ReplyRefrigerant for stationary equipment does not come with oil in it. That being said there would be no oil cross contamination. Always replace the filter when you open a system.
Professional Member
Had a tech top off a 410 unit with a pound or two of 22. Is it ok to just recover, flush lines, vacuum and recharge? Surely we don't need to replace equipment, right?
Global Moderator
Refrigerant for stationary equipment does not come with oil in it. That being said there would be no oil cross contamination. Always replace the filter when you open a system.
Professional Member
Good point about the refrigerant having no oil in it.
Sounds like we will go with plan A then.
Professional Member*
Happens to the best if us. Mine was a overtime call at 1am
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Professional Member
Id just change the gas . r22 has no problem mixing and running with poe oil ,Its the 410 that wont mix with the 22s mineral oil
Professional Member
You're right that a R22 system has no problem with POE oil. But this was a 410 system adding R22 to it.
Professional Member*
You are sure right when you say it happens to the best of us! A 1 hr call turn into 6.
Professional Member
You're absolutely right about that one! I have tried to explain that to our relatively new service dispatcher. She has no comprehension of exactly what the difference between a maintenance call and a repair is.Originally Posted by JKerch
For example, last week I had to do a leak search, which I told her might take a few hours, and here she goes and schedules three more call in between. Maintenance calls no less!
Professional Member
ya i know its a 410 was just saying no real need to flush as there be no sludge or anything formed as the 22 would mix ok
Professional Member
Can anyone provide documentation as to this "sludge" that you're alleging that forms when PolyolEster oil and Mineral oil mix?
Yes, I know that it is "common knowledge" that it happens, but I've got a problem with it.
See, I've SEEN POE and mineral oil mixed with no problems. I've done it on instructions from customers and engineers intentionally.
So, can anyone document it? Or are we just repeating the same old tales without spending any time to verify the truth of it?
As to the original problem, pull the mixed gas and charge it up with new. Good to go.
Refrigerant doesn't affect the oil. Doesn't matter if you put 22 in a 410a system or the other way 'round.
Professional Member
Good point could be an old wives tale but id prefer to be careful than to be caught.
Professional Member*
More like "common misinformation" from people who heard it from someone who heard it from someone who misunderstood something in a training class he was sleeping through.
Mineral and POE oil are completely compatible with each other.
Professional Member*
So as long as there is no burnout you can use R22 lineset without flushing when converting the system to R410a? No need to worry about "R22 oil" in the old lineset?
Professional Member*
SCANDALOUS, I tell you! Scandalous!
Really?
One of the more irritating realities of this trade - how certain myths and practices can be upheld or shot down according to the whim of popular thought.
Suscribed for the long hall, then...carry one.
Professional Member*
Mineral oil is not miscible with R-410A, so if excessive amounts are left in the lines, it will tend to collect in parts of the system that have lower refrigerant velocity, like the evaporator coil, and cause capacity issues.
There are no chemical compatibility or compressor lubrication issues with mixing POE and Mineral oil.
The key is to minimize the amount of mineral oil remaining in the system.
Professional Member
Thanks for clearing that up i knew there had to be some issue with it because if fitting a 410 using existing pipework most air cons use a flushing cycle to collect the mineral oil out of the system before normal use. Why would they bother if it wasnt a problem.
God Speed, Jim. We'll miss you - 2-26-23
The min oil to poe oil % mix would need to be 5%plus before any real problem would occur. If more then 5%, the min oil will fall out of solution with the POE and then could collect in areas of the evap or low spots in the line set.
Remember, when R410A first came out. Some people were saying you would have to reover the whole charge, and recharge with virgin, because it would fractionate. Which was just a myth.
Professional Member*
I know a guy who factory charged a 410 system with 22. Soon as the compressor fired up it broke just as quickly!
Carrier tech said the 2 just don't mix.
"I've got my Gas Mechanics license"
"Yea, well my 16yr old daughter has her drivers license, doesn't mean she knows how to drive"
Professional Member*
I've seen the sludge with my own eyes. A few times. All where systems that originally had mineral oil, and where converted to poe. I'm pretty sure the sludge was just baked mineral oil or burnout residue that was sitting loose in the system, and the poe "washed it loose" and kept plugging up various things with it.
I know that mixing the oils won't create sludge, rather its just that poe acts like a detergent. Putting poe in a system will break loose 20 years of crap and create the magic sludge. I don't think a lot of people are aware of this which is what propagates the myth.
God Speed, Jim. We'll miss you - 2-26-23
What was the original problem he was working on it for.
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