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What This Guide Helps With
This guide addresses the alarm FLOW SENSOR CAL DUE ! indicating that flow sensor calibration is overdue or was reset. This condition can lead to inaccurate flow and volume readings, potentially impacting ventilation reliability and patient safety.
Step-by-Step Troubleshooting
Ensure Patient Safety First
- Remove the machine from active patient use or transition to another anesthesia machine
- Ensure patient ventilation is maintained on a safe, alternate device
- Do not perform calibration while connected to a patient
Verify the Reported Alarm and Behavior
- Power on the unit and confirm the FLOW SENSOR CAL DUE ! alarm is present
- Check if the alarm appears at startup
- Determine if the alarm followed a cable reconnection
- Observe if flow/volume readings are present but potentially inaccurate
Check Flow Sensor Cable Connection
- Inspect the flow sensor cable at both ends
- Ensure connectors are fully seated
- Look for bent pins or physical damage
- Reseat the cable securely
Inspect Flow Sensor and Breathing Circuit
- Check for moisture or condensation in the flow sensor
- Inspect for debris or contamination
- Verify proper installation of the sensor
- Confirm breathing circuit integrity
Perform Flow Sensor Calibration
- Place the machine in standby mode
- Ensure no patient is connected
- Follow on-screen prompts to complete calibration
- Allow the process to finish without interruption
Confirm Alarm Clears and Function Restores
- Verify the alarm is no longer displayed
- Confirm normal flow and volume readings
- Observe stable operation during testing
If Alarm Persists After Calibration
- Repeat the calibration procedure
- Try a known-good flow sensor if available
- Recheck cable connections and condition
- Assess for possible internal sensor or circuit issue
If the Problem Persists
If external causes have been ruled out and calibration cannot be completed or the alarm continues:
- Remove the device from service
- Label the unit as Out of Service
- Send for repair or bench evaluation
Clinical Use Tip
Never troubleshoot or calibrate the flow sensor on an active patient. Always transition the patient to a backup device and perform calibration in standby mode to ensure accuracy and safety.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Unit displayed FLOW SENSOR CAL DUE ! alarm."
Cause
What was observed during troubleshooting.
Example:
"Flow sensor required calibration due to elapsed interval or cable reconnection."
Resolution
What action was taken.
Example:
"Verified connections, performed flow sensor calibration successfully, alarm cleared, and unit returned to service."
Helpful Details to Include (If Known)
- Alarm behavior
- Accessories swapped
- Power behavior
- Environmental factors
- Indicator lights
- Final device status
Final Thought
Calibration-related alarms are not failures, but they must be addressed promptly. Accurate flow measurements are critical for safe ventilation. Completing calibration and escalating when necessary ensures reliable operation and patient safety.
That is successful troubleshooting.