Reply to Thread

Just finished retrofitting this old Trane SAHA with new compressor and 407c, running POE oil, did an oil and dryers change this morning to flush system contaminants.

FYI guys,

Our school district is now well into our third year of retrofitting R22 units with 407C. None of the hundreds of units retro'd have had any problems, even the ones we left MO and added Supco.

Also, FYI, Supco EXPANDS rubber o-rings and seals, thus preventing the leaks you would normally see when going from HCFC to HFC refrigerants.

I agree with Mikey about using 407 with mineral oil. I have not seen problems with it either. I would recommend adding the oil bypass kits to the compressors if you do it. And only use York L oil or an equivalent. Replacing dryers goes without saying. Keep us updated.

In my own house I am working on my second summer with a mineral oil compressor running R-407C. It a rotary compressor - so it doesn't have much oil in it to start with. It's a 15,000 BTU compressor with a 1 1/8" suction line - so I Know it ain't gas velocity bringing the oil back. <g>

I have a number of customers with R-407C running over mineral oil in RTU's, split systems, and one medium temp refrigeration split - 5 HP on a dehumidifier I built.

In addition to the all-mineral oil systems I have done all kinds of other things: added Supco 88, added a few percent POE oil, on one refinery unit we added about 5% propane. I have tried adding pentane too.

So far as I can tell they all run just as well if I do nothing: just run the 407 right over mineral oil without changing anything else.

If R-407 causes a problem running over mineral oil - I have certainly failed to see it yet.

Residential customers are thrilled that I can convert them to the new refrigerant - without having to change out their entire systems - like everyone else told them they Had to do. <g>

PHM
------

Originally Posted by 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!

Did this change out on a YCRS three years ago. Changed the dip switch , changed out the L oil for new L oil . Checked superheat , everything worked good. Have not any leaks on orings as of yet. The small loss of tonnage actualy helped , less compressor cycling during light load.

I am currently working on a ycas as well. They are talking about the o rings in the compressors. I am changing them now due to leak after installing a new slide valve spring and external oil bypass. You have to pull the compressor apart. Not very hard but time consuming. There is also a dip switch change you have to make for 407. Looking through the manual I found an optional suction line heater for 407c. I think you are asking for some headaches if you change refrigerants. The ycas has York L oil. It's a POE already. Once you open the compressor you will be replacing the oil anyway.

When u talking O ring will leak when u convert from r22 to r407c without change oil,what O ring ur talking about?ur mean internal leaking or external leaking?

Originally Posted by 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!

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

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!

Originally Posted by DANI25486

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

Originally Posted by valdelocc

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?

Originally Posted by 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!

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

Originally Posted by sargent york

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

the gloop

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!

R22's procedure anyway

Originally Posted by jpsmith1cm

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

Good2U. agreed.

Originally Posted by 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.

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.

Originally Posted by 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

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.

Originally Posted by 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.

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.

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

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.

Originally Posted by valdelocc

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."