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What This Guide Helps With
Troubleshoots failed temperature verification caused by setup, simulator condition, probe placement, mode, stabilization, accessories, environment, or internal measurement faults.
Step-by-Step Troubleshooting
1. Protect the Patient and Remove the Thermometer From Clinical Use
Do not use a thermometer that has failed calibration verification or produces results outside the approved verification criteria. Provide another verified thermometer.
Label the affected unit to prevent accidental use during evaluation.
Expected outcome: No patient temperature is measured with equipment whose accuracy is uncertain.
2. Confirm the Verification Method and Failure
Review the exact test method, equipment used, thermometer mode, displayed reading, expected reading, and acceptance criteria. Use only current approved manufacturer or facility procedures.
Do not invent tolerances or use informal comparison methods.
Expected outcome: The reported failure is confirmed against the correct documented procedure.
3. Verify the Test Equipment Is Suitable
Confirm the temperature simulator, calibration device, or verification bath is approved for the thermometer and has current calibration status. Inspect its cable, adapter, well, fluid level, and accessories as applicable.
Verify the reference equipment was allowed to warm up or stabilize according to its own instructions.
Expected outcome: The test equipment is appropriate, within calibration, and operating normally.
4. Confirm the Correct Probe and Probe Well
Verify that the correct compatible probe and matching probe well are installed. Inspect the probe tip, cable, connector, and well for contamination, damage, or moisture.
Expected outcome: Compatible, intact, clean, and dry external components are being tested.
5. Verify the Correct Measurement Mode
Confirm that the thermometer is set to the mode required by the approved verification procedure. Do not assume oral, axillary, pediatric, or monitor modes are interchangeable.
Expected outcome: The device is tested in the specified mode. If the incorrect mode caused the discrepancy, repeat the verification correctly.
6. Inspect Probe Placement in the Verification Device
Ensure the probe is inserted to the correct position required by the approved verification setup and remains stable throughout the measurement. Avoid contact with surfaces not intended by the test method.
Expected outcome: The sensing area is positioned consistently within the approved test fixture.
7. Allow Adequate Environmental and Equipment Stabilization
Move the thermometer, probe, and test equipment away from direct airflow, sunlight, heating vents, cold storage, or recent transport between temperature extremes.
Allow all components to reach a stable testing environment as required by the approved procedure.
Expected outcome: Environmental instability is removed as a source of verification error.
8. Repeat the Test Without Changing Multiple Variables
Repeat the approved verification using the same known-good setup. Record each result rather than relying on memory.
If the result passes consistently, investigate whether the original failure was caused by setup or stabilization.
Expected outcome: Repeated results are stable and reproducible. A consistent pass allows progression to final functional checks.
9. Test With a Known-Good Compatible Probe
Install a verified compatible probe and repeat the approved verification. Do not adjust internal calibration simply because one probe fails.
Expected outcome: The known-good probe passes, identifying the original probe as the cause, or the thermometer still fails and requires further evaluation.
10. Compare With Another Verified Thermometer
Use the same calibrated verification equipment and method to test another compatible thermometer. This confirms that the verification setup itself can produce an expected result.
Expected outcome: The comparison thermometer passes. If both devices fail similarly, stop and investigate the reference setup rather than adjusting either thermometer.
11. Inspect for Intermittent Connections
During nonpatient verification, observe whether the reading changes or drops out when the probe cable rests in different normal positions. Do not flex the cable aggressively.
Expected outcome: The reading remains stable. An intermittent probe, connector, or receptacle requires removal from service.
12. Stop and Escalate a Confirmed Verification Failure
If the SureTemp Plus 692 fails the approved verification with calibrated test equipment, correct mode, stable conditions, and a known-good probe, do not alter calibration through unauthorized procedures.
Expected outcome: The thermometer is removed from service and sent for qualified calibration or repair evaluation.
If the Problem Persists
External and procedural causes involving the test method, reference equipment, probe, mode, placement, stabilization, and environment have been ruled out. The remaining condition may involve internal measurement electronics, probe interface circuitry, stored calibration data, temperature-processing circuitry, or another service-level fault.
Remove the thermometer from service, label it Out of Service, and send it for repair, calibration, or bench evaluation. Use appropriate Welch Allyn documentation and approved calibrated test equipment. Calibration adjustments and internal repair should be performed only by qualified authorized personnel.
Before return to service, the thermometer must pass the complete approved verification procedure, operate correctly in required modes, and complete repeated functional measurements. Knowing when to stop external troubleshooting is proper troubleshooting.
Clinical Use Tip
Never use agreement with another unverified clinical thermometer as proof of accuracy; use calibrated, approved temperature-verification equipment.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"The SureTemp Plus 692 failed its scheduled temperature accuracy verification."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found that the probe was not inserted to the required position in the approved verification device, causing unstable readings."
Resolution
What action was taken.
Example:
"Clinical Engineering corrected the probe placement and repeated the approved test, with the thermometer passing all required verification checks."
Helpful Details to Include (If Known)
- Verification procedure used
- Reference equipment identification
- Calibration status of test equipment
- Required and displayed temperature
- Acceptance criteria from approved documentation
- Probe and probe-well type
- Measurement mode
- Environmental conditions
- Probe placement
- Known-good probe result
- Comparison thermometer result
- Final pass or fail status
Final Thought
Accuracy verification must be controlled, repeatable, and based on approved calibrated equipment. Rule out setup, mode, probe, placement, and environmental causes before assuming internal failure, and never return a failed thermometer to service without a documented passing result.
That is successful troubleshooting.