Overheard a guy at the supply house say something about compressor oil that stuck with me

I was grabbing a capacitor at Grainger yesterday and heard this older tech tell a kid that he only uses POE oil on R-410A systems, no exceptions. Said he's seen 5 compressors fail from guys mixing mineral oil in just the past 3 years here in Austin. It got me thinking - do you all stick to a specific brand or type of oil for different refrigerants, or do you just grab whatever's on the shelf?

2 comments

2 Comments

carr.willow1mo agoMost Upvoted

Wait, do people actually still use mineral oil on 410A systems? That sounds like a great way to kill a compressor fast, I've heard the same horror stories from old timers.

rowank691mo ago

I had a call last year where a guy's 410A system was running fine for about 6 months after a buddy "helped" him top it off with mineral oil. @carr.willow you're absolutely right, that stuff just doesn't mix with the POE oil and it turns into a sludge that kills the compressor. I had to replace the whole outdoor unit because the mineral oil gummed up the scroll valve so bad you could hear it grinding from 10 feet away. If you ever see a system that's been cross-contaminated, be prepared to do a full line set flush and check the TXV too because those are usually toast as well lol.