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

TXV Bulb Placement
When mounting a TXV bulb or checking bulb placement, there are a few important considerations (listed in order of importance): Mount the bulb on the suction line. Flapping in the breeze is no good. Mount it TIGHTLY with a proper metallic strap (usually copper, brass, or stainless steel)—not with zip ties or tape. Position it on […]
Read more
4-20ma Control Basics
Back in the “good old days,” controls were all analog and mechanical, which simply means that they acted in a directly connected and variable manner based on a change in force. Both pneumatic (air pressure) or hydraulic (fluid pressure) systems are examples of mechanical or analog controls. When the pressure increased or decreased on a […]
Read more
Glide at Static Pressure
We've been pretty spoiled in residential and light commercial in the USA because we haven't needed to deal with glide much. R22 has no glide, and R410a is a near-azeotropic blend, which means it has almost no glide. The days of being able to ignore glide are coming to an end. Carrier has announced their […]
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