The purpose of this post is to provide service guidance to address erratic thermal expansion valve performance which reportedly results in observed high superheat conditions and at times, coincidental with compressor failure in residential and commercial split and package A/C & HP systems.
Reports of failures of this type have been industry wide in recent weeks. Instances of this failure mode have been very isolated , but when experienced, proper practices must be followed to accurately diagnose the problem and restore system performance. (See posts on TXV diagnostics)
These problems have been observed across both residential and commercial equipment. Suppliers and other industry experts are actively engaged to identify and confirm root cause and corrective action.
Certain practices can minimize repeat instances when this problem is observed. For example, reports of repair success using Sporlan Catchall HH style or equivalent oversized filter/driers coupled with replacing the TXV. At this time, this approach is considered best practice, while other approaches are being evaluated. Also, ALWAYS be sure to use a nitrogen trace whenever brazing on a system and be sure to achieve a 500 micron evacuation to assure moisture is out of the system.
Be sure to read the attached informational letters from both Sporlan and ADP but this is an INDUSTRY WIDE issue affecting ALL MANUFACTURERS.