On this page
Asset Type
Manufacturer
Model
What This Guide Helps With
Troubleshooting cycle interruptions or over-temperature faults caused by hot solution, insufficient fluid, excessive load, heavy use, or unresolved temperature sensing problems.
Step-by-Step Troubleshooting
1. Ensure Patient and Staff Safety First
Remove the ultrasonic cleaner from use during evaluation. Do not process instruments in a unit that stops during operation or displays an over-temperature condition.
Allow the tank, solution, baskets, and instruments to cool before handling. Wear appropriate personal protective equipment when removing potentially contaminated instruments or solution.
Expected outcome: Staff are protected from hot solution exposure, and no instrument processing depends on a cleaner with an unresolved temperature fault.
2. Verify the Reported Fault and Operating Conditions
Confirm whether the display reported an Over Temp, Unit Over Temp, or temperature-related fault during an active cleaning cycle.
Document:
- Whether the fault appeared immediately or after repeated cycles.
- Whether the unit contained heated or unusually warm solution.
- Whether the tank was heavily loaded.
- Whether the cycle stopped or could not be restarted.
Midmark identifies over-temperature conditions when tank liquid is above 60°C / 140°F. Midmark also identifies a separate unit over-temperature condition related to excessive internal base-plate temperature.
Expected outcome: The reported condition is confirmed and tied to actual operating circumstances rather than an unverified complaint.
3. Check Solution Temperature
With the unit no longer running, safely verify whether the tank solution is excessively hot.
If the solution is above the unit’s normal operating range or is noticeably overheated, allow it to cool. When appropriate, drain a portion of the hot solution and replace it with properly mixed cooler solution according to department process.
Do not restart the unit until the solution temperature is below 60°C / 140°F.
Expected outcome: The tank solution is within an acceptable temperature range and the fault does not immediately recur.
If resolved: Complete a normal test cycle with an appropriate load, confirm normal operation, document the findings, and return the device to service only when safe.
4. Verify Correct Fluid Level
Inspect the tank and confirm it contains sufficient cleaning solution for operation. Check for signs that the unit was run with low fluid, such as solution below the required fill level or unusually rapid heating.
Confirm the level-sensing area is not obstructed by debris or contamination.
Midmark identifies insufficient fluid during operation as a possible contributor to a Unit Over Temp condition.
Expected outcome: The tank is properly filled, the solution is contacting the level-sensing area, and the cleaner operates without overheating.
If resolved: Perform a normal cycle test and stop troubleshooting.
5. Check for Excessive Instrument Load
Inspect the basket load. Remove excess instruments, stacked trays, or unusually heavy contents that may overload the bath or prevent proper energy distribution.
Reload the cleaner using a reasonable instrument quantity and repeat a monitored test cycle with the unit unoccupied by clinical workload.
Midmark lists an overloaded bath or large instrument mass as a possible cause of a unit over-temperature condition.
Expected outcome: The cleaner completes the cycle normally with an appropriate load.
If resolved: Advise the department on avoiding excessive loading, document the correction, and return the unit to service.
6. Check for Repeated or Continuous Use
Ask the department whether the unit was being used for repeated back-to-back cycles without adequate cooling time.
If heavy use is reported, allow the unit and solution to cool fully, then run a monitored test cycle with proper fluid level and a normal load.
Midmark identifies consistent operation without adequate time to cool as a possible cause of Unit Over Temp.
Expected outcome: The unit operates normally after cooling and does not fault during a properly loaded test cycle.
If resolved: Return the cleaner to service with guidance to monitor repeated-cycle operation.
7. Inspect External Condition and Ventilation
Confirm the cleaner is installed in its normal operating location and is not surrounded by items that could trap heat or interfere with normal cooling.
Inspect externally for:
- Blocked surrounding airflow.
- Excessive heat around the base or cabinet.
- Unusual odor, discoloration, or visible damage.
- Evidence of fluid leakage.
Do not remove covers or perform energized internal inspection during this troubleshooting process.
Expected outcome: No external installation or environmental condition is contributing to overheating.
8. Evaluate for an Intermittent or False Temperature Fault
After the unit has cooled, the solution level is correct, and the bath is properly loaded, perform one monitored test cycle.
If the unit again reports an over-temperature fault despite normal fluid temperature, proper loading, and reasonable use, suspect an internal temperature-sensing, control, or ultrasonic generator cooling problem.
Midmark’s troubleshooting information identifies sensor-related temperature faults when abnormal temperature readings occur during a cycle.
Expected outcome: A repeat fault under normal conditions confirms the problem is not corrected by external adjustments.
If the Problem Persists
If the QuickClean continues to display an over-temperature fault after verifying solution temperature, fluid level, loading, use pattern, and external condition, common external causes have been ruled out. The fault is likely related to an internal temperature sensor, control component, base-plate temperature condition, or other repair-level issue.
The device should be:
- Removed from service.
- Labeled Out of Service.
- Sent for repair or bench evaluation.
Do not continue repeated cycle testing on a unit that continues to overheat or reports temperature faults under normal operating conditions. Knowing when to stop and escalate is proper troubleshooting.
Clinical Use Tip
Do not release instruments for clinical use when the cleaning cycle was interrupted by an over-temperature fault unless they are reprocessed according to departmental infection-prevention procedure using verified functioning equipment.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Clinical staff reported that the Midmark QuickClean QC Series ultrasonic cleaner stopped during operation and displayed an over-temperature fault."
Cause
What was observed during troubleshooting.
Example:
"Found the tank solution excessively hot after repeated back-to-back cycles with a heavily loaded basket; fault did not recur after cooling and correcting the load."
Resolution
What action was taken.
Example:
"Allowed the unit to cool, restored proper operating conditions, completed a successful monitored cleaning-cycle test, and returned the cleaner to service."
Helpful Details to Include, If Known
- Exact displayed message: Over Temp, Unit Over Temp, or temperature sensor-related fault.
- Solution temperature at time of evaluation.
- Fluid level verified.
- Level-sensing area inspected for contamination.
- Instrument load condition.
- Number of back-to-back cycles reported.
- Any unusual heat, smell, leakage, or visible damage.
- Result of monitored test cycle.
- Final device status: returned to service or removed from service.
Final Thought
An ultrasonic cleaner that overheats during operation may have a correctable external cause, such as hot solution, low fluid, excessive loading, or continuous use. Clinical Engineering should rule out these conditions logically, protect staff and instrument processing integrity, and escalate promptly when the fault repeats under normal conditions. Complete CCR documentation supports safe equipment decisions and future service history.
That is successful troubleshooting.