[Capz]

I never heard of oxygen free nitrogen. We use 99.999 nitrogen pumped from a cryogenic tank.

Maybe oxygen free nitrogen slightly less pure? Does it come from LIN (air separation)? Or does it come from swing absorb process?

The only real difference between industrial grade nitrogen and spec grade nitrogen here in the states is the paper trail. Spec grade is tested and documented when filled. ind grade is not.

 

[barbar]

We class OFN as higher purity, yes from LIN (not sure of the % sorry)

 

[Capz]

Interesting...never heard OFN terminology.

Here is an image of a fancy Pittsburgh Cup. Not what we used. Our tool, much more basic. A Pittsburgh Cup may have been a manufacture name rather than a trade name.

Slowly purge test vapor thru inside of the chamber pass the mirror with dry ice in center of cup. Watch for dew. Observe temp. read chart.

 

[barbar]

Interesting...never heard OFN terminology.

Here is an image of a fancy Pittsburgh Cup. Not what we used. Our tool, much more basic. A Pittsburgh Cup may have been a manufacture name rather than a trade name.

Slowly purge test vapor thru inside of the chamber pass the mirror with dry ice in center of cup. Watch for dew. Observe temp. read chart.

View attachment 378641

Where do think ASCO,s manufacturing plant is??

 

[Capz]

ASCO CARBON DIOXIDE LTD, Romanshorn / Switzerland, Tel. +41 71 466 80 80 / Fax +41 71 466 80 66, e-mail: info@ascoco2.com, www.ascoco2.com

 

[barbar]

ASCO CARBON DIOXIDE LTD, Romanshorn / Switzerland, Tel. +41 71 466 80 80 / Fax +41 71 466 80 66, e-mail: info@ascoco2.com, www.ascoco2.com

Na, just round the corner, Christchurch, New Zealand

 

[Capz]

Na, just round the corner, Christchurch, New Zealand

Cool, send us out a co2 dew point tester! Thanks.

 

[barbar]

Cool, send us out a co2 dew point tester! Thanks.

No problems, for

cccccccccccccccccccc.cccc.cc.c cash?

 

[jpsmith1cm]

co2 is inert at room temperature. But the question that needs answering, is at what temperature does it become reactive? I don't have the answer to this question. see pg12
http://www.lincolnelectric.com/assets/en_US/Products/literature/C4200.pdf

My background is with BOC Gases as a field service tech on medical, industrial & the food industry. Our trainers taught us not to use co2 for purging. This is what I go by. Commercial grade co2 is not a pure gas. The cylinder of co2 on your truck is likely a by-product of the oil & gas industry and other places unless you have spec gas. What's the moisture content in co2 vs nitrogen? I don't know. I'll keep using nitrogen from an Airgas cylinder. Or maybe I'll sweat some coupons with co2 purge for inspection and document the outcome for my own good.

And one more thing, go ahead and fill your refrig unit with co2 for pressure testing on a very cold day. Blow it out quick. What will happen to some of co2 inside the compressor? I guess a good vacuum will solve this issue but why bother using it in the first place? It's not a great gas for leak testing. Nitrogen is much lighter and a better gas for leak testing and easier to evacuate.

We aren't talking welding, friend, so that information, while interesting, isn't really pertinent to the discussion we're having about using CO2 to prevent oxidation within a copper line being heated to 12-1400 degrees F.

Please, do as you suggest and try a couple of joints with CO2 and post pictures showing us how different they are from one done with nitrogen.

I'll be very interested to see the difference.

In order for CO2 to flash-freeze to dry ice, you would have to have LIQUID CO2 in the system. Paying close attention to pressure/temperature relationship of CO2 would prevent that from happening.

 

[Grayline]

Why not just use Nitrogen? Its a known gas that has no effect by heat,does not hold or transfer h20
And is simple to aquire,regulate,use...
just sayin... why not use pure argon or Halon they both displace oxygen, and are odorless an contain no moisture.

 

[Phase Loss]

Not interested in what the book says...I want to hear about real life experience.

Has anyone ever ran into a system problem during service that you could 100% say was caused by brazing without flowing nitro/co2...whatever.

I've never once flowed nitrogen during service repairs, don't even pressure test. (my welds don't leak) :grin2:

Just braze it up, pull a vacuum, and get it going.

I've brazed in cap tubes, txv's, reversing valves, all kinds of valves, never had one fail to my knowledge.

I've only been in the trade 9 years, so maybe not enough time has passed to tell yet.

 

[jpsmith1cm]

Not interested in what the book says...I want to hear about real life experience.

Has anyone ever ran into a system problem during service that you could 100% say was caused by brazing without flowing nitro/co2...whatever.

I've never once flowed nitrogen during service repairs, don't even pressure test. (my welds don't leak) :grin2:

Just braze it up, pull a vacuum, and get it going.

I've brazed in cap tubes, txv's, reversing valves, all kinds of valves, never had one fail to my knowledge.

I've only been in the trade 9 years, so maybe not enough time has passed to tell yet.

Yep.

I've cleaned hundreds of plugged TEV screens on a store where I know the fitters did NOT use nitrogen.

Last store I started, the fitters used nitrogen "wherever they could" and I haven't had to touch a screen in that store.

:.02:

 

[cmclifton]

Not interested in what the book says...I want to hear about real life experience.

Has anyone ever ran into a system problem during service that you could 100% say was caused by brazing without flowing nitro/co2...whatever.

I've never once flowed nitrogen during service repairs, don't even pressure test. (my welds don't leak) :grin2:

Just braze it up, pull a vacuum, and get it going.

I've brazed in cap tubes, txv's, reversing valves, all kinds of valves, never had one fail to my knowledge.

I've only been in the trade 9 years, so maybe not enough time has passed to tell yet.

I've been in the trade close to 15 years, about 3 years ago I had a store with something like 25% of the cases struggling to make temp. They were all refrigerant starved. I went through and cleaned the screens, they were plugged with that flaky black soot that builds up inside your pipes when you don't purge your lines.

Also, please tell me you're joking.

 

[itsiceman]

Not interested in what the book says...I want to hear about real life experience.

Has anyone ever ran into a system problem during service that you could 100% say was caused by brazing without flowing nitro/co2...whatever.

I could not
I believe any restrictions I've ever had were caused by overheating, moisture or strait up piping issues causing oil return problems.

 

[Phase Loss]

JP

I'm not talking about starting a new store, where if they didn't flow on the install of thousands of braze joints...yeah, you get some plugged txv screens.

I'm talking in a service situation.

Stores been up and running for a while now. you get a leak on a cracked 90 down at a case.

pump it down, replace the 90.

I'll never flow in that situation. ever. never.

and everything has been ok...so far!

 

[Phase Loss]

I've been in the trade close to 15 years, about 3 years ago I had a store with something like 25% of the cases struggling to make temp. They were all refrigerant starved. I went through and cleaned the screens, they were plugged with that flaky black soot that builds up inside your pipes when you don't purge your lines.

Also, please tell me you're joking.

Yeah, I've seen that too...even on 40 year old stores.

that can't still possibly be soot from not flowing.

It's more likely burnt oil from high discharge temps.

And no, I'm not joking. I've never flowed nitro during a service situation. you're talking about a handful of braze joints at best.

IE: replacing a TXV, 3 joints, don't even wrap the valve with a rag...never had one fail....ever. Use a rose bud tip too, on full blast...for everything.

 

[KickedGinger]

Industrial grade Nitrogen has 7.3PPM of moisture
Carbon Dioxide has 11.3PPM of moisture
I really dont see how 4ppm could make a difference

 

[pherman]

Yeah, I've seen that too...even on 40 year old stores.

that can't still possibly be soot from not flowing.

It's more likely burnt oil from high discharge temps.

And no, I'm not joking. I've never flowed nitro during a service situation. you're talking about a handful of braze joints at best.

IE: replacing a TXV, 3 joints, don't even wrap the valve with a rag...never had one fail....ever. Use a rose bud tip too, on full blast...for everything.

Likewise. Never had a problem

 

[jpsmith1cm]

JP

I'm not talking about starting a new store, where if they didn't flow on the install of thousands of braze joints...yeah, you get some plugged txv screens.

I'm talking in a service situation.

Stores been up and running for a while now. you get a leak on a cracked 90 down at a case.

pump it down, replace the 90.

I'll never flow in that situation. ever. never.

and everything has been ok...so far!

I've done it both ways.

I can't tell a difference.


I also think that, given the size of the systems we're talking about, we've got multiple filters and driers to handle any extra oxides that are formed and, if we're doing our jobs properly, they are being checked and/or changed on a regular basis.

 

[Grayline]

that was the reason for my Thread.... Nitrogen or no Nitrogen?I know everybody wants to say they do it all the time everytime but C-mon guys....
Simple repairs and quick fix issues to get the Customer back up,I use it to purge as I weld in linesets or compressors but a cut out and weld back in a drier? to flow Nitrogen you always Have to Reclaim the gas ALWAYS... I say lets get real......