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Manufacturer
Model
What This Guide Helps With
Cooling or temperature alarms caused by blocked airflow, room conditions, coolant issues, chiller problems, or heat-related system faults.
Step-by-Step Troubleshooting
Ensure Patient Safety First
If the scanner is in use or a patient is on the table, stop scanning safely and follow department protocol.
Move the patient off the scanner if continued troubleshooting could delay care or create risk.
Expected outcome: Patient care is not dependent on a scanner that may be overheating or unable to complete imaging safely.
Verify the Reported Alarm
Confirm the exact cooling or temperature alarm shown on the Canon Aquilion console.
Check whether the alarm appears:
- At startup
- During tube warm-up
- During scanning
- After heavy patient volume
- Continuously, even when idle
Expected outcome: The alarm behavior is confirmed and documented.
Why it matters: Intermittent heat alarms after heavy scanning may point to cooling capacity or room temperature issues, while immediate alarms may indicate sensor, chiller, coolant, or internal hardware faults.
Stop Scanning and Allow the System to Stabilize
If the scanner reports overheating or temperature out of range, do not continue scanning.
Allow the system to cool according to site policy and scanner status indicators.
Expected outcome: Temperature-related warnings may clear after the system returns to an acceptable operating range.
If this resolves the issue: Return the scanner to service only after verifying normal startup, no active temperature alarms, and acceptable operation.
Check Room Temperature and HVAC Conditions
Verify that the CT room temperature is within the site’s required operating range.
Look for:
- Room unusually warm
- HVAC failure
- Closed or blocked vents
- Recent facilities temperature complaints
- Excess heat from nearby equipment
Expected outcome: CT room environmental conditions are normal.
Why it matters: CT scanners generate significant heat and depend on stable room cooling. A room HVAC issue can trigger scanner cooling alarms even when the scanner itself is not defective.
Inspect External Airflow Around the Gantry and Cabinets
Check for blocked intake or exhaust areas around the gantry, operator console, power cabinets, and equipment cabinets.
Look for:
- Linens, boxes, carts, or supplies blocking vents
- Dust buildup on external vent areas
- Equipment pushed too close to walls
- Panels not fully seated
Expected outcome: Airflow paths are clear and nothing external is restricting ventilation.
If this resolves the issue: Clear obstructions, allow the system to stabilize, and verify the alarm does not return.
Check for Obvious Cooling Unit or Chiller Issues
If the site uses an external chiller or dedicated cooling unit, inspect it from the outside only.
Check for:
- Power present to the chiller
- Chiller running normally
- Displayed chiller alarms
- Unusual noise
- Visible leaks
- Blocked ventilation around the chiller
- Temperature or flow warnings
Expected outcome: The cooling unit is powered, running, and not showing obvious external faults.
Why it matters: A scanner temperature alarm may originate from the cooling system, not the CT gantry itself.
Check for Visible Coolant Leaks
Inspect around the gantry, cooling cabinet, chiller, and visible coolant lines where accessible.
Do not open internal covers or disconnect coolant lines unless trained and authorized.
Look for:
- Puddles
- Wet flooring
- Drips
- Crusty residue near fittings
- Low coolant warning on the cooling unit
Expected outcome: No visible coolant leak is present.
If a leak is found: Remove the scanner from service and escalate for repair.
Check Power to Supporting Cooling Equipment
Verify that cooling-related equipment is connected to the correct power source and that breakers or disconnects have not been unintentionally switched off.
Check only accessible facility power sources and approved disconnects.
Expected outcome: Cooling support equipment has stable power.
Why it matters: Loss of power to the chiller or cooling cabinet can create temperature alarms even if the CT scanner console still powers on.
Review Recent Work or Environmental Changes
Ask whether there was recent activity that may have affected cooling.
Examples:
- HVAC maintenance
- Electrical work
- Chiller service
- Room rearrangement
- Cabinet moved or blocked
- High scan volume
- Recent water leak or facility issue
Expected outcome: Any recent change is identified and corrected if related.
Restart Only if Safe and Appropriate
If there is no leak, no burning smell, no overheating condition, and no active cooling equipment fault, perform a controlled system restart according to site procedure.
Expected outcome: Temporary software or sensor communication faults may clear.
If the alarm clears: Monitor the system during startup and warm-up before returning it to clinical use.
If the alarm returns: Do not continue repeated restarts. Escalate.
Check for Unusual Heat, Smell, or Noise
While the system is idle, observe for abnormal signs.
Look for:
- Excessive heat near cabinets
- Burning smell
- Loud fan noise
- No fan noise where fan operation is normally expected
- Chiller vibration
- Repeated coolant pump cycling
- Alarm returning shortly after reset
Expected outcome: No signs of active overheating or equipment distress are present.
If heat, odor, or abnormal noise is present: Remove from service immediately.
Confirm Final Scanner Status
Before returning the scanner to service, confirm:
- No active cooling or temperature alarms
- Room temperature is acceptable
- Chiller or cooling unit is operating normally
- No visible leaks
- No abnormal odor, heat, or noise
- Scanner completes startup and readiness checks
Expected outcome: Scanner is safe and ready for clinical use.
If the Problem Persists
If the Canon Aquilion CT scanner continues to show cooling system or temperature alarms after external checks are completed, common external causes have been ruled out.
The issue may involve an internal cooling circuit, temperature sensor, coolant pump, fan assembly, chiller interface, heat exchanger, power supply, or scanner control fault.
The device should be removed from service, labeled Out of Service, and escalated for repair, vendor support, or bench/system evaluation.
Knowing when to stop is proper troubleshooting. Continued scanning with unresolved temperature alarms can risk equipment damage, failed scans, image quality issues, or patient care delays.
Clinical Use Tip
Do not troubleshoot a CT scanner cooling or temperature alarm with a patient waiting on the table unless patient safety has already been addressed. Move the patient to another scanner or coordinate with clinical leadership before extended troubleshooting.
Therapy and patient care continuity should come first. Do not continue troubleshooting on an active patient when a backup scanner or alternate imaging plan is needed.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"CT staff reported a Canon Aquilion scanner cooling system alarm during patient scanning, preventing further exams."
Cause
What was observed during troubleshooting.
Example:
"Room temperature was elevated and airflow around the equipment cabinet was partially blocked by stored supplies."
Resolution
What action was taken.
Example:
"Removed airflow obstruction, notified facilities regarding room temperature, allowed system to stabilize, verified no active temperature alarms, and returned scanner to service."
Helpful Details to Include (If Known)
- Exact alarm message displayed
- Whether alarm occurred at startup, idle, warm-up, or during scanning
- Room temperature at time of failure
- HVAC condition
- Chiller status or alarm display
- Any visible leaks
- Any unusual heat, odor, or noise
- Whether airflow was blocked
- Whether system was restarted
- Whether alarm cleared or returned
- Final device status
- Vendor or facilities escalation details
Final Thought
Cooling and temperature alarms on a CT scanner should be handled carefully because they can affect patient flow, equipment reliability, and scanner safety. Start with patient safety, room conditions, airflow, visible leaks, and cooling support equipment before assuming an internal scanner failure. If the alarm does not clear after basic external checks, removing the scanner from service and escalating is the safest and most professional response.
That is successful troubleshooting.