Ever Hear of Copper Plating Inside the Compressor?


First off, I want to thank Ulises Palacios for taking these photos. He is in the habit of cutting open the compressors he replaces to see why they failed (when possible). I think that's pretty boss.

So, why would the compressor have copper plating on the inside? They certainly aren't manufactured that way.

The short answer is that acids inside the system can eat away at the copper and brass components in the system. The copper is then deposited in the high pressure/temperature environment of the compressor.

Why does this happen?

The presence of any acids in the system can cause this to occur, but the most likely causes are the combination of air and moisture reacting with the refrigerant oil (most prevalently POE) to create an environment in which the copper is dissolved internally and redeposited on the steel in the compressor.

The result inside the compressor is reduced clearances and ultimately locking, overheating, and even short circuits if the mechanical failure results in winding damage, as is fairly common.

So, for a technician, we can ensure that we are properly evacuating the system and installing appropriate filter driers to reduce or eliminate the presence of air and moisture.

—Bryan

P.S. – For an in-depth analysis of a study on copper plating in compressors, you can read a literature search here.

Related Tech Tips

Why Selecting Equipment is Important (and Hard)
I get questions all the time about performing “load calculations” and “rules of thumb,” as well as how to do it properly. This article isn't about load calculation, but the only good answer is to find a quality ACCA-approved Manual J software and get used to using it. You may have heard from others in […]
Read more
Pressure Difference and Pump Flow
This article was written by Michael Housh, owner of Housh Home Energy and a regular contributor to HVAC School. Thanks, Michael! This is another article in trying to relate the air side of HVAC with the water side. In this article, I’m going to talk about how to determine pump flow (GPM) based on the […]
Read more
Oil Management and Diagnosis
This is a subject that even many commercial guys don’t have to consider. For the majority of equipment, even refrigeration equipment, all that is required for proper oil return is to size the suction line properly, trap the suction line as needed, and allow for proper slope towards the compressor. Then we get into larger […]
Read more

One response to “Ever Hear of Copper Plating Inside the Compressor?”

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

loading

To continue you need to agree to our terms.

The HVAC School site, podcast and daily tech tips
Made possible by Generous support from