Refrigeration Oils

[johnny01]

I work for a supermarket chain in Texas , we have been losing quite a bit of compressors lately . Superheats are not too bad , a couple of years ago we switched over from alkybenziene to mineral oil , I am thinking the mineral oil is breaking down too soon and causing the out of the ordinary compressor losses . I am thinking about going back to Alky ... Any comments on oils ?

[Tesla]

Hi Johnny01
First confirm diagnosis with some oil samples tested at the lab, checking acid(moisture), metals and sludge. Check discharge temps too. High temperature, moisture and sludge leads to mineral oil breaking down, problem with racks is it's a lot harder to clean them up after a burn out. In saying that it depends on the refrigerant used and oil return from lo temps.

[Magoo]

What refrigerants are you using?. And what grade of mineral oil are you using currently ?.
magoo.

[Magoo]

Hi Johno1, I think I spotted your reply in an old post about oil etc..,
Along the lines of multi temp., racks and R22.
Sounds like you may have a problem with cross contamination with oils, a chemical reaction. R22 is not miscable with oil, and oil will end up in all parts of system, so changing oil type eventually oil will migrate from system and mix in compressors, so chemical reaction between oils and oil viscosity changes and compressor failures.
magoo

[US Iceman]

What are the types of compressor failures? Motor burnouts (electrical or acid), mechanical (normal or induced by say oil slugging), or something else?

The type of failure should provide a hint at what the root cause may be...

[joe magee]

I'm curious,Why did you change the oil? US iceman hit it on the head. How are the compressors failing? Do you break them down to see what type of failures occur.

[lowcool]

going from alkylbenzene to mineral sounds to me like incompatabilty to refrigerant was never keen on alkylbenzene,figured it was just another sales pitch as refrigerants were when phasing out cfcs