How to Flow Nitrogen While Brazing
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- čas přidán 7. 02. 2020
- Bert is back! He uses a setup he made for Jim Bergmann to demonstrate how to flow nitrogen while brazing. He also crashes the party at an install to film one of our installers flowing nitrogen while brazing in the field.
First, you will want to remove the Schrader cores from the suction and liquid line service ports. Nitrogen will flow into the system through one port, and it may flow out through the other service port or out of another opening in the copper. The nitrogen just needs to flow across the joint being brazed.
Then, you purge all the air from the lines by sending nitrogen through at a high velocity; purging flushes out the oxygen and will prevent oxidation from forming inside the copper tubing and creating restrictions later. We can control the velocity of nitrogen with the help of a regulator; some nitrogen regulators have specific preset settings for testing, purging, and brazing. Other regulators have SCFH gauges or a floating ball to indicate the nitrogen velocity. During the actual brazing phase, we can flow nitrogen at a very low speed to prevent air from getting into the lines.
When brazing, we also need to protect heat-sensitive components and surfaces with a wet towel or a heat-blocking putty (like Refrigeration Technologies WetRag). The copper should also be clean, and we need to be thinking about where the nitrogen will be entering and exiting the system.
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Big up from Costa Rica, i am a FIELDPIECE teacher , we are using a digital reports in classroom
Never knew that if air is available it may actually clog inside the txv. Thanks for the video
thanks Bert. the person that showed me didn't take out the schrader core when flowing. now it makes more sense!
I know this is an old comment, but here's my two cents. In this video example, it's a basic condenser and air handler install, so it was smart to remove the cores in this case. However, it may not be necessary to remove all the cores in the system. It really all depends on how you're flowing the system and where you want the nitrogen to go. Sometimes, instead of removing the cores, you can just hook up your gauges and let the nitrogen just flow out of the hose.
I work on commercial and industrial refrigeration. Refrigeration systems have all sorts of different controls and components where refrigerant flows through. Depending on your situation, you may not need to remove a schrader core. The most important thing is to understand how everything flows through the system. This understanding will allow you to control exactly where you want to flow nitrogen. If you work on systems enough, this understanding will become second nature.
@@paulcrandall2534 removing the cores important for the next step, vacuuming thw system and verifying decay leak rate.
Its amazing to me who been doing this technec for many years, that many veteran technicians dont do this. I remember in my younger years we use to use stay brite soft solder. This practice has been in text books for a longtime. Good work on the videos.
I know this is an old comment, but I'll say something anyway.
I agree with you. I'm a commercial/industrial refrigeration tech and I've seen many veteran service techs braze without nitrogen. They always say "the drier will catch it." I've been guilty of this practice too. If I'm out of nitrogen and I have a few more joints to do, I'll just braze it and not worry about it. It saves me a trip to the wholesaler and I have to get this cooler up and running ASAP or they risk losing thousands of dollars or more in product.
I've used soft solder a few times. It works, but I don't like it. Some of the old timers do it that way. I use oxy-acetylene with Stay Silv 15 brazing rods. That is my go-to setup. I like to see a solid brazed joint when I'm done.
Those are some nice regulators, save lots of money on nitrogen not to mention one won’t void any warranty on equipment if they install it properly. Nice share.
Nice video Bert!
That coil and line set you made up for Jim got pulled down to 500 microns in 30 seconds with his tru blu hose kit it was amazing!
Just what I was looking for. I needed a video that shows the process of flowing N while brazing.👌👌👌👏🏼👏🏼
Good video. But it was driving me crazy. Its called a schrader valve not a straighter valve. LOL. just busting your stones.
LOL I was going to say something too. Good video Bert!
I thought that was what he was saying too.
Yes, that was getting annoying.
That and oxydization. I know, I'm an asshole.
👍great video Bert.
Great job!
Great video!
잘 보고 갑니다^^
Thanks ^^
From Korea
When the trainee started brazing, I was expecting to see a turbo torch. The gross majority of new guys and residential guys I know use a turbo torch. It drives me nuts; but I'm a commercial/industrial refer guy. Same concept, just a completely different animal lol. I was pleasantly surprised to see your trainee using oxy-acetylene. Nice quick heat to get in and out instead of cooking the s#!t out of the joints with a turbo torch.
Just a little constructive criticism for the new guy(not so new anymore since the video is a couple years old)...I would've wrapped the service valves a little better and I would've added a drier. Especially since you're reusing the line set (unless the condenser already has one in it from the factory?). A sight glass probably wouldn't hurt either depending on how long and how high the line set goes. Otherwise this is a great informative video. It's very important to flow nitrogen.
Good video. So many installs and repairs are done with out nitrogen. I had a discussion with someone about the nitrogen usage and the heat flow while using it that I created a thermal imaging video showing the use and the heat flow direction in regards to the flow.
While you're brazing, the braze rod always follows the heat. You can drag a puddle just about anywhere using a torch. I'd like to see that on a thermal cam. Sounds cool!
It’s called a “shrader” with a “sh” sound.... not a “straighter” “str” sound 😂
Sorry, been in the field since ‘91, hearing “straighter valve” is like finger nails on a chalkboard 😂😂😂
The proper regulator to use for purging is a flow meter. You need very little flow, once the lines have been purged. Nitrogen has become expensive, and it’s good not to waste it. If the flow will extinguish a lit match, it is enough.
I know this is an old comment, but I'll reply anyway.
You make a good point. The nitrogen needs to be enough to extinguish the match. Not blowing the flame out, but actually suffocating the flame from the lack of oxygen.
Hvac Queen here: this video is great. I love my Victor Gear & regulators.
Love the vid but I wish you would’ve done it on a traditional/standard line set so I could understand how it passes through
Nice! I didn't see technicians using nitrogen while brazing. They say that the system has a new drier filter anyway.
Most of them service mechanics. I'm tired to speak about it and they declared tired to bring the nitrogen from the van. I do the brazing how I want and they're brazing how they want.
Great video but I have to admit that I have not ever done it been in the Business for 20 years looks like a good practice and the right way to do things
Thank you sir for service calls 😜
Oooooo I like that nitrogen valve!
Burt, those manifold hoses with the built in ball valve are sweet!!! What brand are they??
The question is what brand aren't they? Most brands make em.
10:50 - Can you get the canoe in the reversing valve positioned so the nitrogen flows through all the pipes at the same time, or is that a multi step process? I’m not sure how to proceed to be sure there is no moisture left at that point.
Great job Bert! Lol
That would be with the system pumped down? So you have to leave one side open meaning with the schrader removed?
Nearly 3 decades in the trade and I’ve never flowed nitro while brazing. Yea I said it.
Decent video. Just was looking for where the part saying the order of brazing. Everyone I've see so far just brazes in whatever order. Mostly they be doing everything outside first, then inside. I was told/taught to follow the flow of the nitro was the right way. Hard to find that on the internet.lol. By the way you said their was, "Oxygen in the air.".....😆 Kinda lost me some areas on here. Like when you pulling a vacuum, your also pulling the Schrader valves??? I thought, " You'd be just pulling another vacuum if they not in there.🤣 Or is everyone doing that wrong also??🤣
I know this is an older comment, I'll try to explain some of the concepts in the video.
Removing the cores will allow you to pull a nice deep vacuum relatively quickly. There's nothing in the way restricting the vacuum pump. But if you pull a vacuum with the cores removed, you MUST use a special vacuum rated core tool so you can put the cores back in when you're done. Otherwise the entire system will bleed out when you remove your hoses without any cores. When using the core tool, make sure you put the cores back in AFTER you charge the system and it's under pressure. Never put the core in while it's under a vacuum. You'll end up introducing air back into the system, even just a little bit, and you'll have to pull another vacuum again. I highly recommend Trutech tools. If you're confused about what you need, just give them a call and they'll help you get set up with what you need. They're extremely friendly and knowledgeable and, in my experience, they're much cheaper than what you get at your local wholesaler.
When it comes to brazing in a certain order, it doesn't really matter. The most important thing is to understand how the system flows and operates. This understanding should become second nature and it will allow you to approach it in a way where you'll know if nitrogen is flowing in the area you're brazing. There is no specific order. All the joints have to be brazed eventually. I also recommend using an oxy-acetylene torch instead of a turbo torch. Especially around service valves and TXVs. Those components have a lot of mass and can take a lot of heat before braze rods start flowing. Oxy-acetylene is nice quick heat that will allow you to get in and out instead of cooking the s#!t out of it with a turbo torch. I've seen a lot of guys screw up brand new out of the box valves using a turbo torch.
When you start heating up copper with your torch, the oxygen in the atmosphere causes copper surface to oxidize and black flakes will get into the system. Depending on how much oxidation gets in there, it will start plugging up the TXVs(or whatever metering device), filter driers, and whatever else is in the system. Since nitrogen is an inert gas, it will prevent the copper from flaking and will keep the inside of the copper lines nice and clean. In my experience, some oxidation in the system won't cause any problems, but the potential is always there.
If there is anything to take away from this video, make sure you understand the refrigeration cycle, think, and just be smart about your brazing practices. Once you work on enough of them, your understanding of the process will become second nature.
when i braze in a new compressor, scroll copeland, i need to have nitrogen, its it correct that i put nitro on low side and blow out on the high side? Becuse the compressor have a rewerse seal on high side in compressor and can damage the seal?. correct?
1:00 - how are you getting that to flow through a closed expansion valve?!
9:13 - What length of time would you give for the purge before backing the flow down to braze?
I made a mason jar to flow through and extinguish a candle flame within to determine the time for the size of the system that I needed to purge. Now I just time it based on that for that system. All systems are different sizes.
But a few minutes is basically it. I’m assuming like me you want to conserve nitrogen.
How do you know that pipes are full of nitrogen and you can start with brazing?
Good knowdge
Would using the vacuum pump work ? To remove oxygen while brazing ?
If pulling a vacuum while there are fittings yet to be brazed, what are you pulling into the system?
safety precautions: dont purge nitrogen in a enclosed space. I know because I learned it the hard way.
So install an external drier even if new outside unit has one?
One LL filter drier per system.
Most will say prefer placement closest to the metering device.
How do you know nitrogen has filled the whole system (time to start brazing)? Or just by guessing?
I built a flow through mason jar and put a candle in it.
When the candle goes out I give it thirty seconds more, then turn down to a whisper and start brazing.
Use the maximum pressure on the nameplate
Instead of nitrogen is there any reason you can't use CO2 as a purge gas for brazing?
What’s that regulator?
Save a txv, braze with nitro.
Does he keep saying "straighter" instead of Schrader ...
What can be done (if anything) if the contractor installer never purged with nitrogen while brazing a new install with new line set? I have witnessed this so often, i thought it was the norm!!
This is an old comment, but I'll respond anyway. What I would do is perform an inspection and preventative maintenance on the system. Change the air filter, wash the condenser, inspect and tighten all the electrical, and then check the pressures and temperatures on the system. Maintenance should be done every year. If the pressures and temperatures look good, I wouldn't worry about it. If there is an issue, the system will have to be opened up to clear the restriction and a filter drier should be installed to capture any residue flowing through the system.
It's usually a pretty straight forward procedure. If you're a technician, you should know how to do all this(or you're learning how to if you're new). If you're a home owner, I highly recommend getting in touch with a reputable service company and get on a service plan. They'll come out and service your equipment once a year and you'll usually get a discount service calls and repairs if you end up with a problem.
Check temperature drop across filter drier.
If filter clogged with trapped debris it will form a restriction and result in a measurable temperature difference between the inlet and outlet of the filter drier.
😂 awesome
Schrader valve. If that purge regulator only went to 150 psi it would be perfect for what I do.
What do you do?
You can set that regulator to a constant 150 psi all day as long as there is at least 150 psi left in the nitrogen tank.
omg is he saying STRAIGHTER valve
Damn i got this wrong in an important exam question 😢
What’s the price on the regulator?...
its a VN 650 its around 150-160 USD
The little flow meter is 30$ it works well
on sale at Johnstone's for like $120 i bought one last week
How many Cubic feet to purge the average system. The flow meter tells a rate of volume, but how much volume should be sent through. Do stick your finger on one end, count the seconds it take to build 15 psi and then multiply that. How many time over should the nitrogen displace the evaporator and tubes ? If you flow 20 CF/hr for 15 second then cut down to just under 3 CF/hr does that do it, if you diddle for a minute and then spark up the torch. I'm pretty sure on a big unit, one would want to calculate the cubic feet needed, rather than merely guess. Maybe you light a punk(smoldering stick) and wait till it gets snuffed out.
How bout you turn on the purge, light a cigarette, take about 4 leisurely puffs then call it good. Your purging kid, not splitting atoms.🤯
@@mitchdenner9743 Nitrogen and oxygen are nearly the same density, so it is merely the volume of the tubing -- a "fraction" of a cubic foot.
@@dunckeroo1987 I give up
@@mitchdenner9743 But thanks anyways> I got obsessed with the math and 4 puffs would be fine.
@@dunckeroo1987 😐🤔😁
Nice vid Bert 👍🏻💦
What is a strayder? lol
Schrader... Shrayder... SsshhhhrrrraaaDDDeeerrrr... NOT straighter 😂
How many people does it take to put an ac in hahaha all apprentices
"Straighters"
Not wearing shaded goggles can mess up your face eyes!
Depends on the light where you are working. Sunny outside, not much effect on the eyes. Dark inside? You will not be able to find your way out for 5 minutes or so.
Should of went to texting school. I hope you all know what I mean.
Idk, I flow nitrogen everytime I service a system and it doesn't seem like a big fucking deal to me....Also, it makes blowing out drains or excessive flush in the evaporator when doing a pull and clean much easier than anything else I've been able to think of so.... "WTF do you do without flowing your nitrogen?" would be a good CZcams video title. And, I don't have balls at all on my nitrogen... So wtf is a ball? Huh sack?
You-tube is just complete and utter contemptible trash these days. You start to watch a video. It plays for five seconds then the video freezes....the audio continues. BUT!! You-tube is able to play umpty-zillion ads between each ten seconds of the video you want to see without a pause in audio or video!!!!!!!!