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.

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

Leave a Reply

Your email address will not be published. Required fields are marked *

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

Related Tech Tips

Zonal Pressure Diagnostics—The Backtalk Series (Part 3)
This article was submitted by Genry Garcia of Comfort Dynamics, Inc. It is the final part of his series on zonal pressure diagnostics. Thanks, Genry! Updated 3/4/2022 Picking up where we left off in part 2 of the series, we discussed how a pressure reading from an attached zone indicates only the ratio of the […]
Read more
500 BTUs per Person Per Hour?
I heard a great presentation by Ron Auvil on VAV systems, and it got me thinking… Can you size a commercial system/perform a block load by the number of occupants? Yes!  No, I'm just kidding. That's crazy talk. There is way more to it than that. However, in a commercial environment, while the building's perimeter […]
Read more
HVAC Contractors Guide to COVID-19 (SARS-CoV-2, Coronavirus)
UPDATED VERSION AS OF 4/1/2020 As HVAC contractors, we are tasked with keeping staff and customers safe during the outbreak, and we are relied upon to provide some guidance to customers about how to protect themselves against the virus in the air. For employers and employees looking to navigate the new FMLA/FFRCA legislation, we put […]
Read more
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