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?
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?
Flow nitrogen during every braze, every time.
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.
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!
Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.
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.
Always, even after 25 years
Always. It only gets worse (oxidation) with POE oil.
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.
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.
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?
GA-HVAC-Tech
Your comfort, Your way, Everyday!
GA's basic rules of home heating and AC upgrades:
*Installation is more important than the brand of equipment
*The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
*The value of comfort, over the long term; leave economic choices behind!
Choose your contractor wisely!
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.
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...
All I have to add is one simple common phrase.....better safe than sorry.
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.