R-22 TO 407C

[valdelocc]

Are you asking about that RTAA you converted? I'm not so sure I can help with your question, but it would help anyone to know what control panel is on it. If you don't recall that, then what tonnage is it? Or you can describe the panel.

In the password protected menu there a "refrigerant type" point, the choices are "r22 134a and 404a" if one was to change the settings from r-22 to any of the other 2, would the control reconfigure itself and the chiller to run in such refrigerant?

[DANI25486]

Have to say that I agree with you for the most part. The only real issue that comes up is the oil that carries out into the condenser is in blobs, sort of like the stuff in an old Lava Lamp, since the oil doesn't mix with the refrigerant. This can lead to somewhat erratic feed thru the expansion valve. Something that can be done to skirt the issue is to drain part of the mineral and replace with POE, since the POE will mix with the mineral and the refrigerant. We've done this and had very good success.

Back to the original question by the OP, unless this is a first run YCAS, it already has POE and shouldn't be an issue.

Are you sure what you saying.....because I´ve done retrofits from R22 to R407C, most of the times when the compressor failed and then changed. Even the new compressor comes with POE oil, when we start it, after 2 minutes we could see in the oil sightglass all white, looks like snow, We had to make 2 more changes of oil for it became clear.
My conclusion was R407C does not admit any mineral oil.

Other 2 situations that you should take in care is that when you changed MIN to POE, the POE is more acid then MIN, so it will work as a solvent in refrigerant circuit, all rust will be dissolved in oil, other is, old compressors have the winding not prepared for the POE, it will damage the winding isolation bacause of the same problem.

[valdelocc]

Are you sure what you saying.....because I´ve done retrofits from R22 to R407C, most of the times when the compressor failed and then changed. Even the new compressor comes with POE oil, when we start it, after 2 minutes we could see in the oil sightglass all white, looks like snow, We had to make 2 more changes of oil for it became clear.
My conclusion was R407C does not admit any mineral oil.

Other 2 situations that you should take in care is that when you changed MIN to POE, the POE is more acid then MIN, so it will work as a solvent in refrigerant circuit, all rust will be dissolved in oil, other is, old compressors have the winding not prepared for the POE, it will damage the winding isolation bacause of the same problem.

POE is not acidic,they oil sight glass was "white" cause of the refrigerant traveling with the oil, 407C is 7% miscible with mineral oil. In a chiller equipped with an oil separator, the oil travels by means of pressures differentials.
The compressors windings are the same with POE or MO, POE is a strong solvent thats all.

[GT1980]

There are a few examples of a couple years success on line searching 407 from 22. and you can call those successful comm/inds service cos.

[EMETH]

Why change the oil? I challenged engineers to give me a good reason and none of them could, just because somebody wrote "change the oil" on a piece of paper, doesn't mean you have to do it. R-22 is 33% miscible with mineral oil, the oil separator removes 98% of the 33% oil that travels with the refrigerant, 407c is 4%to 10% miscible with mineral oil and the oil separator removers 98% of the 4% of the oil that travels with the refrigerant,the capacity of the oil separator would be enhanced by an non-miscible refrigerant, in a package chiller the little oil that is carried away by velocity will be brought back by the same forces.

I have heard this before on the limited miscibility of R22 but have not been able to locate citations on this; can you provide sources?

Thanks

[valdelocc]

I have heard this before on the limited miscibility of R22 but have not been able to locate citations on this; can you provide sources?

Thanks

I actually got the numbers from an article written by Wes Taylor, he was an old time RSES member and senior engineer with Carlyle compressors. I dont have a link to it.

[klove]

Are you sure what you saying......

Yes, I am.

[EMETH]

I actually got the numbers from an article written by Wes Taylor, he was an old time RSES member and senior engineer with Carlyle compressors. I dont have a link to it.

In searching around, I found a NEWS article from February 6, 2006 titled

“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."

[humbled daily]

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.

[highhead666]

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

[EMETH]

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.

No offense taken; dialogue on the subject is always welcome.

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.

[EMETH]

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

Interesting question.

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.

[jpsmith1cm]

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.

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.

[GT1980]

When proper procedures.... ...anyway.

Good2U. agreed.

[pony]

I have convert r22 to r407c without change oil but i did ad supco88 oil into system,it is my rental property,just experimenting see how it go,will see if any problems this summer!

[stanbyyourword]

Amen to the mineral oil clumping up in high side when using 407c! You can see it in sight glasses!

the gloop

[DANI25486]

I have convert r22 to r407c without change oil but i did ad supco88 oil into system,it is my rental property,just experimenting see how it go,will see if any problems this summer!

the oil wont return to compressor....that additive dosent garanty it. R407C isn´t mixible with MINERAL OIL....

[DANI25486]

I converted the RTAA to 407c without changing the oil, its been running without problems for over a month.

It still working good? Did you change oil to POE?

[pony]

I see many post with peoples done it with and without oil change,i want to know the ture!i will find out soon enough after this summer!if compressor gone or not!

the oil wont return to compressor....that additive dosent garanty it. R407C isn´t mixible with MINERAL OIL....

[DANI25486]

I see many post with peoples done it with and without oil change,i want to know the ture!i will find out soon enough after this summer!if compressor gone or not!

It´s your machine....please keep us updated.