ReplyOriginally Posted by Grayline
I do - I do.
Easy to hook up and cheap insurance.
It takes very little nitrogen (especially with a flow meter- see attachment) to ensure you have no debris inside the line.
Professional Member
I'm trying to convince one of my guys that Nitrogen is not used for every single weld.if we pump down a system to swap a solenoid or a txv you don't have to flow nitrogen thru it. How many old schoolers out there even use nitrogen to weld?
Global Moderator
Easy to hook up and cheap insurance.
It takes very little nitrogen (especially with a flow meter- see attachment) to ensure you have no debris inside the line.
Instead of learning the tricks of the trade, learn the trade.
Professional Member*
Why wouldn't you flow nitrogen?
The nitrogen displaces oxygen and prevents oxidation of the inside piping.
I use nitrogen for any and all brazing I perform. TXV's, Reversing Valves, etc all have small mechanical parts that can easily clog or fail due to particulate from oxidation in the system.
Back to my first question, Why wouldn't you flow nitrogen?
Professional Member*
Flow nitrogen during every braze, every time.
Professional Member*
Need to hook it up anyways very soon after the fact to leak test the new connections. Why not spend a few moments and hook it up just before you the brazing starts.
Professional Member*
I'm currently on a project where I'm brazing lots of 1-5/8 and 3-1/8 pipe.
If I didn't use nitrogen on even of of those 3" fittings I'd have a fistful of oxide, and a plugged dryer on startup.
We've gone through 8 nitro tanks, but it must be done!
Braze a couple joints and then cut them open, you'll see why!
Professional Member*
The same "old schoolers" that don't bother carrying a vacuum pump or don't believe or understand what a micron gauge is. These same old schoolers usually have a good tech following behind them cleaning up their messes when their "hurry up and get it done" work fails.
Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.
Professional Member
Maybe I didn't explain my Situation ,We do use nitrogen on all welds major installs,swaps,piping,etc just when I do a pumpdown and quick swap of a solonoid or weld over a rub leak.
if you only have an inch of welded surface its not gonna hurt to miss the hookup.. All others.... Compressor installs,Pipe-ins,major repairs etc.
Professional Member*
Yes, it will hurt. Even a small braze (not weld) will create oxidation.
Professional Member*
Always, even after 25 years
Professional Member
Always. It only gets worse (oxidation) with POE oil.
Professional Member*
Do a test to see who is correct. Make up a couple small copper loops and braze one with nitro flowing and the other with out. Then cut them open and see what you see.
Professional Member
Now that is just a pile of steaming BS. To label an entire generation of hard working "do it by the book" mechanics in such a fashion proves one thing to me. You have no idea what you are talking about. Are there hack mechanics? Sure there are and they come in ALL ages.
Professional Member*
You really do not even have to cut them open. Braze a coupling into two sections of pipe, then hold vertical and bang on a table with paper under it. Lots of flaky 'POO' will come out. Do you really want that stuff in your TXV or RV or compressor oil? And do you really want your customers to spread the work you do sloppy work when their unit fails WAAAAY before their neighbor's unit fails?
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Professional Member*
What is the acceptable quantity of abrasive material in the compressors oil sump?
Professional Member*
Dude, I'm on your side....
Professional Member
I have been in the field for many years, far from a hack and have brazed small diameter joints and quick repairs without nitrogen for years. I never recall a call back from a blockage or issues due to carbon from brazing and know that many of the small tonnage systems that I have installed are still working to this day with original components. But yes I used it when ever I have multiple joints or large joints. Those systems contained mineral oil though. The new oils have changed the way I think about everything I do.
Professional Member*
Since you have to get the nitrogen out to pressure test the system anyway, I don't understand some peoples resistance to purging with nitrogen...
Professional Member*
All I have to add is one simple common phrase.....better safe than sorry.
Professional Member
i use nitrogen each time. can you get away with it sometimes? sure. but why wouldn't you use tehniques that make things last 50 years instead of 'good enough' that only lasts 5-10?
"Right" is not the same as "Wise".
Don't step on my favorite part of the Constitution just to point out your favorite part.
Just because you can measure it, doesn't mean it is important. Just because you can't measure it, doesn't mean it isn't important.
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