Change out line sets?

[rgar2019]

Do you need to replace the line sets when switching from R-22 to 410? I was told by some that you definitely must as the oils are different between the two and any residule oil from the R-22 will cause damage. Others have told me that its perfectly safe and acceptable to use the existing lines, however, do a R-11 flush, nitrogen purge and evac. system. Whats your opinion on this method?

[beenthere]

Lines can be reused.

[superheatbob]

You will get mixed anwsers on this. Several companies make a cleaner that is flushed thru the line and cleans it, must be done thorughly. Cost is less than new lines in most cases.

I designed one of the flush systems on the market today. We used a very expensive solvent also used by nasa, and used by computer manufacurers to clean hard drives in clean rooms. It is very effective at removing ALL grease oil, etc. NASA cleaned space shuttle parts with it.

One company calls it "Rx-11" because the solvent is similar in properties to the old R11 freon. The cleaner evaporates at just over 100 dergrees,so not much chace of residue left. Trick is to always flush DOWNHILL, use plenty and blow with nitrogen.

Linesets also must be the right size to re-use, which usually emliminates at least 50% of the old ones if not more. Too small a line reduces both efficiency and capacity, meaning your new 3 ton ac may now only produce 2 3/4 or even 2 1/2 tons. Or a 13 seer is about 11.9 or so...

But you can't beat a new line set for cleanliness and to help insure unit system longevity.

[zw17]

I designed one of the flush systems on the market today.

Could you explain your role in the design of this flush system?

How is it 'like' the old R-11 and not the exact same?

[superheatbob]

I'll not promote any products from former companies or go into details other than to say we sourced cannisters and injection tools, tested techniques and worked with chemists, evaluated chemicals used for results, etc. Did the marketing, etc

The flush chemical has very similar properties, boiling point, lack of residue, superb degreasing power etc ...just like the old R-11 we knew and loved.

The same chemical is used by two companies, a third uses a different one.
One uses R-134A as a propellant in a self contained cannister, the other two push with a nitrogen cylinder.

R-11 was an actual refrigerant used for years.

"R X 1 1" is a flushing substance made by a chemical company. It does not actually contain R-11 a CFC that has long been illegal to vent.

"R 'X' 11" is a 'take off' of the old R11 refrigerant name by a chemical company, sort of a play on words like...."RX the prescription for cleaning linesets, etc".

[heaterman]

As to the original post, yes they can be reused if they meet the requirements of the new equipment and they are properly flushed. When in doubt, toss it out! We change all line sets when ever possible. No doubts about anything related to that part of the system then.

[superheatbob]

I forgot to add one thing.

If the failure was a burnout, the lineset MUST be changed. As good as the flushes are, just a few molecules of acid left behind will be big trouble!

[beenthere]

That isn't true either.

Many compressors are changed out after a burn out, and the line set isn't changed.

[superheatbob]

Let me put it this way. It is TRUE from some manufacturer's standpoints.

I just watched the using nittrogen when soldering video. Your statement 'This is not true' is like saying, "you don't have to use nitrogen when soldering! Many systems have been installed without running nitrogen thru linesets."

I am sure "many systems are installed without a vacuum pump", too. That doesn't mean it's good procedure.

It is STRONGLY RECCOMENDED to prevent failure to change a lineset when you have had a burnout IF YOU ARE CONVERTING TO R410A.

(Which is what this thread is about!)

If you leave any mineral oil in an old lineset it is risky if you convert the system to R410A.

If you leave ANY ACIDIC OIL in a system that you are now going to convert to R410A with sensitive contaminant-loving POE oil, you have a very chance of falilure. It is borderline stupidity.

To do R410A right requires we leave our old R-22 bad habits from the past behind.

Is that better language for you?

[beenthere]

Read Carriers instructions. No need to change line set.


Comparing changing line sets, and flowing nitrogen. Is like comparing diesel fuel storage to a cars gasoline MPG.

You will probably be seeing retracts to the MO and POE mixing in the not too distant future.

[superheatbob]

I don't doubt they said that. They also said use coils back to 1992 in one memo I think.

Carrier is becoming the new Goodman. They will do anything to sell a box.

As mentioned earlier this would be controversial, There are manufactuer's, guidelines..'loosening' as they get desperate.

And there are best practices. Which makes sense and let you sleep easier at night.

[beenthere]

The question, isn't best practice.
Its, must it be changed? The answer is NO.

[hvacvegas]

I use the type of flush with the nitrogen. 2 cans minimum per lineset, and more depending upon smell/color of the flush coming out the end. I've flushed plenty of burned out linesets. We just used additional cans, to be careful.

superheatbob, would you be willing to explain how the flush has "superb degreasing power", how can it not remove acid from a line?

Although, it is always (in my mind) advisable to replace a lineset, if economically/physically feasible.