in this video we're going to show brazing using an oxy acetylene torch rigwe're going to start with brazing and an air handler and condenser though these practices apply to all sorts of Copper to Copper bracing
first when brazing remove any Schrader cores to ensure that you don't build up any pressure in the system which can blow out your brays
you can also use the insert of a core remover tool to remove cores in this case we're showing a new condenser that doesn't have refrigerant in it already if you're working on a system that had refrigerant in it prior
make sure to follow proper recovery
practices and get the system to atmospheric pressure before proceeding before cutting copper in the first place
be sure to clean it with an emery cloth or other abrasive pad
Reem or deburr the copper tubing here we're showing how to do that using a navac deburring tool you can see that
when you cut copper it pushes a burr into the inside of the tubing this Burr , can create turbulence if left in place .
use the deburring tool to remove the Burr and ensure that the Burr or particles do not fall into the tubing
some tax in critical situations will opt to use needle nose pliers inserting them into the tube and twist back and forth
rather than risk dropping shavings into the tubing with a deburring tool , use your judgment and your own company
policies where these situations might apply here we show the effects of failing to ream or deburr it creates turbulence and turbulent flow on the outlet side resulting in an unnecessary friction and resistance to refrigerant flow
keep in mind that deburring is especially important when making connections like flare connections where the bur can impact the quality of the flared surface here we show tipping the copper downward and tapping it with the back of the deburring tool to ensure
that no shavings fall into the tube also make sure not to over deburr in cases where you're going to make a flare connection this can thin out the edge and cause cracking when fitting your tubing together make sure the gaps are not too large this can result in poor capillary action creating a braised
joint that's really just a cap over the edge that can be Fragile the goal is to draw the alloy into the joint if you have gaps that are too large be sure to use reducers or bushings
next we purge the air from the system then we move it to brazing mode or what we call flowing nitrogen while brazing which flows a very slow amount of pressure three to five scfh or standard cubic feet per hour some nitrogen
Regulators like the Western Enterprises regulator on this tank have preset flow modes with a gauge to show you how many scfh you're releasing from the tank if you don't have a flow regulator you can instead set a regular nitrogen regulator
t-handle to a point where it's just barely Whispering a flow of nitrogen three to five scfh is a tiny almost imperceptible amount of flow
before brazing make sure you have proper safety equipment safety glasses gloves and a fire extinguisher it's also a good idea to have some wet rags and a bucket of water handy
to protect the critical system components while brazing we're showing using wet rag heat blocking Putty from Refrigeration Technologies
we use this to protect things like service valves the paint on the compressor expansion valves and sensing bulbs
next we're going to show the proper setup of an oxygen and acetylene torch rig
first keep in mind that you're not supposed to use oil on the threaded connections of your Regulators this is especially true on the oxygen side as oil or lubricant on the oxygen threads
can result in combustion unless it's specifically designed for that purpose first connect your oxygen regulator to the oxygen tank clockwise or righty tighty the same is true for the regulator on your acetylene tank , use a backing wrench and make sure they're snug no need to over tighten
next connect your hoses to The Regulators in this case the oxygen is clockwise to tighten
whereas the acetylene is counterclockwise to tighten the hoses to both the regulator and the torch handle assembly , use a wrench to tighten them to Snug
next and very importantly choose the proper torch tip for the job at hand use manufacturer's charts to decide on an appropriate tip size depending on the work being done larger tips produce more , BTUs and are the right choice for larger jobs but this will also affect the pressures you should set your oxygen and acetylene to though many technicians myself included will typically use a standard setting like seven for acetylene and 11 for oxygen most charts
will show a balanced approach like 7 and 7 or 5 and 5. again the only real way to know is to consult the tip manufacturer on the appropriate regulator settings
also consider using specialty tips like a rosebud tip which is very good for larger jobs spreading the heat out or a hook tip for tight areas
next turn your regulator adjustments counterclockwise closing them off completely
then open your tanks use a refrigeration wrench for your acetylene tank do not use a crescent wrench or channel locks
now open your oxygen tank at this point bubble test all of your connections this is an important safety step
Now set the pressure for your oxygen and acetylene regulators , when setting the pressure the torch
- handles have to be open for dynamic pressure and bubble test the hoses
as I mentioned before there's no one tip in setting select the tip based on the job then set the oxygen and acetylene at the regulator not at the handle at the handle the knob should be almost fully open you can make very fine adjustments at the handle but in general it shouldn't be how you set your flame turn lockwise for higher Outlet pressure on your regulator and counterclockwise for lower Outlet pressure on your regulator
next use a proper Striker to light the torch the best practices are to start with acetylene only but you may want to be careful because lighting and acetylene only flame can create carbon
that can cause smoke detectors to go off or create black stains inside spaces
once you get comfortable with your torches you may be able to light them with oxygen and acetylene already mixed . this is a common field practice
next mix in the oxygen a carburizing flame has a primary and secondary feather a neutral flame which is what we're typically looking for or slightly carburizing has a very small secondary feather
an oxidizing flame has no secondary feather at all and we want to avoid that one try to get as close to a neutral flame as possible
when heating up tubing start with the male segment allowing the heat to conduct down into the joint keep the torch moving moving it in and out to get the entire joint to dark or medium cherry red or at least one whole section of the joint to dark or medium cherry red
this will allow the alloy to draw into the connection and create a nice cap on the edge do not just cap The Edge it's critical that you get the entire joint to that cherry color and draw the alloy into the joint that's what actually makes the bond next we're going to show why it's so critical to flow nitrogen at that three to five scfh
if you fail to flow nitrogen cupric or copper oxide can build up inside the tube which can cause systemcontamination clogged screens dryers and expansion valves
to shut the Torches off shutting off , oxygen first and then acetylene is generally considered to be the proper shutdown process that prevents it from popping back into the tip but again generally you shut them off simultaneously as quickly as possible as field practice always store tanks with Regulators turn counterclockwise and the valves off
next we're going to show some common base metals that you need to know how to work with
copper is by far the most common but keep in mind that something that looks like copper could be brass or copper plated steel when you burn through the copper plating on copper plated steel you're working with steel and you have to treat it as Steel
copper conducts heat very well meaning that heat moves through it easily it's also flexible and easy to work you can anneal it meaning you can heat hard copper to make it soft at over 1000 , degrees its temperature can also be easily estimated by color based on the chart shown here with dark to medium cherry red being the target color for most Alloys that's also true of brass and steel with all of these Metals make sure not to overheat and burn a hole into the tubing copper is also handy because it can befluxed with regular phosphorus bearing
Alloys we often call these thaws copper Alloys here are some common Alloys that would be used within the Harris line other brands include Lucas and solder weld separate flux is not required for Copper to Copper brazing and using flux will just result in a higher likelihood of system contamination
the phosphorus does the job brass is a softer metal and it's copper plus zinc usually used in cast Parts like valves it's less thermally conductive than copper and has a lower melting temperature
when working with brass it's best to work with non-phosphorus rods like a 45 or 56 flux coated and work with a separate flux you would gently be using a paste flux in some cases you can get away with using phosphorus bearing rods
with brass but the best practice is to use a high silver content with flux coated or separate paste flux here are some of my favorite products next we have Steel
you'll run into some valves that are made of steel and you'll certainly run into Steel on compressor stubs if the copper plating has burned through and in some cases the stubs may just be Steel , when you're working with steel do not use phosphorus bearing rods any Rod that says Foss on the packaging or as phosphorus in them should not be used on steel use a high silver flux coated Rod or a high Silver Rod or wire with a separate paste flux as shown here and finally we have aluminum it's rare that text will work on aluminum in the field but it's becoming more common it has a much lower melting temperature and gives you no visual color indication of Target temperature generally speaking you rely on the flocks to tell you when the temperature
is Right special Alloys and flux are required you will not use the same Alloys and flux that you used for Copper Brass or Steel when repairing aluminum and we're showing an evaporator coil here we also recommend using an aracetylene torch or a map gas torch generally when working with aluminum here we're going to demonstrate using alloysol by solder weld which is a product I've used a lot we're using it in conjunction with a Turbo Torch air acetylene swirl tip I like to use a number three or a number five when doing this sort of repair this is a repair
I've done a lot of this repair can be done inside the coil pack or on the u-bends as shown here first heat the tip of the rod and place it in the flux
next Heat the base material then melt the flocks over the base material keep the heat on the flux until it goes clear and quiet then hold the rod over the area holding the heat over it until the alloy goes flat and quiet then quickly back away , finally clean the flux off and you have a permanent repair again this product is specifically a repair rod
now we're going to show a more common type of product which is an aluminum repair Rod or wire with a separate low temperature flux this is an indirect heating method meaning that you apply the Heat and then you apply the solder once the heat has been removed
first heat the base material apply some flux around the area heat until the flux begins to Bubble and then go quiet then back the heat off and apply the rod over the area there are several products that work in this way and this is just a general procedure to give you some ideas always follow the specific manufacturer instructions there are other aluminum repair rods that have a flux directly inside the rod which can also be used effectively when complete clean off the area pressure test and bubble test to confirm that you've completed a leak-free repair aluminum can be successfully repaired in many applications we've done so in everything from tubing coil pack and even micro Channel when using proper products and techniques
now back to the Copper brazing here we show completing all of our connections removing the wet rag Putty for reuse in the future and cleaning all the connections as a note allow the connections to cool off for several seconds before cooling them with a wet rag inspect all of your connections with a mirror both before and after pressurization and bubble testing
now we're going to put core remover tools on the system and prepare for our pressure test and later our vacuum pressurize the system to the allowable maximum test pressure of the evaporator or condenser whichever one is lower bubble test all of your connections and check with a mirror , spray the soap bubbles on flat and quiet and ensure that there are no bubbles whatsoever including microfoam
you have to let the bubble sit for a little bit before you check for those microphone bubbles allow the pressure test to sit over time and ensure the pressure doesn't drop at all
this video is showing you how to braise Copper to Copper work with some other base metals and some basics of how to repair aluminum thanks for watching our video if you enjoyed it and got something out of it if you wouldn't mind hitting the thumbs up button to like the video subscribe to the channel and click the notifications Bell to be notified when new videos come out HVAC school is far more than a YouTube channel you can find out more by going to hvacreschool.com which is our website and hub for all of our content including
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thank you foreign this is a leeon from https://www.youtube.com/@HVACS
KEYWORD Oxygen Mapp Torch Kit Welding Kit