Flush New Line sets with R-11 instead of flowing Nitrogen?

[hairy]

I'm planning to have two new R-410A systems installed to replace some old R-22 equipment. So far the various contractors have agreed that new line sets are in order. That's fine with me - that's what I want.

I asked the most recent fellow (established contractor/owner) if he'd flow nitrogen while brazing the new line sets and he confidently said, "No, he would not." He says he has a better method. What is it? After brazing he likes to run an R-11 flush through the lines - he claims it does a much better job and even suggested that flowing nitrogen was an outdated method. He talked a few minutes more about how expensive this little container of R-11 was and how it didn't make sense that it was still available what with all the environmental concerns surrounding R-22 and all. Puzzling indeed...

I didn't know what to think other than something didn't sound right. So after some reading today I learned that due to EPA regulations the real R-11 is no longer supposed to be available. So I figure maybe he really meant he's using the Rx-11 Flush substitute or something like it. Who knows....

But regardless of what he might be using as a flush, my real question is this:

Does it make sense when brazing a new line set to skip flowing nitrogen in favor of some follow-up R-11 type flush? Is this in any way preferable, superior to, or a substitute for flowing nitrogen while brazing? Wouldn't this method just run the risk of introducing other contaminants into an otherwise clean line set?

I know a flush makes sense for burnouts or when re-using lines for r410 that were previously charged with r22, but on new lines? Any thoughts on this new twist to the nitrogen flow / line set replacement debate is appreciated?

[Swampfox]

Lets see...

prevent oxides from forming in the first place, or let them form and then attempt to flush them out with something after the fact.

what sounds like the better option?

nevermind the flush is much more expensive than nitrogen, literally an ounce of prevention is worth a pound af cure in this case.

[iraqveteran]

We don't flush new linesets. Braze em up and dry nitro pressure test. Triple Evac and your all set ready to go.

Systems now-a-days have filter dryers to remove contaminants from the system. So a flush is IMO an un-neccessary step. But if the contractor wants to spend extra money, make sure its not out of your pocket.

[hvaclover]

nitrogen is ok to use.. But if your brazer is good at what he does (ie; FORMIN THE BRAZE WITH OUT over heating the copper thus accounting for little to no scale) then nitro really is not a necessity as a generously sized LL filter drier will pick up any small traces tha could have formed.
I can oly speak for my self so if you are using somebody fror the first time you should expect a nitro flow.

[ampulman]

..... a generously sized LL filter drier will pick up any small traces tha could have formed.


If the filter/drier is in the condensing unit, what happens to any scale formed at the braze of tubing (LL) to evaporator?


AM

[hvaclover]

If the filter/drier is in the condensing unit, what happens to any scale formed at the braze of tubing (LL) to evaporator?


AM

I put the filter drier at the evap inlet. And there is also a screen in the TXV in let also.

[I_bend_metal]

I asked the most recent fellow (established contractor/owner) if he'd flow nitrogen while brazing the new line sets and he confidently said, "No, he would not." He says he has a better method. What is it? After brazing he likes to run an R-11 flush through the lines - he claims it does a much better job and even suggested that flowing nitrogen was an outdated method. He talked a few minutes more about how expensive this little container of R-11 was and how it didn't make sense that it was still available what with all the environmental concerns surrounding R-22 and all. Puzzling indeed...


Sounds to me like this guy is trying to impress you with his "knowledge". Fact of the matter is there is no better way to braze linesets than with a nitrogen purge. I do understand (as stated above) that if you don't heat the joint hot enough then you have nothing to worry about....however can you trust someone to do that every time??? It takes years of experience to be that good with brazing and besides that what temperature is too hot and how do you measure it? 410 systems need to be brazed with a nitrogen purge or soldered with stay brite #8...then evacuated to at least 400 microns THREE times, breaking each with a pound or two of nitrogen. There would never be any kind of reason to run that Rx-11 flush through a brand new lineset....if this is being added to the cost of your install....IMO it's nothing you should have to pay for....sounds to me like he is using it to try and show some kind of value...when in fact it just plain unnecessary.

[DPSwitch]

Ummmmm.... the guy is a retard........ I'd get someone else.

Its like saying that its good to smoke as long as you have a good heart surgeon.

[jrbenny]

nitrogen is ok to use.. But if your brazer is good at what he does (ie; FORMIN THE BRAZE WITH OUT over heating the copper thus accounting for little to no scale) then nitro really is not a necessity as a generously sized LL filter drier will pick up any small traces tha could have formed.
I can oly speak for my self so if you are using somebody fror the first time you should expect a nitro flow.Bull poop

[I_bend_metal]

Bull poop


Thanks...I now have pop running out of my nose and onto my keyboard :D

[DPSwitch]

And there is also a screen in the TXV in let also.

That would be the one that will clog with the black stuff when you are leaving the job if you didnt nitro-flow.

[beenthere]

So how does the filter catch the oxidation on its outlet side. Its after the filter.
There are many excuses for not using nitrogen.




To the OP:
I'm sure he meant RX11 flush. It works great, and should have notrogen used to blow it out of the line set.
So that contractor is kind of off target at having any great advantage over not flowing nitrogen while braziing.

[hvaclover]

So how does the filter catch the oxidation on its outlet side. Its after the filter.
There are many excuses for not using nitrogen.




ng.

Yeah there is! The tank is really heavy.

[beenthere]

Yep, the tank is heavy.
The torch is heavy too. So do you flare your line sets.

[DPSwitch]

Never mind clover, I think he's having a bit of Nitro trolling fun..... lol

[mark beiser]

The product the contractor is talking about is probably Rx-11 flush, it is not R-11 refrigerant. It is a rather expensive flush solvent.
I hope he at least follows the flush with a LOT of nitrogen, and a triple evac.
It is still not a substitute for flowing nitrogen while brazing the lines on.


nitrogen is ok to use.. But if your brazer is good at what he does (ie; FORMIN THE BRAZE WITH OUT over heating the copper thus accounting for little to no scale) then nitro really is not a necessity as a generously sized LL filter drier will pick up any small traces tha could have formed.
I can oly speak for my self so if you are using somebody fror the first time you should expect a nitro flow.

It doesn't matter how skilled the person doing the brazing is, if he gets the copper hot enough to flow brazing alloy into the joint, significant oxidation will be formed on the inside of the pipe if there is oxygen present.
The factory installed liquid line filter driers that most manufacturers use are rather small, some have only a tiny screen in them that can easily be partially plugged by the flakes off the inside of the copper from brazing the lines. Not to mention that most of the scale has to go through the compressor first, where it can plate bearings, and other metal surfaces in the compressor.

Not flowing nitrogen while brazing is just lazy and is a violation of every manufacturers installation instructions I have seen, and is contrary to what is taught by industry training organizations.

[beenthere]

Never mind clover, I think he's having a bit of Nitro trolling fun..... lol
LOL..
No, just pointing oout that you can always find an excuse not to do, or use something.

[DPSwitch]

Nawww I meant clovers trollin not you... lol

[hairy]

Thanks everybody, I appreciate the input. I just wasn't quite sure how line flushing vs. nitrogen flow would stack up. This helps quite a bit.

Looks like my search for a qualified contractor continues.

[beenthere]

Nawww I meant clovers trollin not you... lol
LOL. Could be. :)

[hvaclover]

Bull poop

"Bull poop" all you want youngster. Nitro is not a cure all to prevent system contamination.

If too much heat is used even nitro won't completely and I EMPHASIZE COMPLETELTY help.

Cut a cross section open of a joint that was overheated with nitro in it and compare it to one that was made with a good control of the heat applied to form the joint.

Of course if a person does not braze well enough it won't work either way..

[jrbenny]

I love it when old timers get on their bandwagon. Gives me a good chuckle.

[DPSwitch]

Bull poop......


lol

[DPSwitch]

Brazing requires some pretty dang hot copper, I reckon we can agree on that ..... to expect anyone to control heat by judging different shades of red is splitting hairs.

I find alot more problems with cold joints than from any overheating.

Control of oxidation is to control oxygen.

[hvaclover]

I love it when old timers get on their bandwagon. Gives me a good chuckle.

Band wagons are for those who have not established themselves yet.

I have my financial well being and thirty years in business to back up what I say.

If I didn't know what I was talking about I would not have either of them.

[DPSwitch]

If I didn't know what I was talking about I would not have either of them.

Then you should know better than to advocate brazing without nitro.... cmon man.

[platchford]

Yep, the tank is heavy.
The torch is heavy too. So do you flare your line sets.

LOL, theres a solution! We can flare every one of our joints! Thinking outside the box FTW. (I know your kidding) :p

[hvaclover]

Then you should know better than to advocate brazing without nitro.... cmon man.

Damn it, I never advocated NOT using nitro. I said that I personally don't think it's needed if a guy can braze good enough.

It was my personal OPINION, ok?

Don't agree with it, fine. Do your own thing.

My crack about the tank being too heavy was sarcasm in case no body got it.

[jrbenny]

Yep, next thing they tell is how long they've been doing it wrong. LOL. I love it.

[DPSwitch]

Damn it, I never advocated NOT using nitro. I said that I personally don't think it's needed if a guy can braze good enough.

It was my personal OPINION, ok?

Don't agree with it, fine. Do your own thing.


lol.......

ok man.

[hvaclover]

lol.......

ok man.

Don't you know us "Oldtimers" are crotchety:rolleyes::D

[hvaclover]

Yep, next thing they tell is how long they've been doing it wrong. LOL. I love it.

Just picture your self sixty or seventy years ago. With out all the toys we have available to day.

Would you be able to trouble shoot and balance like you do today?

Would you even know where to begin?

[coolperfect]

Flow nitro through a 1/4 inch resi line while brazing you guys got to be kidding

[I_bend_metal]

Who uses 1/4 inch lines in resi these days??

[marlboroman]

you guys crack me up...

[beenthere]

Humpty Dumpty had that same problem.
May he rest in piece.

[coolperfect]

Yea Your Rite 3/8

[jrbenny]

Just picture your self sixty or seventy years ago. With out all the toys we have available to day.

Would you be able to trouble shoot and balance like you do today?

Would you even know where to begin?
Pitot invented something a long before you were born. ;)

[coolperfect]

Let me ask you guys a question We have a running unit that we find a leak on we braze the coil or any other place in the system as needed rite what happens to the oil and zero pressure gas thats in the existing unit that we just heated to 1500f I would guss worse than scale brazing with air in the line but thats what drier does cleans these problems

[jrbenny]

Sorry, but the drier just doesn't get it done. Your crap finds it's way to metering devices and screens.

[beenthere]

A drier, does just that, it dries out the little bit of moisture that was missed during vacuum.

It filters catch everything. Then how do pistons, and screens before metering devices get clogged?

[coolperfect]

What about acid removal and clean up of oil in the system and the system as a hole and you guys still have not answered the question is it ok to heat the oil to 1500f

[hvaclover]

What about acid removal and clean up of oil in the system and the system as a hole and you guys still have not answered the question is it ok to heat the oil to 1500f

If you can heat oil 1500*F than it's going to shoot out your leak like a flame thrower.

You can't seal a leak with oil present

[coolperfect]

I dont know about you but I was always told oil travels with the gas in our units

[beenthere]

The amount of oil that travels with the refrigerant, under normal circumstances, shouldn't be enough to hinder brazing. When in doubt, blow the line out first.

[hvaclover]

I agree.

Your question made me think you had oil at the braze point.
If conditions call for it a good flushing is called for to clean any contamanits that might be left.

[coolperfect]

The question is still at hand it not ok to braze with no nitro purge but in an existing unit with oil and freon at 0psi in the system we heat it to1500f we all do it all the time












/

[jrbenny]

The question was answered two posts above yours.

Yes, it's okay braze with some oil in the line. If you think there's too much, then flush the area.

Yes, you need to flow nitrogen while brazing. You can not control the flame enough to prevent crap from forming inside the pipe.

[hvaclover]

The question was answered two posts above yours.

Yes, it's okay braze with some oil in the line. If you think there's too much, then flush the area.

Yes, you need to flow nitrogen while brazing. You can not control the flame enough to prevent crap from forming inside the pipe.

BET ME!

[coolperfect]

I did not see any answer as to the break down of oil and freon when heated to brazing temp please let me know how we could flush an existing unit with out doing more damage than good

[jrbenny]

BET ME!
I've seen guys try. Guys that have been doing it for a long time trying get certified to do O2 system brazing.

It takes N2.

[tirednow]

hopefully everybody is talking about brazing as oxy-acetelyne vs air-acetelyne. my supervisor taught at the local abc school and did a demonstration on the difference and with and without nitrogen. of the 10 guys in the trade taking the class only one had used nitrogen during the brazing process, but not everytime. some of the other guys were installing systems in tract houses and were on a time table for instal. every class i've been in drove home the need of using nitrogen while oxy-acetelyne to braze. thats how i do it but just my 2 cents:)

[hvaclover]

I've seen guys try. Guys that have been doing it for a long time trying get certified to do O2 system brazing.

It takes N2.

What ever works for JR.

What's nice about already having made your nut is you don't have to prove nothing to nobody and it don't matter if somebody don't believe you.

I'm cool with what I do. Could I do your job? Probably not.

Could you run my gig? Same answer as above.

I'll leave you to ponder why.