GE Healthcare NM/CT 870 CZT

Cooling, Fan, or Overtemperature Fault Occurs

On this page

Asset Type

PET / CT System

Manufacturer

GE Healthcare

Model

NM/CT 870 CZT

What This Guide Helps With

Cooling warnings, abnormal fan behavior, or overtemperature conditions occur because of blocked airflow, room conditions, contamination, or a system cooling fault.

Step-by-Step Troubleshooting

1. Protect the Patient and Respond to Heat-Related Warnings

If the system reports an overtemperature condition, shuts down unexpectedly, produces an unusual odor, or becomes abnormally hot, stop the examination and safely remove the patient.

Do not repeatedly restart equipment that may be overheating.

Expected outcome: Patient care is no longer dependent on equipment with a potential cooling or thermal fault.

2. Confirm the Exact Thermal Condition

Record the exact warning or message and identify whether staff reported a fan fault, excessive heat, unexpected shutdown, unusual noise, or room-temperature concern.

Determine whether the condition appeared during startup, idle operation, or active acquisition.

Expected outcome: The thermal problem is clearly defined and its operating context is documented.

3. Check Room Environmental Conditions

Verify the imaging room and equipment area are being cooled normally and ask whether HVAC service, room-temperature excursions, construction, or facility outages recently occurred.

Escalate room-conditioning problems to Facilities rather than treating them as scanner failures.

Expected outcome: The room environment is appropriate for continued troubleshooting, or a facility cooling problem is identified.

4. Inspect External Airflow Paths

Inspect accessible vents, air intakes, exhaust areas, equipment clearance, and surrounding space.

Remove external items blocking airflow. Do not open internal covers solely to clean or inspect fans unless authorized.

Expected outcome: External airflow paths are unobstructed.

5. Inspect for Dust or External Contamination

Check accessible ventilation surfaces for obvious dust buildup, lint, packaging material, or other contamination that can be safely removed according to approved maintenance practices.

Expected outcome: External ventilation surfaces are clean enough to permit normal airflow.

6. Listen for Abnormal Fan Operation

From outside the equipment, note whether normal airflow or fan operation appears absent, unusually loud, intermittent, scraping, or otherwise abnormal.

Do not insert tools or objects into vents.

Expected outcome: No obvious external evidence of failed or obstructed cooling hardware is present.

7. Allow the System to Return to a Safe Condition

If the system stopped because of heat and there is no evidence of smoke or electrical damage, keep it out of clinical use and follow approved manufacturer procedures for recovery.

Do not bypass thermal protections to speed the process.

Expected outcome: The system no longer indicates an active unsafe thermal condition before further testing.

8. Perform a Controlled Restart When Appropriate

Only after environmental and airflow conditions are acceptable should an approved restart be attempted.

Monitor for recurrence of the warning, abnormal fan noise, odor, or unexpected shutdown.

Expected outcome: The system initializes without a thermal warning and remains stable. If the fault returns, stop testing and escalate.

9. Verify Operation Under Appropriate Test Conditions

If the system remains normal, complete required operational and quality-control testing before clinical use.

Observe whether the fault returns during normal nonpatient activity.

Expected outcome: Cooling remains stable and the system completes required functional verification. The issue is resolved and troubleshooting can stop.

10. Escalate Recurring Thermal or Fan Faults

Remove the system from service if a thermal warning recurs, a fan appears nonfunctional, abnormal heat persists, or the equipment shuts down again.

Do not operate the scanner with covers removed or bypass cooling interlocks.

Expected outcome: Potential internal cooling, power, or thermal-monitoring faults are evaluated by qualified service personnel.

If the Problem Persists

External airflow obstruction, room HVAC condition, accessible contamination, and basic environmental causes have been ruled out. Remaining categories may include internal fans, filters, cooling assemblies, temperature sensing, power electronics, internal airflow restrictions, or other service-level thermal conditions.

The device should be:

Complete thermal stability, operational, and required quality checks before return to clinical service. Knowing when to stop external troubleshooting is proper troubleshooting.

Clinical Use Tip

A thermal fault that clears after cooling down is still unresolved if the cause of the overheating has not been identified or stable operation verified.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
"Staff reported an overtemperature warning on the NM/CT 870 CZT during operation."

Cause

What was observed during troubleshooting.

Example:
"Clinical Engineering found equipment stored against an external ventilation area, restricting normal airflow."

Resolution

What action was taken.

Example:
"Clinical Engineering cleared the ventilation area, verified normal room conditions, completed an approved restart and functional checks without recurrence, and returned the system to service."

Helpful Details to Include (If Known)

Final Thought

Overtemperature conditions require conservative handling: protect the patient, verify the room and airflow first, never bypass thermal protections, and return the system to use only after stable operation is demonstrated.

That is successful troubleshooting.

Related Guides

Was this guide helpful?

Don't see a guide you need?

Suggest a Guide