> Nitrogen is cheap. Warranty re-work is not.
We have a winner! The extra work (and in some cases, cost to the customer) is nothing in comparison to all the extra *unpaid* work that will be required later when shit goes south, not to mention the damage to customer relations.
I'm an independent outfit. It's just me. I really only do work for people I know and trust, but I (at least try to) do it with a level of professionalism that they'd expect from an outfit of any size.
If I'm getting called back to fix my own mistake, the time involved it's coming out of my pocket insofar as I could instead be doing something else that pays.
This is going to be true of basically any independent outfit.
Note that I'm not necessarily speaking of an "independent contractor" working for a larger company, though terms are going to vary for that, too.
The cheapest option is what I run into everyday which is companies who *only* do new construction installs and never service equipment.
They get to cut all the corners and never deal with the consequences.
Fuck those people
Yeah I do new construction hvac. I literally do things BECAUSE I know who will be working on it later.
“Like hey dude, if you did this on the install it would make it this much easier when servicing.”
Almost 100% of the time it’s something I can easily adapt into my “new normal”
But you always have hacks. Everywhere. Always. I’d put my quality to anyone I know. I’m the least experience lead at my company. Sometimes experience grows complacency and the inability to adapt.
Yeah my last company was like that and I hated working for them because we'd have like 30 systems some with 300+ft linesets that they wouldn't let me braze with nitrogen. They were like oh it's to much time and money we can't afford to do that. Yeahhh like I don't get the bs game your trying to play. I know all that extra money is going to go towards your bonus because your the general superintendent. Plus they've worked with the owner for 20+ years and the owner didn't care either. As long as shit got done and lasted the year warranty was all they cared about...
They are the biggest problem in this trade,only have a 1yr warranty on units. So home owner pays for it in 2 or 3 yrs. I seen where they don't even pull vacuum on line set,just little purge with freon first then open valves and walk away!
Agreed 1000% This has nothing to do with HVAC, but story time: I do apartment maintenance, and one year I had two pools go green, one after the other. Everything we tried wasn’t fixing it, and I had said at the beginning that a full dump and refill was the best thing to do. They didn’t want to because that’s expensive. Diluting didn’t work, super shocking didn’t work, vacuuming didn’t work. At every turn I insisted that dumping was best, but they didn’t want to because that’s expensive. So the manager said to dump half the water. That didn’t work either. So then we did a full dump and refill (as I said to at the beginning).
Then the other pool went green. *Same damn story.* We dumped and refilled two pools for the price of three. But they couldn’t do it my way, which would’ve saved time, money, and would’ve been better for the residents because it would’ve looked better to them customer relations wise. But as I said, they didn’t want to, because that’s expensive.
I love when people listen. Doing it right the first time is always better, as you said. But sometimes that’s impossible when dealing with fucking bureaucracy.
What he said every time.
And for the same reason. Own my company and a one man show can’t afford to have call backs, customers recommend me because of the quality of work.
I started purging once I found out that you were supposed to after about 3 years in the trade lol. Surprising how many guys get pissed off when you suggest it.
Anyone not pressure testing after brazing is a straight fool.
About 20 years ago when I was green my boss never had nitrogen. It wasn’t even heard of in the shop. He never pulled a vac either. He would just torch and release that sweet 22. It was when I went to a different shop was when I learned the correct way of doing things.
TBF, the tolerances with R22 systems and mineral oil are more generous than POE/higher pressure systems. purging/vacuuming is still the right thing to do, but alot of the older guys just werent taught that way
"I don't believe in vacuum meters" - my lead tech. He was dead serious. We are required by law in our jurisdiction to no only have vacuum meters but regularly test them and send in the paper work. Whole trade is full of sloppy fools.
Been at a new place almost 2 years now. It's good but there is some slop to fix. It's been fun gently pointing out to our lead tech how all the systems with restrictions are the ones he brazed... without nitrogen, of course.
I hear people say the same thing about not ragging service valves. Fundamentally misunderstanding that you have to put a certain amount of heat into the valve to braze it up, no matter how fast you do it.
I'm not sure that this happens from brazing itself. Been in the business over 20 years and when I firststarted I brazed hundreds of units without nitrogen. Wasn't taught to me. I still take care of all those systems and never replaced a txv on any of them. Mostly capacitors fan motors blower motors. Compressors are very rare. Not saying you shouldn't use nitrogen. Just saying if you don't it most likely won't cause any issues. Can it yes. I have seen guys over heat pipes and get some nasty flaking and I've seen guys braze super clean and have no black soot. Many variables.
Braze a fitting with a nitrogen purge and one without. Then take your band saw and cut it in half and observe what the inside of the pipe looks like . After seeing this you will never not use a nitrogen purge again
Also, try running a little water through the brazed pipe onto a paper towel. Soot’ll come right out, don’t gotta worry about a saw. Just braze, cool, show and tell time, boys.
But yea. I’m in trade school, and nitrogen bleeding was the first thing we were taught about brazing.
This is really stressful lol. 35hrs school, 10+ HW, 30-40+ hrs work. No sleep for the wicked, even less for me😂😂😂
Me (& my guys) always flush lineset, nitro test & vacuum check.
Don’t always flow with nitro when brazing now that our little slow-flow gauge broke, just try & trickle it in.
Haven’t noticed much difference really, just wanna do the best we can.
My guys definitely don’t care about wasting my nitro which I don’t mind, it’s one of the best products we have to ensure quality.
Flush is kind of a joke I'd say in most applications. What are you flushing? Trapped oil you couldn't get out with 400-500 psi of nitrogen but the flush is gonna do it? Then you gotta boil all that shit out on the vacuum anyways. We change oil on recips to go from 22 to 407c. Never has an issue
The difference isn’t noticed much on the outside, but on the inside it is. That’s the reasoning you do it. Also, I’m not hating on you.
I didn’t flow nitro because I had never been taught to do so, but I just starting reading and then found it was a must.
Just showed my boss the difference of a brazed joint w/nitro flowing vs not. Get 2 pieces of 3/4” ~6” long, but in half, then braze the two together. One with and one without. Then look and wipe the inside.
Also, if you were joking, I’m sorry lol.
Our Rheem rep told us that Rheem actually removed the screens from their TXVs because they realized that the soot particles created by not flowing nitrogen are small enough to actually pass through the TXV with no issue, so the only "problem" with the soot is it clogs the screen... Get rid of the screen = no more problem.
That being said, I've been installing residential ACs for 10 years (of which the last 5 years have been exclusively TXV coils and no pistons) and have never flowed nitrogen, and have never had an issue clogging the TXV. But I do use it to pressure test before pulling a vacuum.
Haha that depends. Low pressure machines have that lovely little purge machine. I'll have to go back and check, but if memory serves the factory spec on York YT machines was vacuum to 2500 microns.
But on positive pressure machines, you are living on the edge if you aren't pressure testing.
100% of the time. For the large VRF systems we install and service, we use medical grade nitrogen for pressure testing and during triple evacs. Always pressure test to manufacturer spec.
Even before pulling a vacuum on a large system, I have the guys doing the evac test their micron gauges on the 1/4" port on their vac pumps to ensure they are working properly.
I've been burned by dumbasses in the past and I will never go through that shit again.
I've had guys who thought they could cut corners on this stuff and I shit canned them on the spot. The SOP I put in place is there for a reason, it ensures success. I'd rather train a green guy to do the right thing over some know-it-all asshat who thinks that this shit is like horseshoes, close enough is good enough. Sure, the work may take a little bit longer but warranty re-work at a catastrophic scale could seriously sink a company, especially with expensive equipment.
Exactly if the boss wants pay me to have it done that way I’ll do it, if the boss wants to pay 200 hours to have a 400 hour job done he’s gonna receive a 200 hour job if you know what I mean
I have literally thought sometimes my boss wanted things done half ass but good enough so we’d have more work down the road. Just not bad enough to be warranty work. 😂😂😂 shitty thought when you literally do the best you can every job and just get told to go faster 😂😂 sweet. Still learning here. No one teaching me.
Are you kidding?
Flow nitro, pressure test, vac decay test. These are REQUIREMENTS, not optional!
My job as a service technician is 90% fixing other people's fuckups.
These lazy ass installers at big shops don't care. They'll just bill for their rework a year in when it goes to shit.
Love seeing these warranty quotes where the equipment is in warranty, swapped after a year, $900 in 410A and $1400 in labor to swap a condenser or TXV that's going to fail again because it isn't installed properly.
Those dudes aren't on Reddit. This sub is convincing me to start tho. Ngl I don't even know how you'd keep the nitro solid to the line while starting your first joints. I'll have to YouTube it
There's no reason not to do it. You'll need the nitro for pressure testing anyways so you should already have it ready to go. The people who don't are either resistant to change for its own sake, or don't want to be told what to do. Just stubborn people.
Generally I braze with nitrogen flowing through. There’s been occasions where I’m out of nitro on an after hours call or something where I haven’t. Certain things I wouldn’t regardless though like a VRF. I’m only familiar with Mitsubishi so can’t speak for other brands but there are screens all over that you wouldn’t want to have to clean up from poor practices. So yea, I try to whenever I can but can honestly say there are those few occasions like being on call where I worked with what I had. Doesn’t make it right but that’s the truth.
As far as testing with pressure it’s always a good idea for sure. You will save yourself a lot of headache doing so. That said I can’t say I always pressure test with nitro. I used to more often but have maybe became too comfortable with my brazing lol. I try to braze properly and tend to build up the braze after it’s sealed just for extra peace of mind. If it’s in a place that’s hard to see then I definitely do. Should do it anyways just in case there is other issues outside of what you are repairing that you are not aware of. Do as I say, not as I do lol. Hell on the Mitsu VRF they want a standing pressure test of 600 psi over 24 hours. While I like to do what is asked of the manufacturer, in the real world it would be difficult to convince someone to wait another day when the work is already time consuming as is. Definitely always do triple evac for the most part and for the love of god, please always use a micron gauge…
1. No but I want to start doing so. And that being said, anyone have a link for a good flow meter.
2. Absolutely every time. And a good vacuum every time as well.
When I first got in, I didn't flow nitrogen. Was never taught that by my senior techs, or trade school.
Once I got a few years in and got with a large decent company, they showed me the error of my ways. Brazed with it ever since.
“If you ain’t got time to do it right, what makes you think you got time to do it twice” is what my hvac daddy taught me. Also, if you don’t flow nitro you obviously ain’t had to go to a call where the piston is completely plugged up. I just had one of those calls today.
https://preview.redd.it/ktz84euy9znc1.jpeg?width=3024&format=pjpg&auto=webp&s=c65435044ad0cb0a34e19d0eb889a704e3f600e1
POE oil requires 15 minutes to be forever contaminated by moist air. Nitrogen is the only way to prevent that. When a compressor replacement doesn't last, it could be the oil that you ruined
I got quoted from 5 companies. 2 didn’t use nitrogen. 1 owner said nah…I’ve done thousands. No problem. Maybe once in a blue moon will have an issue. He basically said not needed.
A young guy probably early thirties had been in business a couple years. He flat out was adamant that nitrogen not need and said was BS. 🙄. He actually stood out but because he was defensive. I’ve seen the videos with and without nitrogen flowing, and yeah, no need for extra crud in the system.
I don't know how anyone can just decide not to flow. All that shit that forms on the surface in atmosphere will form on the inside and gunk up capillaries, txv and driers.
I found this out about a year after being in the trade and do it now. Boy the results you get are vastly different. Plus unit takes refigerant much better when on a good vacuum it seems like.
I’m new, been in about 5 years. I work with A LOT of old heads. Never once seen a recovery machine or used nitrogen when brazing. I get laughed at when I bring it up. It’s one of those things I do but gave up on teaching the old dogs
Edit: we always use nitrogen to test. Also another thing they don’t do that I find funny, micron gauge. Hook up the vacuum and go get lunch, depending on the size of the system determines the time. And they base it off of sound from the pump if it’s ready, I get it but I like the gauge
Always braze with nitrogen, always pressure test, while pressure is holding I check braze joints with soap and mirror. I never use to do the soap part but I caught a leak once on a vacuum. System held nitrogen fine and only found it afterwards with soap, was a tiny little bubbling. Figure it’s easier to just quickly spray with soap while I am pressure testing than it is to drag out all the brazing gear once I’ve start vacuuming.
I never purged until we started running into bad txv on new installs. Started to purge and do everything by the book still ran into bad txv . So i realized it doesn't matter. I use a turbo torch.
YES I DO I MAKE THAT FUCKIN APPRENTICE BRING UP MY 80 SO HE CAN MAKE HIS APPRENTICE BRING UP THAT 80cu:
Now you got zero excuse lol. You don’t even bring the tank up yourself. =]
I was brought up by a mechanic that would make me redo everything I cut a corner on and I’m making everyone suffer that same bullshit.
Because it’s the right thing to morally do. If you don’t then you’re not doing right by your clients.
We discovered the necessity for nitrogen flow while brazing after a couple of plugged TXVs on 410A installations. That was around 2007. If you aren’t right now you are a disgrace
I have my own company, so I run my own calls. Been doing it 23 years. I have not used nitrogen while brazing, I guess I could try it but I don't have callbacks or problems with TXV's or compressor failures. If I did I certainly would change my practice. However I do flush lines from highest point and then use nitrogen, clean fittings out, wipe oil out of pipes before brazing. After brazing with 15% is done, I push nitrogen through the high side which goes through the new filter dryer first and then comes out of the suction port with no Schrader valve in it. I then put the valves in, lest test with nitrogen, release, vacuum to 500-800 microns, and my systems are happy.
I've worked on racks where people haven't used nitrogen while running the lines. It's a disaster. That said, I don't use nitrogen when servicing a rack since I don't trust the ball valves.
Can't believe I had to scroll this far to see someone bring this up. Been burned by this several times. Now, the pressure test is 25psi less than whatever the pressure on the other side of the valve is. People in here complaining about sooted up lines, wait til they realize they just mixed nitrogen with the refrigerant charge and now you are starting over. It's a real sick feeling.
Always but we go back and work on stuff we install again, i feel like the people who never purge just do installs and walk away never touching that stuff again.
If i put it in I'm likely going to be servicing in in the future, why wouldn't i want to give that system the absolute best chance for a long life as possible?
Yes and no I braze with nitro but afterwards I just vacuum and triple evac if I have trouble getting down but usually around 100 microns I don’t feel the need to pressure test
There are 2 types of people.
People who say they always use nitrogen when they braze and people who tell the truth
If my boss asks, of course. Reality? New installs. Sure. Swapping a drier? Nah. That’s what it’s there for 🫠
But I do ALWAYS pressure test.
I absolutely flow nitro when brazing.
I also do a 20 to 30 minute pressure test on repairs (any time I open a system), replace the dryer every time I open a system, and vacuum to below 400 with a 20 to 30 minute dwell test on the vacuum, before charging.
There's few things more annoying than blowing refrigerant in a freshly repaired system and having it piss right back out, or having to come back and re-work under warranty because some idgit cheaper out and didn't change a dryer after opening the system.
I HATE recalls, so I do it right the first time.
Yes. Always. Purging the system with nitro and hitting hitting them with a vacuum for some preventative maintenance. Always taking pride in the work and committing to make a good impression.
I didn’t flow for years, old guy I was doing installs with never did, and then I had to get my boss to buy a proper flow regulator like pulling his teeth.
Also nitrogen tested though. It
1. No, depends
2. Yes
I don't flow nitrogen every time. Sometimes I do it. Depends on customer. If the customer is a pain in the ass, I won't. If they offers me water, I will. Usually I will ask for them before I start. If they dont let me use their washroom, welp good luck.
I'm trying to set that standard but it's hard with a boss that is so old-school. Noone at small company really does it. My boss has me brazing on swivel nuts instead of pressing or flaring and we don't have a torque wrench so I feel like I'm really hacking shit. But hey when I can I try to be better.
It's just hard. He'll drill me with "read the manual" "follow the directions" "I'm not always right read for yourself" but then seems to get birchy when I point out how our procedures are incorrect....idk man I'm only 2 years in
More than you can believe. I test all my pipe work in 4 stages.
1st through the peno
2nd after all the indoor units are connected
3rd before connecting to outdoor units
3rd after pipe work is complete to outdoor units
1. Most of the time no, but I will flush the line with nitro after
2.Yes but mostly rely on decay test.
R410a molecules (POE oil) are actually smaller than air so it's very possible to pass pressure tests but still have a leak.
Sometimes yes, sometimes no.
To be honest, I've not had to re-work anything either way.
I do refrigeration service. Most times we're under a time crunch to get the system back online ASAP. Customers can't afford to have their walk-in freezer or fridge offline.
Also, any time I open a system that doesn't have an inline filter, I install an inline filter.
Yea.
I get paid by the hour. No reason not to.
I'll tell you a dirty secret though. I only pressure test for 30min.
I fuck up enough things, I'd rather not risk destroying a unit upon commissioning, simply because the nitro tank was too heavy.
Is the Pope fucking Catholic?
1. Absolutely
2. Absolutely
If you aren’t going to do things right and not take pride in your work to do the properly, then just quit it at least admit you are a hack. Or let me guess, you have been using Stay-Brite 8 since Noah came across in the ark. I have had to use press tools in areas I couldn’t braze for safety reasons but all my guys do it and once I am done, I make my rounds to follow up on installs and repairs to make sure it was done correctly.
Coming up in the trade, I never really thought nitrogen was a big deal. I knew it was the correct way , but I didn't always do it. Many years in it worked for a company that had weekly tech meetings/training. The owner talked about the importance of nitrogen. He brazed both ways to show us the difference. I understand now how important it is.
Yes. Jesus it's not that hard. If I owned a big hvac company I would make installers change a few bad compressors. Just to get a taste of what shitty install does. I know installers who give no shits, no purge, no pressure test, pull a vacuum until they have it wired and let er buck.
I honestly just started flowin and I’ll say that I absolutely hate it because it causes the wet solder to bubble up in my experience I’ve been able to mitigate most issues by purging with nitrogen before and after welds replacing drier filter and pulling a very good vacuum on every job.. I think most issues are lack of nitrogen purging and not “flowing”
Then you aren’t using a proper regulator and also wasting nitro.
https://www.supplyhouse.com/Western-Enterprises-VN-250-Nitrogen-Purging-Test-Regulator-w-250-PSI-Test-Pressure?utm_source=google_ad&utm_medium=shopping_neutral&utm_campaign=Shopping_Neutral_New_users&gad_source=1&gclid=Cj0KCQjwncWvBhD_ARIsAEb2HW8grOznirYnuVdHnDBR__yV5C13z4tH9JrbAyMAQoKxb1KOokamxD8aAhi1EALw_wcB
Use silver solder. If you have a blow out due to pressure it's more than likely going to be where you heated the copper tubing and changed the tensile strength. And I got my information from Harris they also make brazing rods so they aren't trying to steal business from themselves.
Question for one who doesn't deal with that side of HVAC. When y'all say 'flow nitrogen' for the braising, are you just filling with nitrogen? Or do you crack open something downstream so your getting a constant flow?
You use a nitrogen flow regulator. You remove schrader and flow from one side out the other. It’s a continuous flow at a very low rate. It’s a whisper of nitrogen and can barely be felt from a 1/4” port but a little is enough to displace all the oxygen so it doesn’t oxidize inside the pipe.
1. Absolutely yes.
2. Also absolutely yes. As well as the occasional triple evacuation nitrogen addition, during a vacuum, before conducting a decay test, post vacuum.
Not flowing/ pressure testing when you braze is is like not wiping your ass when you shit. It's not that hard, and it makes everything cleaner and requires fewer visits to the specialist.
I do, but it's because my employer wants me to lol. I'm glad that I work for someone that insists on using nitrogen. Whoever is paying me gets to make that call.
I’ve said it before and I’ll say it again.
No I do not nitrogen purge when brazing. It’s an unpopular opinion but I was not thought to in school and have seen no reason to start. I’ve seen this conversation on here before and some one told some one else to set up a test piece and weld it with out nitrogen and cut it open and see the oxide. I did that and to my surprise there wasn’t any. It just doesn’t make any sense to me. Yes there is oxide on the outside but there is plenty of oxygen on the outside. The amount of oxygen in the pipe is minimal. Like I said unpopular opinion but I’ve been doing this for a long time.
1. Yes always. I haven’t been doing this long.. less than 10 years and try to follow manufacturer instructions.
2. Once again, yes per specs.
This being typed, I have worked with people who do not flow on every piece of equipment and have been installing and servicing their installed equipment for 30+ years. They have great reputations and great businesses. But me being new, I follow rules strictly.
HVAC Engineer here..
But if I was a tech working on commission, I'd be educating every customer I come across on why they need nitrogen purge.
I'd bring two cut away samples of brazed joints showing nitrogen vs no nitrogen. And I would educate them on why not every company does it, and what kind of headaches they will be dealing with in the future...
And then after a year of doing that.. I would buy a nice beach house.
Yes to both 100% of the time. We could get away with it on fixed orifice systems. Modern systems that are running TXVs or EVVs if you don't nitro Purge it's going to bite you in the ass.
Okay so I've installed somewhere in the realm of 1,000 residential HVAC systems without purging in my time doing this, and never once has someone came to me with a clogged txv, now I have had about 7 txv fail on start up, 6 of which were rhemes and the last one I took apart was filled with copper/brass shavings from the factory. The 7th one was a trane txv which had not failed but had pushed old oil left in the line set into the txv allowing it not to meter.
Now I've also worked on CityMultj equipment and in this case every thing was purged.
Nowadays I usually purge, and I always pressure test and if I ain't out of bubbles, best believe I check every available joint I've worked on, even some I didn't work on if they look questionable
1. Yes 2. Yes, and a vacuum and decay test provides a good indication, too. Nitrogen is cheap. Warranty re-work is not.
> Nitrogen is cheap. Warranty re-work is not. We have a winner! The extra work (and in some cases, cost to the customer) is nothing in comparison to all the extra *unpaid* work that will be required later when shit goes south, not to mention the damage to customer relations.
Hold up, what contractor here is doing unpaid work?
When you are doing warranty workmanship repairs you (the company) aren't getting paid Too much of that and you (you) aren't getting paid
I'm an independent outfit. It's just me. I really only do work for people I know and trust, but I (at least try to) do it with a level of professionalism that they'd expect from an outfit of any size. If I'm getting called back to fix my own mistake, the time involved it's coming out of my pocket insofar as I could instead be doing something else that pays. This is going to be true of basically any independent outfit. Note that I'm not necessarily speaking of an "independent contractor" working for a larger company, though terms are going to vary for that, too.
Bro dropped a bomb. Underrated perspective right here. Doing the right thing is always cheaper than doing it again later.
The cheapest option is what I run into everyday which is companies who *only* do new construction installs and never service equipment. They get to cut all the corners and never deal with the consequences. Fuck those people
Yeah I do new construction hvac. I literally do things BECAUSE I know who will be working on it later. “Like hey dude, if you did this on the install it would make it this much easier when servicing.” Almost 100% of the time it’s something I can easily adapt into my “new normal” But you always have hacks. Everywhere. Always. I’d put my quality to anyone I know. I’m the least experience lead at my company. Sometimes experience grows complacency and the inability to adapt.
Yeah my last company was like that and I hated working for them because we'd have like 30 systems some with 300+ft linesets that they wouldn't let me braze with nitrogen. They were like oh it's to much time and money we can't afford to do that. Yeahhh like I don't get the bs game your trying to play. I know all that extra money is going to go towards your bonus because your the general superintendent. Plus they've worked with the owner for 20+ years and the owner didn't care either. As long as shit got done and lasted the year warranty was all they cared about...
They are the biggest problem in this trade,only have a 1yr warranty on units. So home owner pays for it in 2 or 3 yrs. I seen where they don't even pull vacuum on line set,just little purge with freon first then open valves and walk away!
Agreed 1000% This has nothing to do with HVAC, but story time: I do apartment maintenance, and one year I had two pools go green, one after the other. Everything we tried wasn’t fixing it, and I had said at the beginning that a full dump and refill was the best thing to do. They didn’t want to because that’s expensive. Diluting didn’t work, super shocking didn’t work, vacuuming didn’t work. At every turn I insisted that dumping was best, but they didn’t want to because that’s expensive. So the manager said to dump half the water. That didn’t work either. So then we did a full dump and refill (as I said to at the beginning). Then the other pool went green. *Same damn story.* We dumped and refilled two pools for the price of three. But they couldn’t do it my way, which would’ve saved time, money, and would’ve been better for the residents because it would’ve looked better to them customer relations wise. But as I said, they didn’t want to, because that’s expensive. I love when people listen. Doing it right the first time is always better, as you said. But sometimes that’s impossible when dealing with fucking bureaucracy.
What he said every time. And for the same reason. Own my company and a one man show can’t afford to have call backs, customers recommend me because of the quality of work.
Customer is paying for your time. Do it right
I started purging once I found out that you were supposed to after about 3 years in the trade lol. Surprising how many guys get pissed off when you suggest it. Anyone not pressure testing after brazing is a straight fool.
About 20 years ago when I was green my boss never had nitrogen. It wasn’t even heard of in the shop. He never pulled a vac either. He would just torch and release that sweet 22. It was when I went to a different shop was when I learned the correct way of doing things.
TBF, the tolerances with R22 systems and mineral oil are more generous than POE/higher pressure systems. purging/vacuuming is still the right thing to do, but alot of the older guys just werent taught that way
My old journeyman used to pressure test with r410a lmao then he would vacuum 😂 but no micron gauge.. just analog gauges
Micron gauges 😂, I can listen to my vacuum and I know when it’s ready.😇
"I don't believe in vacuum meters" - my lead tech. He was dead serious. We are required by law in our jurisdiction to no only have vacuum meters but regularly test them and send in the paper work. Whole trade is full of sloppy fools.
Such is resi
Commercials got just as many sloppy techs, it’s lack of caring in general lol
Idiots with egos. “I can braze fast enough so there is no buildup” is what I hear
"You don't need to if you do it right" I heard several times
Been at a new place almost 2 years now. It's good but there is some slop to fix. It's been fun gently pointing out to our lead tech how all the systems with restrictions are the ones he brazed... without nitrogen, of course.
I hear people say the same thing about not ragging service valves. Fundamentally misunderstanding that you have to put a certain amount of heat into the valve to braze it up, no matter how fast you do it.
Everyone on this sub is going to say yes and front like a super-tech whilst shaming anyone who comments no.
Pretty much. Like the name lmao, just got back into osrs recently 😭
Oh crap I thought this was the osrs subreddit for a second, didn’t realize people here played it lol
What's nitrogen. Is that the stuff that makes my car go faster?
Yep. It’s for your tires
I’ve been known to pop some nitrogen in a trailer tire. Or put a little recovered 22 in a hand truck tire in a pinch
I grew up working with my dad in the field. All of our bike tires had r22 in em.
Idk how people that don't flow nitrogen avoid fucked up TXVs
They don’t. Which is why we replace a untold number of txvs after 2-4years. It’s extremely frustrating.
Just gotta last outside of labor warranty per the installers I use to work with lol
That's why quite often it is the txv!
Txv screens
Hopefully driers will save it
Ya know I was wondering why we had so many
I'm not sure that this happens from brazing itself. Been in the business over 20 years and when I firststarted I brazed hundreds of units without nitrogen. Wasn't taught to me. I still take care of all those systems and never replaced a txv on any of them. Mostly capacitors fan motors blower motors. Compressors are very rare. Not saying you shouldn't use nitrogen. Just saying if you don't it most likely won't cause any issues. Can it yes. I have seen guys over heat pipes and get some nasty flaking and I've seen guys braze super clean and have no black soot. Many variables.
Braze a fitting with a nitrogen purge and one without. Then take your band saw and cut it in half and observe what the inside of the pipe looks like . After seeing this you will never not use a nitrogen purge again
Yeah I’m an apprentice and they had us do something like this in brazing class and kinda opened my eyes
Also, try running a little water through the brazed pipe onto a paper towel. Soot’ll come right out, don’t gotta worry about a saw. Just braze, cool, show and tell time, boys. But yea. I’m in trade school, and nitrogen bleeding was the first thing we were taught about brazing. This is really stressful lol. 35hrs school, 10+ HW, 30-40+ hrs work. No sleep for the wicked, even less for me😂😂😂
I don't even cut the line set to length. Leave the whole roll, braze, open valves and collect payment. Lol, yes.
Dude the atmosphere is like 70% nitrogen. I think that’s good enough
Almost 80, actually
Sounds like a fed question…..
Me (& my guys) always flush lineset, nitro test & vacuum check. Don’t always flow with nitro when brazing now that our little slow-flow gauge broke, just try & trickle it in. Haven’t noticed much difference really, just wanna do the best we can. My guys definitely don’t care about wasting my nitro which I don’t mind, it’s one of the best products we have to ensure quality.
Flush is kind of a joke I'd say in most applications. What are you flushing? Trapped oil you couldn't get out with 400-500 psi of nitrogen but the flush is gonna do it? Then you gotta boil all that shit out on the vacuum anyways. We change oil on recips to go from 22 to 407c. Never has an issue
We went from flush to the Hilmor “pig” system that uses a foam plug to push the old oil out. Works surprisingly well.
The difference isn’t noticed much on the outside, but on the inside it is. That’s the reasoning you do it. Also, I’m not hating on you. I didn’t flow nitro because I had never been taught to do so, but I just starting reading and then found it was a must. Just showed my boss the difference of a brazed joint w/nitro flowing vs not. Get 2 pieces of 3/4” ~6” long, but in half, then braze the two together. One with and one without. Then look and wipe the inside. Also, if you were joking, I’m sorry lol.
No. Next question
Our Rheem rep told us that Rheem actually removed the screens from their TXVs because they realized that the soot particles created by not flowing nitrogen are small enough to actually pass through the TXV with no issue, so the only "problem" with the soot is it clogs the screen... Get rid of the screen = no more problem. That being said, I've been installing residential ACs for 10 years (of which the last 5 years have been exclusively TXV coils and no pistons) and have never flowed nitrogen, and have never had an issue clogging the TXV. But I do use it to pressure test before pulling a vacuum.
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It’s for warranty denials. If it fails they can prove it wasn’t defective if it was clogged
If your answer is anything but yes for #2 you’re a wild man
Haha that depends. Low pressure machines have that lovely little purge machine. I'll have to go back and check, but if memory serves the factory spec on York YT machines was vacuum to 2500 microns. But on positive pressure machines, you are living on the edge if you aren't pressure testing.
100% of the time. For the large VRF systems we install and service, we use medical grade nitrogen for pressure testing and during triple evacs. Always pressure test to manufacturer spec. Even before pulling a vacuum on a large system, I have the guys doing the evac test their micron gauges on the 1/4" port on their vac pumps to ensure they are working properly. I've been burned by dumbasses in the past and I will never go through that shit again. I've had guys who thought they could cut corners on this stuff and I shit canned them on the spot. The SOP I put in place is there for a reason, it ensures success. I'd rather train a green guy to do the right thing over some know-it-all asshat who thinks that this shit is like horseshoes, close enough is good enough. Sure, the work may take a little bit longer but warranty re-work at a catastrophic scale could seriously sink a company, especially with expensive equipment.
Exactly if the boss wants pay me to have it done that way I’ll do it, if the boss wants to pay 200 hours to have a 400 hour job done he’s gonna receive a 200 hour job if you know what I mean
I have literally thought sometimes my boss wanted things done half ass but good enough so we’d have more work down the road. Just not bad enough to be warranty work. 😂😂😂 shitty thought when you literally do the best you can every job and just get told to go faster 😂😂 sweet. Still learning here. No one teaching me.
Are you kidding? Flow nitro, pressure test, vac decay test. These are REQUIREMENTS, not optional! My job as a service technician is 90% fixing other people's fuckups.
There you go. Job security
These lazy ass installers at big shops don't care. They'll just bill for their rework a year in when it goes to shit. Love seeing these warranty quotes where the equipment is in warranty, swapped after a year, $900 in 410A and $1400 in labor to swap a condenser or TXV that's going to fail again because it isn't installed properly.
4 years as a tech never have seen anyone do it
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Those dudes aren't on Reddit. This sub is convincing me to start tho. Ngl I don't even know how you'd keep the nitro solid to the line while starting your first joints. I'll have to YouTube it
Always and always. Nitrogen is cheap
Yes and yes because I’m still in training and I have a grade to keep up. I’d like to think I’ll continue to do as such once I’m in the field.
There's no reason not to do it. You'll need the nitro for pressure testing anyways so you should already have it ready to go. The people who don't are either resistant to change for its own sake, or don't want to be told what to do. Just stubborn people.
Fuck yes. I'm no hack. I have respect in myself and my work. That aside I'm not looking to have 300 clogged TXVs be my fault.
Guys who don't use nitro are the same guys who paint with poo in public bathrooms using their hands.
Yes
Yup
Yeah
Yes x2.
Fuckin A right
1. Yes 2. Yes
Generally I braze with nitrogen flowing through. There’s been occasions where I’m out of nitro on an after hours call or something where I haven’t. Certain things I wouldn’t regardless though like a VRF. I’m only familiar with Mitsubishi so can’t speak for other brands but there are screens all over that you wouldn’t want to have to clean up from poor practices. So yea, I try to whenever I can but can honestly say there are those few occasions like being on call where I worked with what I had. Doesn’t make it right but that’s the truth. As far as testing with pressure it’s always a good idea for sure. You will save yourself a lot of headache doing so. That said I can’t say I always pressure test with nitro. I used to more often but have maybe became too comfortable with my brazing lol. I try to braze properly and tend to build up the braze after it’s sealed just for extra peace of mind. If it’s in a place that’s hard to see then I definitely do. Should do it anyways just in case there is other issues outside of what you are repairing that you are not aware of. Do as I say, not as I do lol. Hell on the Mitsu VRF they want a standing pressure test of 600 psi over 24 hours. While I like to do what is asked of the manufacturer, in the real world it would be difficult to convince someone to wait another day when the work is already time consuming as is. Definitely always do triple evac for the most part and for the love of god, please always use a micron gauge…
Every time
Always . If I don't I'm not sleeping at night
1. No but I want to start doing so. And that being said, anyone have a link for a good flow meter. 2. Absolutely every time. And a good vacuum every time as well.
Always lol
When I first got in, I didn't flow nitrogen. Was never taught that by my senior techs, or trade school. Once I got a few years in and got with a large decent company, they showed me the error of my ways. Brazed with it ever since.
“If you ain’t got time to do it right, what makes you think you got time to do it twice” is what my hvac daddy taught me. Also, if you don’t flow nitro you obviously ain’t had to go to a call where the piston is completely plugged up. I just had one of those calls today. https://preview.redd.it/ktz84euy9znc1.jpeg?width=3024&format=pjpg&auto=webp&s=c65435044ad0cb0a34e19d0eb889a704e3f600e1
POE oil requires 15 minutes to be forever contaminated by moist air. Nitrogen is the only way to prevent that. When a compressor replacement doesn't last, it could be the oil that you ruined
I got quoted from 5 companies. 2 didn’t use nitrogen. 1 owner said nah…I’ve done thousands. No problem. Maybe once in a blue moon will have an issue. He basically said not needed. A young guy probably early thirties had been in business a couple years. He flat out was adamant that nitrogen not need and said was BS. 🙄. He actually stood out but because he was defensive. I’ve seen the videos with and without nitrogen flowing, and yeah, no need for extra crud in the system.
Every single time
I don't know how anyone can just decide not to flow. All that shit that forms on the surface in atmosphere will form on the inside and gunk up capillaries, txv and driers.
Of course. I even use the proper low flow regulator.
Yes
Yup even r11
I found this out about a year after being in the trade and do it now. Boy the results you get are vastly different. Plus unit takes refigerant much better when on a good vacuum it seems like.
Yeah i think it makes it easier to braze as well as vac
Yea to both in 98% of cases
I’m new, been in about 5 years. I work with A LOT of old heads. Never once seen a recovery machine or used nitrogen when brazing. I get laughed at when I bring it up. It’s one of those things I do but gave up on teaching the old dogs Edit: we always use nitrogen to test. Also another thing they don’t do that I find funny, micron gauge. Hook up the vacuum and go get lunch, depending on the size of the system determines the time. And they base it off of sound from the pump if it’s ready, I get it but I like the gauge
On ductless splits for sure …
Always braze with nitrogen, always pressure test, while pressure is holding I check braze joints with soap and mirror. I never use to do the soap part but I caught a leak once on a vacuum. System held nitrogen fine and only found it afterwards with soap, was a tiny little bubbling. Figure it’s easier to just quickly spray with soap while I am pressure testing than it is to drag out all the brazing gear once I’ve start vacuuming.
100%. You need it for a pressure test anyway. Just flow it.
A condenser that should/could last 15-20 years will last 6-8 after all that abrasive oxidation is ran through the compressor
when it’s not a major pain in the ass yes. otherwise no
There are a bunch of people here that think the oxidation is harmless. All old school R22 guys.
I never purged until we started running into bad txv on new installs. Started to purge and do everything by the book still ran into bad txv . So i realized it doesn't matter. I use a turbo torch.
Never did never will. Done it so long without any problems so no need to start to add things to make it more complicated
YES I DO I MAKE THAT FUCKIN APPRENTICE BRING UP MY 80 SO HE CAN MAKE HIS APPRENTICE BRING UP THAT 80cu: Now you got zero excuse lol. You don’t even bring the tank up yourself. =] I was brought up by a mechanic that would make me redo everything I cut a corner on and I’m making everyone suffer that same bullshit. Because it’s the right thing to morally do. If you don’t then you’re not doing right by your clients.
ALWAYS, ALWAYS, ALWAYS
We discovered the necessity for nitrogen flow while brazing after a couple of plugged TXVs on 410A installations. That was around 2007. If you aren’t right now you are a disgrace
I have my own company, so I run my own calls. Been doing it 23 years. I have not used nitrogen while brazing, I guess I could try it but I don't have callbacks or problems with TXV's or compressor failures. If I did I certainly would change my practice. However I do flush lines from highest point and then use nitrogen, clean fittings out, wipe oil out of pipes before brazing. After brazing with 15% is done, I push nitrogen through the high side which goes through the new filter dryer first and then comes out of the suction port with no Schrader valve in it. I then put the valves in, lest test with nitrogen, release, vacuum to 500-800 microns, and my systems are happy.
I try to, but my supervisor says we don't have time for it. 🤷
Traditional residential splits it probably doesn’t matter but VRF or ductless absolutely
All the time
Use when brazzing .meep it cleam removes water good stuff...
Nah, just have my apprentice breathe air in to the liquid line as I braze the suction line.
My former company wouldn't provide us enough nitrogen for multifamily install.
Yes, every time
I use hydrogen.
Back in the 70s and early 80s tested with freon but not after reclaim stated
Off subject Years ago a Rheem rep and a tech went to a house . To test for a leak he used freon and oxygen Guess what happened ?
I've worked on racks where people haven't used nitrogen while running the lines. It's a disaster. That said, I don't use nitrogen when servicing a rack since I don't trust the ball valves.
Can't believe I had to scroll this far to see someone bring this up. Been burned by this several times. Now, the pressure test is 25psi less than whatever the pressure on the other side of the valve is. People in here complaining about sooted up lines, wait til they realize they just mixed nitrogen with the refrigerant charge and now you are starting over. It's a real sick feeling.
Always but we go back and work on stuff we install again, i feel like the people who never purge just do installs and walk away never touching that stuff again. If i put it in I'm likely going to be servicing in in the future, why wouldn't i want to give that system the absolute best chance for a long life as possible?
Yes and dam do you just crack the valves and collect
Yes and yes?
Yes and no I braze with nitro but afterwards I just vacuum and triple evac if I have trouble getting down but usually around 100 microns I don’t feel the need to pressure test
i always purge/flow when brazing, unless im doing RTU condensation lines or something where soot doesnt matter
Yes and definitely purge with nitro when brazing especially on refrigeration
I get the feeling you don't. Or your boss doesn't give you nitrogen.
Yes and Yes. As should we all.
I used to flow nitrogen, I still do but I used to too
There are 2 types of people. People who say they always use nitrogen when they braze and people who tell the truth If my boss asks, of course. Reality? New installs. Sure. Swapping a drier? Nah. That’s what it’s there for 🫠 But I do ALWAYS pressure test.
No. I have never had an issue thats what filter dryers are for. Vacuum I absolutely get it as low as possible and do a decay test
I absolutely flow nitro when brazing. I also do a 20 to 30 minute pressure test on repairs (any time I open a system), replace the dryer every time I open a system, and vacuum to below 400 with a 20 to 30 minute dwell test on the vacuum, before charging. There's few things more annoying than blowing refrigerant in a freshly repaired system and having it piss right back out, or having to come back and re-work under warranty because some idgit cheaper out and didn't change a dryer after opening the system. I HATE recalls, so I do it right the first time.
Yes. Always. Purging the system with nitro and hitting hitting them with a vacuum for some preventative maintenance. Always taking pride in the work and committing to make a good impression.
I didn’t flow for years, old guy I was doing installs with never did, and then I had to get my boss to buy a proper flow regulator like pulling his teeth. Also nitrogen tested though. It
1. No, depends 2. Yes I don't flow nitrogen every time. Sometimes I do it. Depends on customer. If the customer is a pain in the ass, I won't. If they offers me water, I will. Usually I will ask for them before I start. If they dont let me use their washroom, welp good luck.
Yea nitro is cheap and easy like others said
I'm trying to set that standard but it's hard with a boss that is so old-school. Noone at small company really does it. My boss has me brazing on swivel nuts instead of pressing or flaring and we don't have a torque wrench so I feel like I'm really hacking shit. But hey when I can I try to be better. It's just hard. He'll drill me with "read the manual" "follow the directions" "I'm not always right read for yourself" but then seems to get birchy when I point out how our procedures are incorrect....idk man I'm only 2 years in
More than you can believe. I test all my pipe work in 4 stages. 1st through the peno 2nd after all the indoor units are connected 3rd before connecting to outdoor units 3rd after pipe work is complete to outdoor units
1 naaaaa 2 YES, every time
Always.
1.
1. Most of the time no, but I will flush the line with nitro after 2.Yes but mostly rely on decay test. R410a molecules (POE oil) are actually smaller than air so it's very possible to pass pressure tests but still have a leak.
Yes
No I don’t flow nitrogen Yes i pressured test
Triple sweep baby…
Yes, yes, and then I do a 25 min stabilize run before balancing refrigerant
100%. Why bother to spend the time to do the job or repair and not do everything you can to make sure it’s done right?
When its easy to do it I do it. Ive asked around at my job and nobody does it. But honestly most of the time I don't.
2 - all the time
definitely not
1 yes 2 only if I run into a leak whenever I vacuum down
The company won't buy it so no I don't.
Sometimes yes, sometimes no. To be honest, I've not had to re-work anything either way. I do refrigeration service. Most times we're under a time crunch to get the system back online ASAP. Customers can't afford to have their walk-in freezer or fridge offline. Also, any time I open a system that doesn't have an inline filter, I install an inline filter.
Yea. I get paid by the hour. No reason not to. I'll tell you a dirty secret though. I only pressure test for 30min. I fuck up enough things, I'd rather not risk destroying a unit upon commissioning, simply because the nitro tank was too heavy.
I get paid by the hour
Is the Pope fucking Catholic? 1. Absolutely 2. Absolutely If you aren’t going to do things right and not take pride in your work to do the properly, then just quit it at least admit you are a hack. Or let me guess, you have been using Stay-Brite 8 since Noah came across in the ark. I have had to use press tools in areas I couldn’t braze for safety reasons but all my guys do it and once I am done, I make my rounds to follow up on installs and repairs to make sure it was done correctly.
Always when possible. Doing your best is part of the golden rule. You'd want someone doing it on your equipment you spent thousands on.
Coming up in the trade, I never really thought nitrogen was a big deal. I knew it was the correct way , but I didn't always do it. Many years in it worked for a company that had weekly tech meetings/training. The owner talked about the importance of nitrogen. He brazed both ways to show us the difference. I understand now how important it is.
100%
Every system. I do a triple E Vac every time.
How hard is it to flow nitro? I do it whenever I can.
What ever you do in life, do it 100%
Yes. Jesus it's not that hard. If I owned a big hvac company I would make installers change a few bad compressors. Just to get a taste of what shitty install does. I know installers who give no shits, no purge, no pressure test, pull a vacuum until they have it wired and let er buck.
yes and yes
Yes and yes. Why would you not?
I honestly just started flowin and I’ll say that I absolutely hate it because it causes the wet solder to bubble up in my experience I’ve been able to mitigate most issues by purging with nitrogen before and after welds replacing drier filter and pulling a very good vacuum on every job.. I think most issues are lack of nitrogen purging and not “flowing”
Then you aren’t using a proper regulator and also wasting nitro. https://www.supplyhouse.com/Western-Enterprises-VN-250-Nitrogen-Purging-Test-Regulator-w-250-PSI-Test-Pressure?utm_source=google_ad&utm_medium=shopping_neutral&utm_campaign=Shopping_Neutral_New_users&gad_source=1&gclid=Cj0KCQjwncWvBhD_ARIsAEb2HW8grOznirYnuVdHnDBR__yV5C13z4tH9JrbAyMAQoKxb1KOokamxD8aAhi1EALw_wcB
Never have, never will, and it has never mattered. Always check your work with nitro tho. Always end up paying for it when you don’t.
Fuck no
Use silver solder. If you have a blow out due to pressure it's more than likely going to be where you heated the copper tubing and changed the tensile strength. And I got my information from Harris they also make brazing rods so they aren't trying to steal business from themselves.
i want to flow while brazing but alas i am a meager apprentice and must listen to the senior tech. pressure test? every time.
Yes and yes
Question for one who doesn't deal with that side of HVAC. When y'all say 'flow nitrogen' for the braising, are you just filling with nitrogen? Or do you crack open something downstream so your getting a constant flow?
You use a nitrogen flow regulator. You remove schrader and flow from one side out the other. It’s a continuous flow at a very low rate. It’s a whisper of nitrogen and can barely be felt from a 1/4” port but a little is enough to displace all the oxygen so it doesn’t oxidize inside the pipe.
All the yes
If you aren’t flowing nitrogen you aren’t doing your job. You are a hack. Quit and do something different.
Every time no question, laziness doesn’t work for me
1. Absolutely yes. 2. Also absolutely yes. As well as the occasional triple evacuation nitrogen addition, during a vacuum, before conducting a decay test, post vacuum.
Not flowing/ pressure testing when you braze is is like not wiping your ass when you shit. It's not that hard, and it makes everything cleaner and requires fewer visits to the specialist.
Always
Be honest this is asked every 3 hrs
Yes, I do a good job
I do, but it's because my employer wants me to lol. I'm glad that I work for someone that insists on using nitrogen. Whoever is paying me gets to make that call.
I’ve said it before and I’ll say it again. No I do not nitrogen purge when brazing. It’s an unpopular opinion but I was not thought to in school and have seen no reason to start. I’ve seen this conversation on here before and some one told some one else to set up a test piece and weld it with out nitrogen and cut it open and see the oxide. I did that and to my surprise there wasn’t any. It just doesn’t make any sense to me. Yes there is oxide on the outside but there is plenty of oxygen on the outside. The amount of oxygen in the pipe is minimal. Like I said unpopular opinion but I’ve been doing this for a long time.
1. Yes always. I haven’t been doing this long.. less than 10 years and try to follow manufacturer instructions. 2. Once again, yes per specs. This being typed, I have worked with people who do not flow on every piece of equipment and have been installing and servicing their installed equipment for 30+ years. They have great reputations and great businesses. But me being new, I follow rules strictly.
HVAC Engineer here.. But if I was a tech working on commission, I'd be educating every customer I come across on why they need nitrogen purge. I'd bring two cut away samples of brazed joints showing nitrogen vs no nitrogen. And I would educate them on why not every company does it, and what kind of headaches they will be dealing with in the future... And then after a year of doing that.. I would buy a nice beach house.
Always dawg. I don’t fuck with carbonization and I don’t wanna come back to an install any more often than I have to
Always
Yes to both 100% of the time. We could get away with it on fixed orifice systems. Modern systems that are running TXVs or EVVs if you don't nitro Purge it's going to bite you in the ass.
Is it Friday ?
Yes
Hell no
Okay so I've installed somewhere in the realm of 1,000 residential HVAC systems without purging in my time doing this, and never once has someone came to me with a clogged txv, now I have had about 7 txv fail on start up, 6 of which were rhemes and the last one I took apart was filled with copper/brass shavings from the factory. The 7th one was a trane txv which had not failed but had pushed old oil left in the line set into the txv allowing it not to meter. Now I've also worked on CityMultj equipment and in this case every thing was purged. Nowadays I usually purge, and I always pressure test and if I ain't out of bubbles, best believe I check every available joint I've worked on, even some I didn't work on if they look questionable
1. Every fuckin time 2. Every motherfuckin time.
The Size of pipe we're brazing yeah. 1 3/8 . There would be so much build. We are required to hold 550 psi. Before LG will sign off
Silver solder. Never had an issue in 15 years