Copper plated drier shell

[james mo]

Trane air cooled chiller circuit B. 6 years old.. Repaired a leak at a braze joint in the discharge line of one of the two 50 HP screws and found this in the drier shell.

[T1371]

I wonder if anyone in the past ever used a sawzall to cut piping during repairs or replacements. I had a job where I had a 5H open drive compressor go bad. I opened up the crank and it was full of copper and silver shavings. Came to find out that the Evap coils in the Penthouse had been replace but were put in backwards so they had to remove them again to put them in right. Then they put them in upside down and had to repeat the process. Well they used a sawzall to cut the piping over and over again . also I'm sure you could imagine how much silver soldier was used...... I filled the palm of my hand with copper and silver that i scooped out of the oil sump.....

[John Culpepper]

Looks like electroplating to me.

[bertoh]

6 years old i assume r134a is the refer??? start with onsite oil acid test kit,also a lab oil analysis. would recomend a refer lab analysis (liquid phase). i would imagine it is moisture in the system, which becomes acidic at high temp discharge and is eating away at the inside of copper piping and getting picked up at drier core.was it opened for repairs, or a leaker from factory that didnt get evacuated right?
if its acidic but in high capacity driers and new oil with acid away and get it cleaned out after a few changes of oil and cores

[freonguy]

A one word answer - ACID !!:eek:

You will find your acid level is high - no ifs, ands or buts.

Great photos by the way.

[jayguy]

an acid test is probably in order. an oil sample probably is not. you already know what it is going to tell you...high copper. and if it did not tell you that, would you trust it? so, i would not bother with that. on some of the Trane centrifugals, the manufacturer of the copper tubing used a greenish colored lubricant when they cut the inner and outer tube rifling. sometimes they did not get the lubricant cleaned off properly (i guess trane did not want to clean them either). the lubricant held on to the copper chips and shavings and this is what ended up in the machine. i have not heard of this being a problem on the screws (different factory), but i suppose it could.

i would perform an acid test, change out the filter driers and the oil, meg the compressor (you do not want any of the copper in the windings), cross your fingers, etc. continue monitoring for a while. after all of the change outs, THEN i would start to perform oil analysis. keep an eye on the other circuit as well.

let us know what you find.

good luck.

[bertoh]

lab oil analysis should tell wayer PPM , Ph level, TAN and metal contents at least. that will give you an indication of how many drums of oil and drier cores you need and if you need to change 24 hours later , next week, next year etc.refer sample will tell you if you need that recycled back to near virgin status.
or field test oil, lick the point of your index finger, see which way the wind is blowing and get the f out of there.
you will have saved him hundreds on the tests, and opened the door the rest of us to quote on that replacement. soon!!

[hvacker]

You can't have copper plating without acid in the system.
This could have happened at a previous burnout but who knows.

Some of you probably remember when refrigerants were vented after a burnout and you could find your gauges copper plated.

Started out brass, ended up copper.

[jayguy]

lick the point of your index finger, see which way the wind is blowing and get the f out of there.


i wish some of our sales engineers knew how to do this.

good luck.

[RobY]

an acid test is probably in order. an oil sample probably is not. you already know what it is going to tell you...high copper. and if it did not tell you that, would you trust it? so, i would not bother with that.

I think there is alot of utility in doing oil analysis, but I probably have a biased opinion ;-)

The oil after copper plating occurrs actually has very little copper left. The symptoms of a copper plated system are high acidity, high iron and low copper. The copper exchanges with the iron as it electroplates out of the oil.

If you are doing oil analysis and see high copper, high acidity and low iron, you have a potential copper plating problem, and may have time to get the system corrected before it gets worse.

There is an ASHRAE research project on copper plating that is just about to be published that looks at the chemical mechanism. The key parts of the mechanism for copper plating is oxidation of the copper surface, followed by dissolving of the copper oxide in acidic oil. The acidic oil also causes corrosion of an iron surface, and the copper dissolved in the acidic oil exchanges with the corroded iron surface. Acidic oil won't attack base copper metal, so unless it is oxidized, no copper plating will happen.

The easiest way to promote copper plating is to allow air and moisture into the system. A clean dry system will not copper plate.

Rob Yost
National Refrigerants

[bertoh]

The easiest way to promote copper plating is to allow air and moisture into the system. A clean dry system will not copper plate.
well said robY. or alternatively ignore all the good advice and tools available to us ie. oil analysis , and lick that finger to find out what way the wind is blowing. you might as well know something leaving site!!

[jayguy]

after all of the change outs, THEN i would start to perform oil analysis. keep an eye on the other circuit as well.


i did not say to never do any oil analysis. we have performed oil anaylsis on blatantly obvious problems before, only to be told that we need to change the oil, filters, etc. i only stated to do what is quite obvious first...not to wait for an oil analysis to tell you the very same things. oil analysis is a very valuable tool that i recommend to just about all customers. but when faced with this current problem...

good luck.

[poppop]

Although I believe that air, moisture and acid will lead to copper plating, I do not believe all copper plating is caused by air, moisture or acid. We test our oil and refrigerant on an annual basis and still run into situations of copper plating where acid and moisture are not present... especially when dealing with synthetic oils and HFC134a. I'm not so sure the manufacturers of these chemicals know all the properties their products possess.

[txhvac]

Screw compressors sounds like an RTAA 100 ton or so. This is an R-22 machine w/ oil 15- (300). Get an oil analysis, pull your oil filter and see if anything is in it. Replace oil filter, & drier cores (of course). It is possible to collect copper in the oil/refrigerant circuits from the chiller barrel, I'm not saying this is the case, but it is possible. Meg your comp. motor, be prepared to pipe in a suction can, & for proper clean-up, drier changes & oil changes. Take a field oil acid test sample, & send one off for analysis. Just be glad you don't have steel shavings in the filters.:D Hope this can help.

[james mo]

This is an RTAA-100. I removed all of the refrigerant due to the location of the leak and the quantity left. I evacuated it below 500 microns and installed high acid drier cores. I will follow up with oil analysis after reading the responses. I didn't think of the oil filter though.....

[socal13]

I think itsa finger an if a its a green it might be due to mostiure in tha system