TXV/Piston Replacement

The metering device is the component in your HVAC system that determines how much refrigerant passes through the lines at a time. Some base efficiency air conditioners and heat pumps still use a simple piston device, however, manufacturers are moving towards thermal expansion valves which are required to meet SEER levels in high efficiency models. TXV's may either be factory or field installed in your system's air handler. 


 In 2014 a manufacturing defect was discovered that was causing premature failures in many models across most manufacturers. That is because manufacturers use many of the identical components and vendors. A temporary solution of using MJ-X oil additive until the issue was resolved. This issue has been mostly resolved but your TXV may still fail due to other issues including:

  • foreign material in orifice

  • excessive moisture in system

  • adjusted too far closed

  • wrong oil used in system

If you're having issues with your metering device, your system may continue to operate albeit poorly. A technician will be able to identify the fault through low evaporator suction pressure, low condenser split, short cycling, low compressor amp draw, high evaporator and compressor superheats and low condensing head pressure.

Contact Melo Air today if you suspect you have an issue with your TXV or piston metering device.

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Melo Air Inc

550 N Reo St Suite 300

Tampa, FL 33609

(813) 451-9438