Our Inverter Mini Split Resources: Mini Split Book on Our Website- www.acservicetech.com/mini-split-book Mini Split Paperback on Amazon- amzn.to/3ytHJSs Mini Split Paperback on TruTech Tools- www.trutechtools.com/BooksGuides?aff=8 Mini Split E-Book on Google- play.google.com/store/books/details?id=HN-iEAAAQBAJ Mini Split E-Book on Apple- books.apple.com/us/book/id6445178399 Our Single Speed and Two Speed Air Conditioning Resources: My Paperback and E-Book: www.acservicetech.com/the-book My Paperback: www.amazon.com/shop/acservicetech Read the book reviews on Amazon! Check out our new Articles at www.acservicetech.com/articles Support the Channel by purchasing tools through Tru Tech Tools! Use this link www.trutechtools.com/?Aff=8 Save 8% at checkout using code "acservicetech" Tool List- www.amazon.com/shop/acservicetech Support- www.patreon.com/acservicetech For those that are looking for the tools used in the videos: (Linked Below) Here is a link to the Nitrogen Flow Meter amzn.to/2brvoBg Here is a link the Nitrogen Regulator amzn.to/2bXdR5f Here is a link to the air acetylene torch setup amzn.to/2aQalsb Here is a link to Refrigerant hoses with valves used in the videos- amzn.to/2aBumVI Here is the Link for the Yellow Jacket Refrigerant Manifold Gauge Set used in the videos- amzn.to/2aenwTq Here is a link to the UEI DL389 Multimeter used in the videos- amzn.to/2av8s3q Here is a link to the Hilmor 4 port Aluminum Manifold Gauge Set- amzn.to/2m4QLik Other tool links can be found in the video description section. ACSERVICETECH is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.
I would still only run 3 cfh at the inlet through. If there is a lot of friction until the nitrogen can get out through the other side then it will take the path of least resistance and that may force a little pin hole through your molten braze for the nitrogen to escape. You don't really need the psi but just for the oxygen to not be present in order to prevent oxidation. Hope you enjoyed the video! Thanks for your comments and thumbs up!
You would need to braze in access valves since you have to have the line be open while brazing and to weigh refrigerant in when you are done. this is what you would install after piercing and recovering refrigerant -- amzn.to/2i2JwE8 --or this size-- amzn.to/2iQ1tIn
You only need enough flow to snuff out a lit match at the outlet.Not blow it out. If the match extinguishes, it means there is no oxygen. Flood it first with more flow and then turn it down just enough to keep it moving..
I enjoy all these educational videos you show us. I have learned so much as a newbie to the field. Although it cracks me up every time u say "alright" Ha!
Yeah those were in the earlier videos. I don't believe I am doing that now. That was my old verbal que for eye contact in the classroom. It was a hard habit to break when transitioning to video, thanks
Such an honor to have met you at the HVACR Training Symposium at Kalos Mr Mig! Going to pick up your recommended #Uniweld tools on my next paycheck. My boss is old school and set in his ways. So, he never uses nitrogen when brazing. But we have a very hard time getting our vacs down to 500μm. Wasting a lot of time! And creating future problems. So as Ive been taking Trevor Matthew's Compressor Masterclass, the "Field Practices in 7 Steps" section in week 1, this was discussed in detail. So I looked for your video here to find the best practices for doing so. Thanks as always for all your mentorship to the HVAC+R techs!
Robert, you are such an encouragement to hear from! if you ever have questions just message me directly on linked-in or email me at info@acservicetech.com
Thanks for this video and all of your videos; they're really helpful. Could you have brazed the joint on the suction side while feeding the nitrogen from that side? or would you have needed to feed it from the other side to braze that joint? Anthony
So there is no issue with nitrogen flowing through TXV or piston with 3psi pressure? Also How do you confirm it is coming out from the other end since pressure is so little.
Hi, its always awesome to follow every part of your post we are gaining knowledge. Only I have doubt like, if still the same outlet (SERVICE VALVE) to purge, when we solder during compressor replacement? vise versa
Unfortunately you can't flow nitrogen through because the compressor will not let it through so we do what we can when we can for the best possible job, great question, thanks jhon!
Could I purge the lines first, then set to braze flow to remove some of that potential leftover refrigerant from the line so that I don't get phosgene gas Creation in the process of my brazing?
Thank you for your videos and book. They help me a lot, thank you. I have a R410 Ptac that has hole on the suction line near accumulator. Can I just seal it? How do I braze with nitrogen if there are no service valves on the system?
Since you said that the refrigerant was “in the unit”, did you trap it in the unit by using the compressor while manipulating the service valves? And did you then do a recovery from the liquid and gas lines? (Testing myself from what I think I have been learning. Thanks. )
That is absolutely correct, a pump down, and recovery. It is possible to do a full pump down so that the unit stays below 0psig though without a recovery, awesome, thanks!
Gonna try out the VN-500. Been watching and noticed they purge the lines before adjusting to the braze setting. How long should I purge the lines with Nitrogen prior to adjusting to the brazing setting?
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!!
great video, question say i pump down the system to fix a leak on the suction line. and their is oil residue on the inside of the pipe when you go bacl to braze. obviously you dont want that oil burning off inside the line while brazing. whats the best way to clear it out if repairing an old line. thanks
You just try to blow it out with nitrogen or wipe the area. Flow nitrogen through at 3 cfh. Be very very careful and avoid breathing any phosgene gas that will occur. Thanks
This is standard procedure in Belgium. Weld with nitrogen> leak testing with nitrogen > vacume until at least under 270 Pascal> start up unit. Or you're not allowed to build one in the first place.
Yeah cubic feet per hour cfh, I put a not in that video but since it was an annotation, you would only see it if you were on a computer and not a phone, thanks and good catch!
I’m new at this but if nitrogen is flowing towards the evaporator and then to the txv, I did not know you can flow nitrogen to the txv and continue flowing ?
I’ve watched a few videos of people brazing linesets, and one thing I’ve noticed is that not one of them use flux before soldering. Is this because of the chance to contaminate the inside?
This is brazing with 15% silver brazing rod. The phosphorus in the rod fluxes it. You would flux when using lower temp solder such as Stay Brite 8. You would use stay Clean product. Look up acservicetech brazing playlist for more videos and brazing and swaging tools along with rods are found at amazon.com/shop/acservicetech thanks
AC Service Tech LLC ... Thanks for the reply. That makes sense. Is there any specific reason silver solder is used, rather than say, a lower temp solder used on water lines? Seems like there’d be less of a chance to have the joint blackened with a lower temp solder., but I’m guessing the lower temp solder can’t withstand the high pressures.
It is higher strength, the silver in it allows not to crack as easy. Low temp solder introduces a small amount of acid into the system at each joint so that is why a lot of us braze. Many techs solder with stay brite 8 and report no issues, thanks
If u don't use nitrogen, won't the in-line filter pickup the oxidation residues left inside the lines? So is nitrogen really to prevent oxidation debris or to provide for a better weld process?
Yes the inline filter drier will pick up a lot of it, will increase friction on the oil and refrigerant movement across it, mix with possible oil additives to clog up txv's moving parts, or could clog the strainer. very small particulates can get through the filter drier and comprimise the compressor. All of this because some techs are not running nitrogen through due to what they say is time. Once one knows the procedure though it really does not add much time at all and won't make leaks when brazing. It just takes a bit of getting used to then one is fine. Thanks and here is part 1 of a 3 part video using it - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-SEe9HXmzvAY.html
Where would you put the nitrogen hose on the unit for the suction line brazing. Would It Go on the liquid line? Or would it stay on the suction line. I went to school for this. However my teacher can't show me everything. There's so much to know.
You would switch it to the other side so if you were brazing the suction valve, the nitrogen would be on the liquid valve, when brazing the liquid valve, the nitrogen would go on the suction valve, thanks!
So how do you braze the condenser unit before the lineset is soldered at the air handler? How will the nitrogen flow through the coil to get to the LL connection you are brazing or vice versa? Also how will you solder the air handler? Say if you are brazing the LL @ the AH, would you just connect your nitrogen to the LL at the condenser unit?
I usually wait until I have everything connected to braze the outdoor unit in. This way the nitrogen flows through the whole thing. I have 3 videos, part 1, part 2, part 3, where I show how I brazed a whole system in. Look up "acservicetech brazing" thanks
10 psi would be plenty, 5 psi would be better. Your only using a small tip. Remember 15 psi max for acetylene. Above 15 psi free acetylene can dissociate violently (ie BOOM). One of the first things we learned in welding school.
Where did you get your gauges set up? Or what make are they? No wonder I have such a hard time doing it with nitrogen, as I don't have that second flow meter attached
Yes, you can tin tape a refrigerant hose to the end of the pipe and make sure you are brazing a good distance away from the tin tape. Then tin tap the other side and poke a small 1/4" hole in it as a purge vent.
Could you mention what position the hi/lo side service port king valves should be in while flowing nitrogen, e.g., front seated, back seated or 1/2 way? Great Video!
Great Question! So in this video these are not king valves. Check this video out to see king valves----ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eXkqOS_qywo-.html-------In the video you commented on-On new units with refrigerant inside the condenser the valves would be front seated as you are brazing the lineset and evap in. On a system where you are replacing the compressor and have previously recovered the refrigerant you would have them backseated. On king valves brazing lineset on system with refrigerant in the condenser you would have the king valves front seated. If you were replacing a compressor on a system you previously recovered you would have the valves mid seated. back seating a king valve is for disconnecting from a live system because a king valve does not have a Schrader to hold the refrigerant in. Thanks for your questions!
Once I am ready to tie into the furnace how would I do this set up? The condenser is not even set yet set yet the the lines would still be open at that point. Would you cap them off at that point? All this stuff is still new to me and I really want to make sure I am doing it the right way.
I have a small crack in the liquid line at the bend just above the compressor. tight spot, wondering if I should use 15% or higher and also a jewelers torch so I can avoid over heating / damaging the compressor? Did this happen because the 3 compressor anchor bolts were tightened down too much causing too much vibration on the liquid line.
15% silver braze rod will work but you will need more heat than that because the metal of the compressor may act like a heat sink. As long as the system is empty of refrigerant, the tube should be heated up quickly and brazed. Also be cautious of any phosgene gas that can be created during brazing since there is refrigerant oil in the line, thanks!
so do you put the nitrogen in the high side and let it flow out the lowside? Does it matter which side you flow the nitrogen into the system? thanks, let me know. ;)
Can i asck you about this regulator at tme 02:20 First you open the key knop of the Cylinder then you open the key of the Regulator then you open the flow metter The is the flow meter help us to the consumption of the Gas and the Regulator help us as safe Guard for the Flow meter because what i know is every pressure level = to Level of Flow in medical use for example we use the Maximum level of flow meter in order to achive certune amount of pressure either in CM H2O or in MBar
Is there a limit to how far the Nitrogen at such a low CFH will actually travel and where it becomes ineffective? I do large scale VRF jobs with some line sets that exceed 100+ feet and multiple Y's (refnet's). For example, I may braze a 1/4" service pigtail on the starting point of a Suction line for running my nitrogen through. It may branch off to 10+ air handlers that are maybe 100+ feet away before it sees it's first split. Am I okay to just continue running 3-5 cfh at the same service point when im down the line 100+ feet? Just seems like the nitro flow becomes redundant when you reach a certain distance UNLESS you up the pressure to compensate for the distance? Any input on this would help. Thanks!
If it is a long run or many units connected together, first purge at 20 cfh and then you can drop down to 5 cfh instead of 3. Once the air is removed from the initial minutes of purging, this flow rated should keep it good, thanks!
If you are brazing a copper line inside the OD unit within 15 inches of the compressor how do you pump in nitro while brazing that section . Do you disconnect the line at the compressor so the nitro is flowing out while brazing and not entering the compressor ?
Sir, as this is a demonstration you should have shown how clean is the inside portion of the brazing section- after the brazing is done - when nitrogen is flowing as opposed to ordinary brazing.
So if u have four joint to braze the inlet of evaporator....the outlet of evaporator...the suction and the discharge( liquid line)side of condenser...which one do start first from start 5o finish...and does it matter if u have a txv?
Disconnect the bulb on the txv and dont cut out the section for the filter drier or install the liquid line filter drier until the very last thing. It doesn't matter where you start but that you have a clear channel from where the nitrogen enters until where it escapes. The fittings can just be pushed over the tubing and yes a decent amount of nitrogen will be lost there but that is ok as it will continue to make it through the tubing. The nitrogen will have displaced the oxygen. I would advise that you not braze right where you are running nitrogen through so you don't melt your hose. We are talking about doing the best job with what makes sense, that's all. I believe these three videos in a row part 1, 2 and 3 show me brazing through the whole process. Thanks for your question. Let me know if you have more questions after those three. Thanks
I was flowing dry inert nitrogen through to avoid oxidation inside the tubes. Then a pressure test must be done, then a vacuum down to 500 microns, then weigh refrigerant in, thanks
how does the nitrogen run through to the outlet of the high side service valve if the coil has not been brazed yet? wouldn't the nitrogen leak through the unbrazed joints before reaching the high side valve?
Great Question! The object is to just get the oxygen out which it will do. Yes much will leak out but still there is enough to push the oxygen out at the other service valve, Check part 1, 2, and 3 for the whole brazing process with nitrogen. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-SEe9HXmzvAY.html
How would you do this setup brazing in line sets that are 9 ft up and not hooked up to the unit yet. I am working with 20 ft sticks of hard copper that can be up to 100 ft long line sets and we are brazing it all in without nitrogen. I know nitrogen is an important process when brazing because of the damage it can cause but I am working under someone and I kind of have to do what I am told. I want to do it the right way so if you wouldn't mind explaining how I would hook it up. Like I said none of the copper is hooked to the condenser or furnace so I would just need to run the nitrogen through the suction and liquid line to make sure I am not oxidizing the inside.
You can drill a hole in a cap and braze a service valve in it. Put the cap on the end of the pipe and tin tape it on. You would be brazing 20 ft or more away so this won't fall off. Keep the nitrogen tank on the ground and use 1/4" hose couplers or a gauge set to connect two 5' refrigerant hoses together to extend reach to 10' high. --- amzn.to/2i2JwE8 -- I do agree that you need to follow what your told until you are in the position to make the positive changes you want. Also when just running linesets before installation of the condensor or evap many times we braze these access fittings on and do a pressure test during other building processes to make sure our linesets were not damaged. You would just cap the other side or connect the other side with the two pipes together. Thanks, hope this answered your questions!
acservicetech acservicetech acservicetech acservicetech okay so for instance say I am going to braze 40 foot of line set I would braze into a cap a service valve on both liquid and suction line. Now at the other end of the liquid and suction line is that left open so the nitrogen can escape? I think you mentioned tying them in together but how would you do that if the liquid line is 3/8 in and suction is 7/8 would you need some kind of reducer so they could tie in. Guess I am not understanding how you could tie the two in together since they are free standing and not hooked to anything yet.
If you were to tie them together on one side after you are done brazing to run a pressure test through both then we usually just crimp the suction line over the liquid line and braze the seam. It will hold pressure. I do this with channel locks and linesman pliers. In reference to brazing just the vapor line put the cap on one side and leave the other side open for the nitrogen to escape. Here is the link for the smaller tubing service valve -- amzn.to/2iQ1tIn
The same method. Search out "acservicetech Brazing with Nitrogen playlist" There is a 1st, 2nd, and 3rd video there that will show the whole thing, thanks
Yes, you just switch the location of the yellow service hose attaching to the service valve. Check out the brazing playlist 3 part video.- ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-5V_da4ymlvM.html
Black oxidation occurs when brazing without nitrogen and this would get stuck in the system and recirculate. It could clog up the filter drier, reduce lubrication on the compressor or could react with rust inhibitors to make the txv stick, thanks
Yes you need to make sure that you have available fresh air. To do so possibly use a fan or wear SCBA. I was only briefly putting the flame to the copper in this one, thanks!
You didnt address this but after brazing the suction line would you move the nitrogen over to the liquid side when ready to braze that one? Or just leave it on the suction?
We leave it on the liquid line while brazing the suction line and leave it in the suction line while brazing on the liquid line because you will have the tubing inside the house connected. You can braze the inside with the nitrogen on either port. Have you checked out "acservicetech Brazing with Nitrogen Playlist" I have videos on brazing in a complete system and what happens when you don't braze with nitrogen, thanks
This looks time-consuming, especially in a supermarket setting. isn't it better to braze it all and change all filters at least 3 times at startup? Anyone has opinions about this. When I'm welding 30 systems 90-150ft each system. I rather change the rack system filters 3 times at startup. I clean all cases valves and walking valves as well, and I end up with zero particles? any ideas anyone has done what I do?
Im no expert but I saw a another video where the tech flows the nitro through the liquid line traveling through the txv and coming backbout the suction line. He chases the nitro as he brazes. For example he starts with the liqiud at the compressor. Then goes up to the evap continues with the liquid the the suction at the evap and then comes back down and finishes at the suction at the compressor. Chasing the nitro.
Hey Christian, the only issue with that is you don't want to have your nitrogen hose on the port of the first service valve you braze because you will be melting the rubber gasket on the hose. If it doesn't melt, it will still get deformed some, thanks and great observation!
It will tank awhile for the dry nitrogen to push out air or residual refrigerant thru the entire system, NO way to really tell how long to purge out as every system a bit differant, keep in mind long line sets and the A-coil / evaporator ALL has to be purged!!!!
I believe this is the same reason manufacturers have chosen to stick with flares instead of braze joints on mini splits. They believe the majority of techs are not doing it and I think that is our present state, thanks Mike!
I did not see that ball floating at all. Make sure you have at least 5 CFH flowing through the flow meter as the diaphragm is not sensitive enough to hold the seat open. Also you need to FULLY wrap your service valves! Or better yet, transition to StayBrite #8.
Hey Walter, that was an older video but yes the ball is floating. It is not like the turbo torch version. The ball only floats about 3/16 from the bottom when at 3cfh. I usually flow more through before brazing and then tone it down to 3cfh while actually brazing. I always wrap the service valves. I also disconnect the bulb on the suction line of evaps that are equipped with the txv whenever possible, thanks Walter's Playground, all good topics!
Here is the link to the 15% braze rod I typically use. I use 15% on all systems and that would be considered the best thing to do. Also I have not found a time even on very small systems when I could not use a braze rod vs silver solder. Braze rod is also required for r410a systems. No flux is used. - amzn.to/2q0KHN5 ACSERVICETECH is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.
Nitrogen is not really an inert gas like helium, argon, etc. etc. . Nitrogen will combine with other elements to make compounds. Just wanted to correct you on that.
Very good. However I hate to say it most of the people that do the braising don't use the nitrogen. I've gotten onto them so many times and they threatened to even fire me because I made such a big deal about it. There is a lot of corruption in this industry to.
If you are in a lower position in the company then you kind of have to go with the flow but when you are running the job site yourself then you can make sure that those under you are doing it properly. It is a waiting game sometimes for newer techs, thanks!
