The purpose of this post is to provide UPDATED service guidance to address erratic thermal expansion valve performance which results in observed high superheat conditions, at times coincidental with compressor failure.

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.

In conjunction with compressor suppliers, many manufacturers have confirmed and are authorizing the use of the following chemical additive to restore system performance. This additive effectively dissolves the contaminant debris on the TXV components and restores system operating performance. Use of the additive offers a more cost and time effective approach, in lieu of opening the system, replacing driers and replacing the TXV.

You do need to check with your specific manufacturer as to how they are going to approach the “restricted” txv issue. 

I have attached Nu-Calgon’s instructions for use of the additive. As additional information is released concerning long-term reliability assessment and proactive field actions, I will try to keep you up to date on that information.

NUCALGON RENU instructions




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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11 Responses to TXV Issues — UPDATE

  1. NELS CARLSON says:

    So what your saying is that by adding this additive into a system that all ready has a restrictive TXV valve will clear it up with out removal?

  2. It looks like magic bullet, fix for everything. How it works? And if it so good, why manufacturers don’t add it at the factory?

  3. jejoss@comcast.net says:

    Thank you for the post!

  4. Steve Hewitt says:

    How many contractors actually flow nitrogen when they are brazing? I’m sure this could be one of the problems. Also I would start looking at the compressor manufactures, and maybe start considering the wire they are using for the windings. What changed? are they buying cheap wire from china with a different coating or something else along those lines? My dad is in the magnetics industry and they had a problem with transformers shorting in the turns. Found out it was the wire that was purchased because the purchasing agent found a “good deal” on the same wire from a supplier that was actually coming from China and not the same wire.

    • The cause is still being investigated. But, regardless, it is our job to make sure our customers get to use the equipment they paid for. If adding a “additive” to the system cleans it up and allows it to operate, that is a very simple fix to a very big problem. I’m am confident that the root cause will be found and corrected but, for now, we need to take care of our customers.

  5. Pete Singh says:

    If this product works , this will give a big break in mantainance of AC system, need more info

  6. Rogue Reign says:

    OMG!!! Years of a crappy very expensive York Condenser… and I finally find your post to fix the issues. I can’t tell you how amazing your site is. I’ve had 3 contractors out here and wanted to strangle every one of them. “It’s not cooling right”… and they found nothing telling me “it’s charged right, it’s fine.” Now… this year it’s really screwing up… started locking out and it’s blowing hot… no refrigerant can be added and I’m thinking… is the compressor out? Checked everything… tested everything… replaced capacitor and contactor and fan… and it’s running great but still… hot air and locking out. Researching hours and hours on the internet… and here it is… the answer to my frustrations… THANK YOU!!! P.S… our AC supply has never even heard of A/C renew… clueless people here I wonder how many others are as frustrated as I am with such a simple fix.

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