Understanding Active Dissipation
July 10, 2025
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Along with new refrigerant for 2025, we’re also seeing new components for safety to be compatible with new Federal guidelines.
Have you ever seen a stuck TXV?
Carrier typically uses hard shutoff valves on their equipment. A hard shutoff TXV means that when the unit turns off and the system pressures equalize, the TXV needle will fully close.
Where would you see stuck TXVs? / What are the key indicators?
So, if you have a stuck TXV, what can you do to assist this issue? Do a TXV Ice Bath.
After charge is confirmed/verified/ corrected (by subcool) and airflow is known to be good.
Allow the unit to run nonstop for a minimum of 10 minutes. Do not turn the system off at all for these tests.
Step One: Record the suction pipe temperature at the indoor unit.
Step Two: Remove the TXV bulb from the suction line, hold it in your hand and warm it by rubbing it with your thumb, do not use a lighter.
Step Three: After 2 minutes of holding the bulb in your hand, record the suction pipe temperature again.
Step Four: Take a cup of ice, add just enough water to cover the ice, then put the sensing bulb into the ice water.
Step five: After 2 minutes in the ice, record the suction pipe temperature again.
Step six: Remove the sensing bulb from the ice water, then reattach it to the suction pipe.
Step 7: After 2 minutes of being reapplied to the suction pipe, record the suction pipe again.
Note: if you feel the need, repeat the steps as many times as you like, but typically only one time is necessary.
When done, you should have written down or recorded 4 suction pipe temperature readings. Review the before and after results to determine if the valve is still stuck or if it is now functioning.
Normal operating TXVs should have a very noticeable temperature swing (typically 10F or more) on the suction pipe when changing from ice to hand or vice versa.
If you correct a TXV sticking one time, it is all good and should be free and clear of issues. However, if you catch it sticking again, it is recommended to schedule a replacement. A repeating issue of sticking TXV could eventually lead to a premature compressor failure.
Disclaimer: The technical statements, information and recommendations contained herein are believed to be accurate as of the date hereof, but Mingledorff’s does not make representations or warranties, express or implied, as to its accuracy, its completeness, or the results to be obtained. The information is being provided for informational purposes only and is intended for use by persons having adequate skill and expertise regarding the proper selection, use and application of the products and recommendations and at their own risk and discretion.
Along with new refrigerant for 2025, we’re also seeing new components for safety to be compatible with new Federal guidelines.
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