Hi all,

Normally I hang out in the oil analysis section, but got a filter in yesterday off a Chiller, take a look at the pics.

http://oilwatch.co.za/pics/P7310043.JPG
http://oilwatch.co.za/pics/P7310044.JPG

looks like a copper deposit, and its only on the inner material metal, not the inlet metal (which is showing up as silver).

The other filters don't have this problem.

From an oil analysis point of view. Both have similar copper values (7 ppm). Both have low Acid (TAN) 0.1. Both have highish PH (9.5) (alkaline).

The only difference is the additive pack - this filters oil has 0 P (phosphorous) and the others 700 ppm (Phosphorous). These are meant to be the same oils.

Anyway, does anyone have an idea where the supposed copper could be coming from - note these chillers do not have pumps.

Andrew

What are water/Fe concentrations of oils
Copper plating is fairly common in refrigeration world - basically dissolved copper (needs to be oxidized to be attacked by acids) carried by refrigerant from copper pipes to steel components at which takes place electrochemical mechanism: iron oxidizes/copper reduced to metal. If iron oil soluble you would see an increase in iron in oil, if oil insoluble, iron containing sludge near copper plating. Presence of water promotes. TAN really couldn't build since would attack copper oxide on copper surfaces. P additive would protect non wearing iron surfaces - water decomposes many P additives