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Manufacturer
Model
What This Guide Helps With
Flow sensor calibration failures, inaccurate readings, or alarms caused by external factors such as contamination, setup issues, or environmental conditions.
Step-by-Step Troubleshooting
Ensure Patient Safety First
- Remove the ventilator from active patient use if calibration is required
- Transition the patient to a backup ventilator
Expected: Patient ventilation continues safely
Why it matters: Calibration errors can lead to inaccurate tidal volume delivery
Verify the Reported Issue
- Attempt to run the flow sensor calibration per normal startup or service menu process
- Observe for failure to complete or error messages
- Check for inconsistent or drifting readings
Expected: Error is reproducible
Why it matters: Confirms a true calibration issue vs user workflow error
Check Circuit and Patient Setup (Most Common Cause)
- Disconnect and inspect the entire breathing circuit
- Remove patient circuit from ventilator
- Ensure no tubing is kinked or occluded
- Remove inline accessories (filters, HMEs, water traps)
Expected: Open, unobstructed circuit
Why it matters: Calibration requires an open system with no resistance
Inspect Flow Sensor and Connections
- Locate the flow sensor and inspect for proper seating and connection
- Check for visible damage or cracks
- Check for moisture or condensation
- Reseat the sensor securely
Expected: Sensor is clean, dry, and properly connected
Why it matters: Poor connection or contamination directly affects calibration
Check for Moisture or Contamination (Very Common)
- Inspect for condensation inside tubing or sensor
- Check for secretions or debris
- Replace disposable components if contaminated
- Allow reusable sensor to dry if needed
Expected: Dry, clean airflow path
Why it matters: Moisture alters airflow measurement and causes calibration failure
Ensure Proper Calibration Conditions
- Ensure ventilator is not connected to a patient
- Ensure circuit is disconnected or properly configured for calibration
- Place ventilator in a stable environment without airflow drafts
Expected: Calibration runs without interference
Why it matters: External airflow or resistance will cause failure
Power Cycle the Ventilator
- Turn the unit off
- Wait 30 seconds
- Power back on and retry calibration
Expected: Calibration completes successfully
Why it matters: Clears temporary software or sensor communication issues
Verify Use of Correct Accessories
- Ensure only compatible circuits and sensors are used for the HT70 Plus
Expected: Compatible components installed
Why it matters: Non-approved accessories can cause inaccurate flow readings
Attempt Calibration with Known Good Setup
- Swap in a known good flow sensor if available
- Use a known good circuit
Expected: Calibration passes with known good components
Why it matters: Helps isolate whether issue is accessory vs device
If the Problem Persists
If calibration continues to fail after verifying circuit, sensor condition, and setup, the issue is likely internal (flow sensor module, internal pneumatics, or control board).
Remove the ventilator from service, label it Out of Service, and send for repair or bench evaluation.
Clinical Use Tip
Never attempt flow calibration while connected to a patient. Always transition the patient to another ventilator before troubleshooting to ensure therapy continuity.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Ventilator displaying flow sensor calibration error and failing calibration."
Cause
What was observed during troubleshooting.
Example:
"Moisture found in flow sensor and circuit causing inaccurate readings."
Resolution
What action was taken.
Example:
"Replaced circuit and dried sensor; calibration completed successfully."
Helpful Details to Include (If Known)
- Calibration error message displayed
- Circuit condition (wet/dry, obstructed)
- Sensor condition and connection
- Accessories removed during testing
- Calibration success or failure after steps
- Final device status
Final Thought
Flow calibration issues are most often caused by external factors like moisture, circuit resistance, or setup errors. Always rule these out before assuming internal failure. Patient safety and proper escalation are critical, and clear documentation ensures accurate follow-up and trend tracking.
That is successful troubleshooting.