Yes, I am.
Originally Posted by Carlos Daniel
In searching around, I found a NEWS article from February 6, 2006 titled
Originally Posted by valdelocc
Are R-404A and Mineral Oil Incompatible?
The most relevant portion to the discussion at hand is:
"Transport is a complex function of various parameters, such as velocity of the refrigerant through the pipes, degree of solubility, viscosity of the oil-refrigerant mixture, refrigerant density, operational temperatures, and pipe sizing and layout."
"It is also well known that refrigerants like R-22 or R-502 are not fully miscible with mineral oils, but maintain partial solubility and have been used successfully for many years."
"It is also well known that hydrocarbons have a very high solubility in mineral oils. Additionally, they have total miscibility with fluorocarbon refrigerants."
"This relationship results in a mutual solubility effect when the refrigerant blend is mixed with mineral oil, for example."
"Substantial amounts of the fluorocarbon refrigerant will also dissolve in the oil sufficiently, providing the necessary oil transport properties."
I am going to take a step back on this one, if the main concern is the cost of R-22, then why not focus on the main issue of containing the loss of refrigerant, if you convert and o rings shrinkage is a valuable concern, then wouldn't you be opening the door to increased refrigerant losses,do not mean to make it sound like I am belittling you for one second, but your thread leaves the door wide open for this question. Please advise.
I work on rtaa and other chillers which are r-22. Should we consider changing them to 407c if there's no refrigerent issues. or change it over before there is. It sounds like oil should be changed again about a month after to be sure , the LL drier should be changed as well I would assume
No offense taken; dialogue on the subject is always welcome.
Originally Posted by humbled daily
Well, yes the cost of R22 IS a concern because the warehouse manager has brought the issue of long-time procrastination to the forefront.
Our district has in the neighborhood of 10,000 units, perhaps as much as 85-95% R22; we should have come to the 410A party years sooner than we did, but that's bureaucrats for you.
We only began the conversation on R22 retrofit alternatives in January of 2012 and no one in authority had the resolve to take action until the warehouse manager said he wasn't buying any more R22.
Some people just kept topping off leaking systems without repairing leaks.
So far, the units that permit easy MO removal and POE installation (such as semi-hermetics, some scrolls that have removable oil sight glasses on the compressor and new compressors that can be emptied of MO and replaced with POE, assuming the new compressor isn't shipped with POE) have had all o-rings, cores, driers, etc. replaced and any leaks repaired.
All of our retros thus far have shown no signs of problems, whether changed to POE or not.
Thus far, there is no commitment to a wholesale retrofit program, but rather a gradual “drawdown”, shall we say, to accommodate our R22 reclamation program.
Originally Posted by highhead666
It is alleged that chillers with flooded evaporators are problematic due to fractionation of the component refrigerants in the blend.
Thus far, we have only retrofitted 1 chiller with two chiller barrels.
All MO was removed and replaced with POE; o-rings, driers, etc. were replaced.
It's an old POS McQuay with badly deteriorated condenser coils, totally enclosed within 12 foot high concrete walls, and the subject of years of piecemeal patching and jury rigging.
It runs high head due to not being able to get the condenser air out of the enclosure.
Currently running as well on 407C as it was on 22; fractionation hasn't been a problem.
In your case I would say it's up to the equipment owner.
Originally Posted by humbled daily
When proper procedures for retrofitting are followed, leakage isn't really an issue.
Depending on the equipment, following those proper procedures can be costly and time consuming, but not as costly and time consuming as NOT following them.
The issue is that R-22 expands the o-rings. The sudden absence of R-22 causes them to return to normal size. After having been expanded in the groove for so long, they typically take the shape of that groove.
When they return to "normal" size, they lose the ability to seal and that is when the leaks occur.
Installing new o-rings eliminates this issue in the short to medium term (can't say about the long term, yet)
Once we worked the kinks out, we don't have too many leaks on 407a retrofits after the fact. Those leaks that DO happen would have happened with 22, anyway.
R22's procedure anyway
Originally Posted by jpsmith1cm