45 ranked causes, 124 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

Back-pressure leak exceeds tolerance

Tidal volume difference between 5 and 25 cmH2O back-pressure greater than 10mL

Ranked causes

1. Patient circuit connection leak (common)
2. Bellows or internal seal failure (rare)

First check

Set back-pressure to 5 cmH2O and record tidal volume

Test point: Certifier tidal volume reading
Expected: Stable tidal volume reading

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

PEEP gauge readings exceed tolerance

Master gauge and paraPAC plus manometer readings differ by more than 2 cmH2O

Ranked causes

1. Gauge calibration error (occasional)
2. Exhalation diaphragm response delay (occasional)

First check

Set PEEP and stabilize reading

Test point: Master gauge and paraPAC plus manometer
Expected: Steady state reading after initial surge settles

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

Ventilator does not inhibit demand breaths patient safety

Ventilator continues automatic cycling instead of inhibiting during demand breath attempts; spontaneous breath LED does not illuminate

Ranked causes

1. Demand inhibit function failure or patient valve malfunction (common)
2. Patient valve blockage or contamination (occasional)

First check

Demand 3-4 adult breaths during expiratory phase

Test point: Patient valve inlet
Expected: Ventilator inhibits (no cycling during demand breaths); Spontaneous Breath LED illuminates

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

Alarm LEDs and audible alarm not illuminating or sounding patient safety

When function switch set to I CMV without gas supply, alarm LEDs do not illuminate in sequence or medium priority audible alarm does not sound within 1 minute.

Ranked causes

1. Alarm system electronics failure (rare)

First check

Verify gas supply disconnected

Test point: Gas supply connection
Expected: No gas connected to ventilator

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

Alarm silence button does not mute alarm

Pressing silence button fails to mute audible alarm for approximately 60 seconds

Ranked causes

1. Silence button circuit malfunction (unknown)

First check

Verify alarm silence duration

Test point: Audible alarm output
Expected: Alarm silenced for approximately 60 seconds

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

Alarm silence not functioning for 60 seconds patient safety

When silence button is pressed during active alarm, alarm does not silence or silence duration is not approximately 60 seconds.

Ranked causes

1. Silence button switch or timer circuit malfunction (rare)

First check

Press silence button once during active alarm

Test point: Silence button
Expected: Alarm mutes immediately

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

BPM and tidal volume incorrect at 100% oxygen patient safety

Frequency and tidal volume readings on TSI certifier do not match expected values during 100% O2 test

Ranked causes

1. Tidal volume or frequency control malfunction or incorrect setting (unknown)

First check

Measure BPM and tidal volume at 100% oxygen with specified back-pressure

Test point: TSI certifier measurement
Expected: BPM and tidal volume per Service Test Sheet requirements
Tools: TSI Certifier, back-pressure device (35 cmH2O)

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

Control knob re-alignment

Procedure to correct misalignment of control knob markers and end caps on Frequency, Tidal Volume, Function, O2 %, or Variable Relief controls.

Ranked causes

1. Control knob marker or end cap misalignment during operation or maintenance (occasional)

First check

Rotate knob fully counter-clockwise for re-alignment ease

Test point: Control knob
Expected: Knob rotates fully counter-clockwise

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

Cycle LED does not flash at expected pressure

During ICMV mode with increasing back pressure, cycle LED fails to flash between 8.5 and 11.5 cmH2O

Ranked causes

1. Test box configuration incorrect (common)

First check

Verify cycle LED flash during back pressure increase

Test point: Cycle LED indicator
Expected: LED begins to flash between 8.5 and 11.5 cmH2O

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

Cylinder key inspection high voltage

Visual inspection of cylinder key for cracks and damage to attachment cable to ensure integrity and safe operation.

Ranked causes

1. Cracking or cable damage to cylinder key requiring replacement (occasional)

First check

Inspect cylinder key for cracking

Test point: Cylinder key body
Expected: No visible cracks

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

Demand inhibit function not working patient safety

Ventilator fails to inhibit automatic cycling when patient demands breaths, or fails to recognize adequate breath triggers

Ranked causes

1. Demand valve or sensor malfunction (common)

First check

Demand 3-4 adult breaths in expiratory phase

Test point: Ventilator cycling and Spontaneous Breath LED
Expected: Ventilator inhibits cycling; Spontaneous Breath LED illuminates

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

Demand valve not functioning correctly patient safety

Difficult to breathe from patient circuit connection or manometer needle does not move as expected during spontaneous breath

Ranked causes

1. Demand valve obstruction or seal failure (occasional)

First check

Set function switch to O-DEMAND

Test point: Function Switch
Expected: O-DEMAND position

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

Demand valve not functioning in O DEMAND mode patient safety

Difficult to breathe from patient connection port or manometer needle does not move slightly right of zero, indicating demand valve malfunction.

Ranked causes

1. Demand valve obstruction or malfunction (unknown)

First check

Set function switch to O DEMAND

Test point: Function Switch
Expected: O DEMAND position

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

Disconnect alarm does not trigger within 10 seconds patient safety

Disconnect LED and audible alarm fail to sound when patient hose disconnected from ventilator outlet

Ranked causes

1. Alarm circuit malfunction (unknown)

First check

Measure disconnect alarm response time

Test point: Disconnect LED and alarm output
Expected: approximately 10 seconds

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

Disconnect alarm does not trigger within specified time patient safety

When patient hose is disconnected from ventilator outlet at specified back pressure, Disconnect LED does not flash or audible alarm does not sound within expected 10 seconds.

Ranked causes

1. Disconnect sensor or alarm circuit malfunction (rare)

First check

Set back pressure to 15 cmH2O with patient circuit connected

Test point: Back pressure device and patient hose
Expected: Back pressure at 15 cmH2O

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

Frequency or tidal volume reading incorrect (100% O2)

BPM, tidal volume, I:E ratio or inspiration time measurements do not meet specification during 100% oxygen test

Ranked causes

1. Ventilator timing or volume delivery malfunction (unknown)

First check

Measure frequency at maximum tidal volume (100% O2)

Test point: TSI certifier BPM reading
Expected: Within Service Test Sheet specification

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

Frequency or tidal volume reading incorrect (50% O2 Air-Mix)

BPM, tidal volume, I:E ratio or inspiration time measurements out of spec during air-mix 50% oxygen test

Ranked causes

1. Air-mix valve malfunction affecting delivery (unknown)

First check

Measure oxygen concentration at 1000mL tidal volume

Test point: Oxygen monitor reading
Expected: 41% to 61% with back-pressure ≈29 cmH2O, 41-61%

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

Function switch is leaking patient safety

Ventilator continues to cycle after function switch is turned off to DEMAND position

Ranked causes

1. Function switch internal leak or seal failure (common)

First check

Turn function switch from I-CMV to O-DEMAND

Test point: Function Switch
Expected: Ventilator should stop cycling immediately

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

Function switch leaking after power off patient safety

Ventilator continues to cycle after function switch has been switched to O DEMAND position, indicating gas leakage through switch.

Ranked causes

1. Function switch defective or leaking (rare)

First check

Switch to O DEMAND and monitor ventilator cycling

Test point: Function Switch O DEMAND position
Expected: Ventilator stops cycling immediately, all alarm lights and audible signals cease

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

Gas input hose inspection high voltage

Visual inspection of gas input hose for damage, internal integrity, delamination, and leaks; check date code for replacement schedule.

Ranked causes

1. Hose damage, delamination, internal degradation, or gas leaks requiring replacement (occasional)

First check

Check hose date code for replacement schedule

Test point: Hose label
Expected: Date code indicates hose less than 5 years old

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

Gas supply indicator not changing color

Gas supply indicator stays red and does not change to white when gas supply is connected and pressure is above minimum

Ranked causes

1. Gas supply indicator LED failure or pressure switch defect (rare)

First check

Connect gas supply and set input pressure

Test point: Input pressure gauge and gas supply indicator
Expected: Gas supply indicator changes from red to white at 60 psi or above

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

Gas supply indicator not changing from red to white

When cylinder valve opened or gas connected to wall supply, gas supply indicator does not change from red to white even when supply pressure above minimum specified.

Ranked causes

1. Gas supply indicator sensor or LED failure (rare)

First check

Verify function switch set to O DEMAND

Test point: Function Switch
Expected: O DEMAND position

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

High patient pressure alarm does not activate patient safety

High pressure LED and alarm fail to operate when back pressure device fully closed

Ranked causes

1. High pressure alarm circuit malfunction (unknown)

First check

Verify high pressure alarm activation

Test point: High pressure LED and alarm output
Expected: LED and alarm activate immediately when back pressure fully closed

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

High patient pressure alarm not triggering patient safety

When back pressure device is fully closed to increase patient pressure, high pressure LED and alarm do not illuminate or sound immediately.

Ranked causes

1. High pressure sensor or alarm circuit malfunction (rare)

First check

Reconnect patient circuit and back pressure device from previous test

Test point: Patient circuit outlet and back pressure device
Expected: Patient circuit properly connected with back pressure device

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

Internal leak in ventilator circuit patient safety

Pressure drops excessively when ventilator is locked off and pressurized

Ranked causes

1. Internal seal or connection failure (occasional)

First check

Set function switch to O-DEMAND

Test point: Function Switch
Expected: O-DEMAND position

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

Internal pressure leak detected

Inlet pressure gauge drops more than one small division during lock-off test, indicating internal gas leak in ventilator.

Ranked causes

1. Internal gas leak in ventilator (unknown)

First check

Set ventilator to O DEMAND

Test point: Function Switch
Expected: O DEMAND position

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

Low battery alarm not functioning with test battery

When standard 1.5V AA test battery is installed and function switch set to I CMV, low battery light does not flash during startup routine.

Ranked causes

1. Low battery sensor or LED circuit malfunction (rare)

First check

Remove original battery and insert standard 1.5V AA test battery

Test point: Battery compartment
Expected: New 1.5V AA battery installed (must be new, not discharged)

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

Low battery indicator not functioning

Low battery LED does not flash when low-capacity battery is installed and I-CMV mode is selected

Ranked causes

1. Low battery detection circuit failure (rare)

First check

Install standard 1.5V AA test battery

Test point: Battery compartment
Expected: 1.5V AA size battery installed

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

Manometer reading exceeds tolerance during pressure test patient safety

Master gauge and paraPAC plus manometer readings differ by more than 2 cmH2O during steady-state ventilation

Ranked causes

1. Manometer mechanism inertia or exhalation diaphragm response lag (common)

First check

Measure pressure with calibrated low pressure gauge (0-80 cmH2O range)

Test point: Between end of patient circuit and test lung
Expected: Steady-state reading within 2 cmH2O of master gauge, ±2 cmH2O
Tools: Calibrated low pressure gauge, master gauge, paraPAC plus manometer

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

Manual breath function limited or not working patient safety

Gas does not flow from patient connection port when manual breath button is depressed, or flow is not appropriate for frequency and tidal volume control settings.

Ranked causes

1. Manual breath button or internal mechanism malfunction (unknown)

First check

Set function switch to O DEMAND

Test point: Function Switch
Expected: O DEMAND position

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

Manual breath function not working patient safety

Depressing manual breath button does not produce gas flow or flow is not limited correctly by frequency and tidal volume controls

Ranked causes

1. Manual breath button mechanism failure or control linkage defect (rare)

First check

Set function switch to O-DEMAND and depress manual breath button

Test point: Manual breath button in center of function switch
Expected: Gas flows from patient connection port while button depressed

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

O2 therapy/CPAP output does not match specified flow patient safety

TSI certifier reading differs from expected oxygen flow or CPAP output

Ranked causes

1. Incorrect oxygen flow setting or valve malfunction (unknown)

First check

Measure oxygen flow rate from oxygen therapy/CPAP connector

Test point: Oxygen flow/CPAP connector to TSI certifier
Expected: Flow rate as specified in Service Test Sheet SLPM
Tools: TSI certifier, Oxygen Therapy Test Hose (500-85868)

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

O2 therapy/CPAP output flows out of tolerance

Measured flow rates from TSI certifier do not match specified tolerances during O2 therapy or CPAP testing

Ranked causes

1. Flow control valve malfunction (unknown)

First check

Measure O2 therapy/CPAP output flow

Test point: TSI flow meter reading
Expected: Within specified tolerances from Service Test Sheet

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

Oxygen concentration out of range during air-mix test patient safety

Oxygen concentration measurement at patient outlet does not fall within specified range during air-mix (50% O2) operation

Ranked causes

1. Air-mix valve malfunction or incorrect oxygen ratio setting (unknown)

First check

Measure oxygen concentration at 1000 mL tidal volume air-mix setting

Test point: Oxygen monitor at TSI certifier outlet
Expected: 41% to 61%, 41% to 61%
Tools: Oxygen Monitor (W7038), calibrated within 8 hours

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

ParaPAC plus ventilator visual inspection patient safety

Visual inspection of ventilator case, fittings, gauge, control knobs, labels, manometer connection, input/output connectors, sintered filter, and battery hatch for damage and proper function.

Ranked causes

1. Damaged ventilator components, loose connectors, obstructed filter, or worn control knobs requiring repair or replacement (occasional)

First check

Inspect ventilator case and fittings for damage

Test point: Case, gas input/output fittings, gauge, supply indicator, control knobs, labels
Expected: No visible damage; all fittings intact

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

Patient circuit inspection patient safety

Visual inspection of patient circuit hose for damage, splits, and holes; inspection of Patient Valve assembly for cracks and scoring. Check expiration date if test circuit.

Ranked causes

1. Patient circuit damage (splits, holes, cracks, scoring) or expiration requiring replacement (occasional)

First check

Check corrugated tube for damage

Test point: Patient circuit corrugated hose
Expected: No damage, splits, or small holes

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

Patient pressure cycling check failure patient safety

When increasing back pressure on connected patient circuit, cycle LED does not begin to flash or flashes outside specified pressure range.

Ranked causes

1. Pressure sensor or cycle detection circuit malfunction (rare)

First check

Connect patient circuit with back pressure device and calibrated pressure gauge

Test point: Ventilator outlet and patient circuit
Expected: Patient circuit connected and back pressure device installed

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

Regulator assembly inspection and maintenance high voltage

Visual inspection of cylinder regulator, T-handle, pin-index yoke, filter, outlet connector, gauge, relief valves, and Constant Flow Selector Head to ensure proper function and safety.

Ranked causes

1. Damaged or loose regulator components requiring replacement or repair (occasional)

First check

Inspect T-handle condition

Test point: T-handle
Expected: Straight, undamaged, screws in and out freely

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

Relief valve does not open at specified pressure patient safety

Back-pressure device reading does not match expected VRV relief pressure setting during pressure test

Ranked causes

1. Relief valve malfunction or incorrect setting (unknown)

First check

Measure relief valve opening pressure

Test point: Back-pressure device connected to calibrated 0-100 cmH2O gauge
Expected: Pressure as specified in Service Test Sheet cmH2O
Tools: Calibrated pressure gauge (0-100 cmH2O), back-pressure device

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

Spontaneous breathing function not working patient safety

Spontaneous breathing valve fails to open to atmosphere when gas supply falls below 40 psi minimum input pressure

Ranked causes

1. Spontaneous breathing valve stuck or blocked (occasional)

First check

Set Output Valve (B) to LOCK; demand breaths until supply depleted

Test point: Breathing resistance and valve opening
Expected: Spontaneous breathing valve opens; slight increase in breathing resistance from atmosphere

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

Spontaneous breathing valve does not open when supply depleted patient safety

Breathing resistance does not ease when gas supply falls below minimum pressure; spontaneous breathing valve fails to open to atmosphere

Ranked causes

1. Spontaneous breathing valve malfunction or obstruction (common)

First check

Monitor breathing resistance while demanding breaths as supply pressure drops

Test point: Patient breathing circuit and valve
Expected: Slight increase in breathing resistance after spontaneous breathing valve opens

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

Ventilator does not cycle continuously patient safety

When function switch is turned on, ventilator does not provide continuous cycle of breaths or pauses between breaths occur

Ranked causes

1. Input manifold timer valve defect or blockage (unknown)

First check

Verify function switch set to DEMAND position

Test point: Function Switch
Expected: DEMAND

3 more checks with pass and fail actions, 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.