Mixing of oils.

[stephen90]

So I have began to do a small amount of research on oils mixing. From what I can gather, at first this was thought that even very small amounts of oil mixing would cause sludge, breakdown, etc. But more recent information from some sources states that slight mixing/contamination of oils is not really an issue. For instance using the same gauge set for poe and pve. Yes poe undergoes hydrolisys a pve does not, but as far as I understand it, the oils themselves do not react in any adverse way to coming in contact with each other. Why then do most manufactures still say not to allow any Cross-contamination at all? My understand that good purging practices with your manifold would be enough and I haven't really seen evidence that using separate gauges and hoses for different oils is necessary. Having a separating hose set for burnouts/dirty systems seems more important than different oils.

[TechmanTerry]

What sources? I remember the original rule of 95% poe vs 5% mineral.

A seperate set of gauges for burnouts?? Please explain? I use F/D in line on burnouts.

[jayguy]

The issue of “mixing oils” has nothing to do with the oil. It has to do with converting from one refrigerant to another when the new refrigerant requires a different oil. The concern is if there is too much of the previous oil in the system, the oil may not travel through the lines properly and return to the compressor in a timely manner. Sure, there could be a chemical compatibility issue between the different types or brands of oils, but we really haven’t seen that issue.

[stephen90]

It seems to me that rather than the manufacturers (I am currently going through some manufacturers training) placing an emphasis on never ever mixing oil (they recommend completely separate gauges for ea H type of oil) it would make more sense to emphasize making sure contaminates from a burnout or known system that was contaminated.

[stephen90]

I know that mineral oil is not miscible with 410a. Doesn't mean one tiny drop of mineral oil would hurt a system. What I am really focusing on is is that a manufacturer stating that you cannot use gauges for poe and pve. I just haven't seen any evidence that it would actually cause an issue. 1 if purging your gauges thd amount of oil left woulc be extremely small and 2 they are both miscible with 410 the biggest difference is one breaks down in the prescense of moisture the other absorbs it but doesn't turn into acid

[2sac]

I'm pretty sure I have read somewhere that 10%-15% is acceptable.

As far as the paranoia....don't worry about it. Refrigeration techs have been dealing with different refrigerants and oils since 1995 when 12 was outlawed. There have been a few hurdles here and there, but it's not as bad as you think.

[TechmanTerry]

Well at my last Copeland COSS thing, we were notified that a 50% poe/50% mineral oil is now "OK". A set of hoses for each oil? Mineral,Alke-Benzene,POE,PVE.?

[2sac]

Well at my last Copeland COSS thing, we were notified that a 50% poe/50% mineral oil is now "OK". A set of hoses for each oil? Mineral,Alke-Benzene,POE,PVE.?

Need 2 sets of hoses. One for systems with dye, and one for systems without dye....I hate dye

[icy78]

Just did an 06E from 22 to 407C.
Carlisle wants 30% POE.
RTU 50ton. Theres only mineral oil in there right now. Returning like a champ. But, I disabled it now till next spring. Want to watch it run unloaded for a while.

Sent from my SM-G950U using Tapatalk

[R600a]

My understanding is that pag doesn't mix with mineral oil but all others mix any way you like.
The only problem is when you have mineral oil and it has some moisture from improper installation and service techniques and you add poe to it then you have a problem.

Sent from my rotary telephone using Tapatalk

[stephen90]

Thanks guys. Why are certain manufacturers still stating such strict policies? CYA essentially?

[71CHOPS]

Thanks guys. Why are certain manufacturers still stating such strict policies? CYA essentially?

a manufacturer is always going to state never to mix oils, never use generic parts, etc. etc. they are protecting their equipment (and their butts). If they, even once say (officially) that it's ok to mix oils, then someone has a compressor failure within the warranty period, they would be responsible for the coverage.

If someone has a compressor failure within the warranty period, and the manufacturer finds that they have mixed oils, there is no coverage.


I use the same manifold and gauge set on everything. If I think I may have picked up some contaminates, I'll just blow everything out with nitrogen. If you want to get extreme, use some lineset flush.

As was stated, mixing oils isn't as big of an issue as was originally thought. manufacturers are coming around apparently, evidenced by Terry saying copeland is now officially stating a 50/50 mix is OK. last class I went through with them, it was unofficial. Nothing is official with any manufacturer unless they put it in a publicly released document addressing the issue, though.

[icemeister]

So I have began to do a small amount of research on oils mixing. From what I can gather, at first this was thought that even very small amounts of oil mixing would cause sludge, breakdown, etc. But more recent information from some sources states that slight mixing/contamination of oils is not really an issue. For instance using the same gauge set for poe and pve. Yes poe undergoes hydrolisys a pve does not, but as far as I understand it, the oils themselves do not react in any adverse way to coming in contact with each other. Why then do most manufactures still say not to allow any Cross-contamination at all? My understand that good purging practices with your manifold would be enough and I haven't really seen evidence that using separate gauges and hoses for different oils is necessary. Having a separating hose set for burnouts/dirty systems seems more important than different oils.

It's true that back in the early days a POE oil being used in HVACR there was a strict warning from OEMs to use a dedicated manifold gauge set for POE systems. This rule, along with the one for 5% max residual mineral oil, gradually were disproved...unofficially. Now after more then 25 years the separate gauge set mandate has essentially disappeared and there seems to be some cracks in the OEM's 5% mineral oil edict.

[hvac69]

Need 2 sets of hoses. One for systems with dye, and one for systems without dye....I hate dye

Yeah the second set are the guys set who put the dye in.

[Juan Madera]

I have one set of gauges just for 134a systems. 134a and cap tubes are a pita so I do not want any chance of cross contamination. One set of gauges for all the others...