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.
York Central Tech Talk 
Mike,
Is your opinion that this a new issue based on some chemical reaction, or do you suspect it is the result of poor installation practices or poor cleanup after a compressor failure? We primarily service larger commercial and industrial equipment and while the TXV’s themselves are larger, if this were a chemical reaction issue, I would still expect to see accumulation of contaminants on the pin and seat as shown in your photos. We have not seen this.
Harry
right now, the ‘jury is out” on this. I would personally think it is due to poor installation practices but I’ll wait to see what the final chemical analysis is of the “gunk”. I just wanted to make sure people are aware of this and that they do proper TXV diagnostics and, if they have aproblem, to make sure the clean the system up properly.
It would seem unlikely that suddenly techs all over the country got worse in their installation practices. I would look for a common supplier across the HVAC brands (like Copeland) that somehow introduced a new manufacturing practice or chemical into their product.
right now it is a “mystery”. The cure is to put in over-sized driers when replacing the valve. All manufacturers of equipment are experiencing this. Sporlan is looking into it as the attached bulletin stated. I’m just trying to make everyone aware of the situation and REMIND them that “good service/installation practices” go a long way in preventing problems. It will be interesting to see what the “cause” of this is gointg forward.
Trane and Nordyne has issued additive bulletins to clear TXV clogging.
Trane
Click to access UN_SVB020A_EN_TXV_Sticking_Bulletin.pdf
Nordyne recommends Nu-Calgon AC Renew.
Click to access 3-80.pdf
Some are also reporting Supco88 oil additive works.
http://www.supco.com/Chemicals%20pg7.htm
Speculation is that Copeland or their supplier change an oil formulation.
Thanks for all the information — our company will becoming out shortly with the same (NU Calgon AC Renew recomendation
I haven’t seen it yet. Time to count my lucky stars… this would be a nightmare of mass proportions.
I had this problem on some new Refrigeration units that fail after a week of installation. the pin looks stock with that glue looking thing.