TXV Issues?


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.

Parker-Sporlan TXV letter to HVAC Industry 7-29-14

ADP Informational Bulletin 8-4-2014 (1)

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About yorkcentraltechtalk

I have been in the HVAC industry most of my life. I worked 25 years for contractors on anything from residential to large commercial boilers and power burners. For the past 23+ years I had been employed by York International UPG Division ( a division of Johnson Controls) as a Technical support/Service Manager but I am now retired. One of my goals has always been to "educate" dealers and contractors. The reason for starting this blog was to share some knowledge, thoughts, ideas, etc with anyone who takes the time to read it. The contents of this blog are my own opinions, thoughts, experiences and should not be construed as those of Johnson Controls York UPG in any way. I hope you find this a help. I always welcome comments and suggestions for postings and will do my best to address any thoughts, questions, or topics you may want to hear about. Thanks for taking the time to read my postings! Mike Bishop
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9 Responses to TXV Issues?

  1. 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.

  2. rjp says:

    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.

  3. rjp says:

    Trane and Nordyne has issued additive bulletins to clear TXV clogging.

    Trane
    https://gallery.mailchimp.com/c9906d742d7d84d15ab61c654/files/UN_SVB020A_EN_TXV_Sticking_Bulletin.pdf

    Nordyne recommends Nu-Calgon AC Renew.
    http://www.nucalgon.com/assets/prodlit/3-80.pdf

  4. Ray Austin says:

    I haven’t seen it yet. Time to count my lucky stars… this would be a nightmare of mass proportions.

  5. Nino says:

    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.

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