Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.

Brazing without nitrogen?!

ChrisJ
ChrisJ Member Posts: 11,549
My boss had a split system installed yesterday and I noticed the guy was doing all of his brazing without flowing nitrogen. I asked him where his nitrogen was and he told me that is only used for pressure testing and is never used during brazing.



I'm a bit disgusted at this and am wondering how common of a practice this is?
Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
«1

Comments

  • bob_46
    bob_46 Member Posts: 813
    N2

    Chris, from my 40 years experience working for a number of contractors I would say N2 is the exception rather than the rule . If you question the boss they usually tell you "that's why

    they invented filters" ! The only jobs that used it consistently were medical gas jobs and chemical research .
    bob
  • ChrisJ
    ChrisJ Member Posts: 11,549
    Interesting

    Bob,



    Thanks for responding. This is the kind of feedback I'm interested in hearing because I only do this for a hobby so I don't know what goes on in the real world.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • RobG
    RobG Member Posts: 1,850
    Cost

    Nitrogen costs more than O2. End of story. I guess that's why god invented filters.





    I have a friend who owns a bar and has a long draw beer tap system. He has to use a nitrogen CO2 mixture to keep the beer from foaming (and wasting the nectar of the gods). It costs about twice what straight CO2 does, however that's still cheaper than wasting the beer. The almighty dollar wins every time.



    Rob
  • Techman
    Techman Member Posts: 2,144
    Brazing

    should be done using Nitrogen! You are right ChrisJ. Nitro is CHEAPER than FilterDriers, not using Nitro will eventually lead to a comp failure. Everywhere you see the oxidation marks on the outside of the tubing there will be matching oxidation/flacking on the inside of the copper tubing.



    Back in the day air was used to pressureize the keg of beer, the last 1/4 of the keg tasted way different than the 1st 3/4 of the keg. The CO2 left the beer to fill up the atmosphere of the keg, then C02 was used to pressureize the keg, but the last1/4 of the keg was usually over CO2'ed and foamed up the mug. Then NuCO2 was brought in and much less foaming thru out the entire keg. Almost good to the last drop, for beer lovers.
  • ChrisJ
    ChrisJ Member Posts: 11,549
    Cost

    I think it costs me $20 or $25 to have my 60cuft bottle filled. Seems fairly cheap to me.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • RobG
    RobG Member Posts: 1,850
    I wasn't

    I wasn't disagreeing with the nitrogen brazing issue (I don't do A/C except my own and only with the help of a friend who DOES do A/C). I do however braze piping for plumbing work and just use oxy/acet. I don't have to worry about compressors, I just unscrew aerators. However allot of companies don't care. The customer pays for the filter, when the compressor does give up the ghost they are going to call the guy who's sticker is on the unit, them. Then they will sell them a whole new system. Once again, the almighty dollar wins. Unfortunately it is the mantra of allot of service companies.



    Rob
  • Techman
    Techman Member Posts: 2,144
    Nitro.

    For ACR that Nitro has to be "dry" or you will be adding wetness into the refrig system.
  • Paul S_3
    Paul S_3 Member Posts: 1,257
    nitrogen and brazing

    When I worked for other contractors they never wanted me to braze with nitrogen, only to pressurize. On the other hand they had many problems with clogged TXV'S and failed compressors etc, that they had to go back(call backs) which cost money, now I have my own business all my techs and me and my partner ALWAYS braze with nitrogen purging through the line set, Johnstone sells a adapter especially for this purpose and a low psi regulator, I have very few call backs ,luckily.....Paul s
    ASM Mechanical Company
    Located in Staten Island NY
    Servicing all 5 boroughs of NYC.
    347-692-4777
    [email protected]
    ASMHVACNYC.COM
    https://heatinghelp.com/find-a-contractor/detail/asm-mechanical-company
  • Ironman
    Ironman Member Posts: 6,359
    A Slight Compromise

    I almost hate that word, but some circumstances warrant it.



    If it's a mini split system or multiple joints, then N2 should always be used. If it's just connecting the line set on each end (2 joints) with a properly sized filter/drier installed, then I don't see where there's enough oxidation produced to make a difference.



    Just MHO, but in 40+ years, I don't know of a compressor failure that I've had in less than 10 years of service from a unit. Electrical and other component failures which would cause a compressor failure being excepted. It may even be closer to 15 years. I'm very meticulous and a leak free system, a good vacuum and proper charging are more important than a MINOR amount of oxidation.



    Again, JMHO.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • ChrisJ
    ChrisJ Member Posts: 11,549
    Minor?

    Are you sure it's minor?



    http://youtu.be/3uP-eb8Zz08
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • gennady
    gennady Member Posts: 819
    edited July 2014
    nitrogen

    When we did ac installations, nitrogen was a must. Triple evacuation only dries up copper, and testing shows the leaks. But brazing without nitrogen is a shortcut to lower costs. Anyway i heard that some plumbers do not use primer on PVC joints. so I'm not surprised.
  • Ironman
    Ironman Member Posts: 6,359
    Video

    Nice video; and it makes the point of the need for using N2. I'm not disputing that, but please look at everything I said.



    I've worked on everything from 1000 ton centrifugals down to household refrigerators. I've seen a four inch suction line on a recip so full of carbon from a burnout that it filled 2 quart jars. What could not be removed by hand cleaning had to be left in for the driers to catch. They did just that and after the second change, remained clean.



    I've seen centrifugal burn outs so bad that after chemical cleaning, the driers still required multiple changes. But they did their job and the compressor ran fine for many years thereafter. Don't discount what the drier can do.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • jumper
    jumper Member Posts: 1,616
    this is why

    Packaged unitary and chillers are bought.Even in industrial & high technology environment management does want to get into refrigeration assembly.
  • Techman
    Techman Member Posts: 2,144
    edited July 2014
    Brazing.

    I agree with Ironman . Have done it , still do it and will continue to do it! Nice point ! But not on Minis . But, not what you do ChrisJ!
  • icesailor
    icesailor Member Posts: 7,265
    PVC Primer:

    Not only do some "plumbers" not use primer, they don't chamfer the edge of the pipe so the sharp edge doesn't wipe out the cement while going in to the socket.

    Some use purple cleaner. Some use purple cement. Some don't use cleaner at all but use purple cement. If you can't see the writing on the side of the pipe, disappear before it goes into the socket, it wasn't cleaned.
  • KC_Jones
    KC_Jones Member Posts: 4,649
    Off topic but...

    Ice you are hitting another nail on the head.  I have been through manufacturers training from Spears on proper PVC pipe joint assembly.  Some things I learned the "cleaner" doesn't just clean it is actually the solvent for the pipe and is part of the "welding" of the joint together.  In addition how many "plumbers" actually hold the joint together for the appropriate time?  On smaller pipe (less than 2") it's 2-5 minutes that the pipe needs to be held in position.  On larger pipe (2 1/2"-8") it's supposed to be held together for 30 minutes.  On DWV it probably isn't a big deal because of the lack of pressure, but on any pressurized pipe it can be.  The company I work for put us all through this training a while ago and it was a huge eye opener for all.  We discovered this was the cause of some leaking pipe on our units.  I have personally watched a joint back out 10 minutes after assembly due to pipe size and cure times.  Those sockets are tapered and will push the pipe back out.  We work in PVC as big as 16" that pipe needs to be clamped up and left for at least 2 hours to cure.  All these "recommendations" are of course just that.  The bottom line though if the manufacturers instructions aren't followed the warranty is void on the pipe and fitting.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • icesailor
    icesailor Member Posts: 7,265
    Paying Attention:

    You paid attention in class.

    When the windshield wipers on your vehicle won't "wipe" the rain away, why? Because the sharp rubber edge is rounded off by wear. I used a 12" 64 tooth carbide saw blade on my chop saw. A cut was so sharp that you could cut your finger on the cut-off. What happens when you don't chamfer the edge? It wipes the cement out like a new windshield wiper blade. Like the sharp edge scrapes the cement and softened PVC on the fitting.

    How many plumber's carry a PVC De-Burring tool in their bucket or bag? 4 Way files work well too. You get a rounded rasp and **** file on one side, and a flat rasp and **** file on the other.
  • TonyS
    TonyS Member Posts: 849
    I always use nitrogen

    Not using it would be the equivalent of tig welding without argon. What I have done to reduce my cost and time is I keep two 330cf tanks in the shop and fill a 20cf tank.

    I can only equalize the pressure but I get many fills before taking the 330 in for a refill.
  • unclejohn
    unclejohn Member Posts: 1,716
    AS far as I know

    Which ain't much on mini splits. You never braze it's all flare fittings. Also I've used nitro only once on a large refrig. piping job, well most of it anyway. Had the biggest bottle I could handle and still it would not last the day on big pipe.
  • Techman
    Techman Member Posts: 2,144
    Nitro

    That video was great!! Made its point!!! Nitro is needed!!!! Did that 35 years ago !!! How many times have you made a coupling ,that beautiful bright glowing red, that intense heat kinda way?. Can you FEEL it ? That's HOT!!! I was taught that the copper goes thru some kind of "change of composition" thing when "overheated" , and overheated makes "more" oxidation/flacking. than not glowing fittings.



    The "idea" of what is being done is demonstrated  superbly !!!!!!!!!!!!!!
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,215
    edited July 2014
    Copper (II) Oxide = CuO

    Interesting stuff, CuO

    It has been beat into my head that it is an abrasive and nitro should always be used. "Which I do, unless I'm in one of those unique situations that the books conveniently ignore." In fact, apparently CuO is used to polish optical equipment; cool.



    Then there is this paragraph that I barely understand. It makes some interesting points about CuO enhancing fluid viscosity and thermal transfer.

    1.1. Characteristics of CuO NPs

    CuO is the simplest member in the family of Cu compounds and exhibits a range of potential physical properties, such as high temperature superconductivity, electron correlation effects, and spin dynamics [15,16]. As a semiconducting compound with a monoclinic structure, CuO has attracted particular attentions in the field. It possesses useful photovoltaic and photoconductive properties because CuO crystal structures have a narrow band gap [17]. Besides the property, CuO NPs hold novel characteristics. CuO NPs can also improve fluid viscosity and enhance thermal conductivity, and these novel properties make them a potentially useful energy-saving material that can improve the effect of energy conversion [18]. CuO NPs have been applied in different areas, including gas sensors [19], catalysis [20], batteries [21], high temperature superconductors [22], solar energy conversion [23], and field emission emitters [22]. For industrial catalysis, CuO NPs may be able to replace noble metal catalysts for carbon monoxide oxidation [24], which would reduce production cost and improve the catalytic efficiency. The suspension has excellent thermal conductivity and can be used as a heat transfer fluid in machine tools [25]. CuO is much cheaper than silver oxide and can be mixed with polymers more easily to obtain composites with unique chemical and physical properties. Because they can reduce friction [26], and mend worn surfaces, CuO NPs are used as an additive in lubricants, polymers/plastics, and metallic coatings [27]. Moreover, the extremely high surface areas and unusual crystal morphologies endow CuO NPs with antimicrobial activity, and they dose-dependently inhibit



    Here is the whole article http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCIQFjAA&url=http%3A%2F%2Fwww.mdpi.com%2F1996-1944%2F5%2F12%2F2850%2Fpdf&ei=muXaU_TyJY6lyASb_oLYBg&usg=AFQjCNHsfETPS9nTYUK-fduYRHsSZNcUHA&sig2=KDklJ6vFhfRVMX49kp4lgg&bvm=bv.72197243,d.aWw



    Harvey

     

      
    Ramer Mechanical
    ramermechanical.com
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • KC_Jones
    KC_Jones Member Posts: 4,649
    Enjoying reading this

    Some of the conversations on this site are thoroughly enjoying.  I am enjoying the back and forth on this topic.  I have only brazed a handful of times in my life, most of my experience is welding so this has been very educational for me.  I am just a homeowner, but I do a lot of my own work so I always like hearing and learning about how things should be done.  I am not going to try brazing refrigeration lines anytime soon that is what I learned here.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • ChrisJ
    ChrisJ Member Posts: 11,549
    edited July 2014
    Amature

    Like I said, I'm only an amateur and do this as a hobby, but in my eyes if I'm willing to spend time and money to do it right, shouldn't a professional?



    I will admit, my wife was anything but happy when I started dumping money into the equipment to do this but it takes what it takes.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • bob_46
    bob_46 Member Posts: 813
    Juice

    Chris , what kind of "juice" are you going to put in that GE monitor dome?
    bob
  • ChrisJ
    ChrisJ Member Posts: 11,549
    edited August 2014
    Methyl formate

    Hi Bob,



    I used methyl formate as it is the original refrigerant used in the 1933-34 CA type monitor tops.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Techman
    Techman Member Posts: 2,144
    Nitro.

    ChrisJ ,do you have a P/T chart for methyl  formate?
  • ChrisJ
    ChrisJ Member Posts: 11,549
    P/T chart

    Hi Techman,



    Yes, I have two of them, one showing a curve compared to other refrigerants and this one. I'm attaching this one because I have it handy.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • earl burnermann
    earl burnermann Member Posts: 126
    Only once

    did I see a tech use nitrogen. Everyone at the company said he was too slow. But when he gave his notice they asked him to stay for the two weeks he offered. Everyone else that resigned was out the door immediately.

    On my job, If I'm there, we use nitrogen for brazing. The guy with me usually doesn't want to go the extra step, but we do.
    If the women don't find you handsome, they should at least find you handy!
  • earl burnermann
    earl burnermann Member Posts: 126
    edited August 2014
    double post

     sorry
    If the women don't find you handsome, they should at least find you handy!
  • radmix
    radmix Member Posts: 194
    Brazing

    All connections on Mini splits should be flared not brazed. the 1/4" line is so small the you could end up with a bead of brazing rod or solder in the line. 
  • ChrisJ
    ChrisJ Member Posts: 11,549
    1/4"

    I think a lot of the tubing I was brazing is 1/4" along with the tiny capillary tube.  If you're good you have nothing to worry about.



    But as you said, the connections are all flared anyway so no need to braze.  I do wonder how good a flare connection is vs brazed though?  I'm guessing it should be fine as long as it's tightened correctly?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Ironman
    Ironman Member Posts: 6,359
    Brazing on Mini Splits

    Not all manufacturers require flares on their mini splits. Did a training class on ECR minis a few weeks ago and they said brazing was okay as long as nitrogen was used.



    Did an LG 8 zone that someone else had started and all the separation wyes were brazed as that is what LG supplied with the units.



    Regarding flaring on mini splits: the thicker forged flare nuts that are supplied with the unit should be used. They are the only ones approved for 410a. Also, a flare torque wrench should be used in tightening. I double flare everything and have not had a leak on anything in 15+ years of doing it.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • radmix
    radmix Member Posts: 194
    Double Flair

    Does a double flair mean that you flair the same pipe twice
  • KC_Jones
    KC_Jones Member Posts: 4,649
    Sort of

    Basically a double flare makes the flare have double the tube wall thickness.  Here is a video showing how to do it.  This one is for brake lines, but it's the same for anything.  These types of flares reinforce the end for extremely high pressures (brakes systems can see thousands of PSI).



    http://www.youtube.com/watch?v=4fmF9mm3hsM
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • TonyS
    TonyS Member Posts: 849
    When installing ductless ac

    in second floor bedrooms on interior walls I will usually cut off the flare nuts on the indoor unit, swage, and braze longer stubs that will protrude above the attic floor. I usually do this in the shop with nitrogen then I braze one end shut and braze a schrader on the other and test. I refuse to bury a flare joint that I cant access.
  • radmix
    radmix Member Posts: 194
    Good Video

    Ive been using a flair tool made for R-410 A refrigerant. I can see in the video how the thickness of the pipe increases.
  • Ironman
    Ironman Member Posts: 6,359
    Double Flare

    The tube is essentially hemmed over and the inner portion acts somewhat like a metal gasket allowing a small cushioning effect.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • TonyS
    TonyS Member Posts: 849
    Who makes your flare block?

    I have one for smaller brake lines but I have not seen one for larger lines?
  • Ironman
    Ironman Member Posts: 6,359
    Flare tool

    Mine is Imperial Eastman, but the double flare dies didn't come with that tool - they were optional. I got them from Harbor Freight with a $10.00 Chinese tool. :) I threw the tool away and kept the dies since they were what I wanted. They are identical to those that come with the good flare tools.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • TonyS
    TonyS Member Posts: 849
    I also just found

    Rigid makes one also. Im going to have to give that a shot. I have a small one I do brake lines with but have never tried it with copper.

    Thanks
Sign In or Register to comment.

Welcome

It looks like you're new here. If you want to get involved, click one of these buttons!