On this page
Asset Type
Manufacturer
Model
What This Guide Helps With
This guide assists Clinical Engineering in troubleshooting internal fan or temperature-related fault alarms on the Nellcor PM1000N. These alarms may indicate overheating, fan malfunction, or airflow obstruction. Most often, external factors such as blocked vents, environmental heat, or power issues are involved before internal failure occurs.
Step-by-Step Troubleshooting
Ensure Patient Safety
- Move the patient to another functioning monitor if the unit is currently in use.
- Do not attempt troubleshooting on a patient-connected device to prevent inaccurate readings or alarm mismanagement.
Check Environmental Conditions
- Confirm the unit is not exposed to direct sunlight or heat sources.
- Ensure ambient temperature is within the manufacturer-specified operating range.
- High room temperatures or nearby heat sources can trigger thermal alarms.
Inspect Ventilation and Placement
- Check that all air vents are unobstructed and free of dust or debris.
- Make sure the device is on a stable, flat surface that allows airflow.
- Avoid placing the unit in confined spaces or against walls.
Examine AC Power and Battery Status
- Verify the AC power supply is stable and providing proper voltage.
- Confirm the backup battery is charged and seated correctly.
- Power fluctuations can cause temperature monitoring errors.
Perform a Soft Reset
- Power cycle the unit using the correct shutdown procedure.
- Some transient fan or thermal faults may clear after a proper restart.
Observe Alarm Behavior
- Note if the alarm persists immediately after power-up or only after prolonged use.
- Continuous alarms after environmental and power checks indicate internal issues.
If the Problem Persists
External and environmental causes have likely been ruled out. The internal fan or temperature sensor may be failing.
Action:
- Remove the unit from service.
- Label as Out of Service.
- Send for repair or bench evaluation per manufacturer guidelines.
- Clinical Engineering should avoid internal disassembly; this is beyond routine troubleshooting.
Clinical Use Tip
- Never attempt to override temperature alarms while monitoring a patient.
- Always provide an alternative pulse oximeter to maintain continuous SpO₂ monitoring.
- Document environmental observations in the work order to assist repair.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
“Internal fan alarm displayed; unit overheating alarm triggered intermittently during use.”
Cause
What was observed during troubleshooting.
Example:
Observed vents partially blocked and unit operating in high ambient temperature. Alarm persisted after environmental correction.
Resolution
What action was taken.
Example:
Unit removed from service, labeled Out of Service, and sent for manufacturer repair evaluation.
Helpful Details to Include
- Room temperature at time of alarm
- Device placement (vent clearance, airflow)
- Alarm frequency and duration
- AC power and battery status
- Any unusual noise from the fan or device housing
Final Thought
Patient safety is the priority. Troubleshooting should always follow a logical, external-first approach, correcting environmental or power issues before assuming internal failure. Proper documentation ensures effective repair and reduces repeat alarms.
That is successful troubleshooting.