Hvac brazing 

Im glad you liked it. Dont worry about how many times you get it wrong, keep working to make it better.

The torch tip must be moving at all times...holding it in one spot will damage your tubing.

Just takes practice

As long as nitrogen is flowing, it does not matter

I oxy propane is possible. Propane generates less than 10% thermal energy. 10 oxygen and 5 acetylene is a good start. Some people like different numbers and it depends on how big the pipe is.

I will try to get to it. Still setting up the lab at the new school. Non condensibles will have the same symptoms as a restriction. With proper airflow you will see a High superheat and high subcooling. I have a paper somewhere in a box I made for that. I will try to find it this weekend. I recomend using the same solve for both. Recover all the refregerant. Open the metering device and check the screen and look for contamination. Purge some nitrogen threw the line to see if there is any restrictions. Cut out the old drier. Braze in the new dryer while flowing nitrogen. Pressure test with trace amount of refrigerant and a sniffer refrigerant leck detector. Pull a vacuum to 259 microns not to rise above 500 after 20 min or manufacture recomendations. Recharge with new refrigerant.

@@love2hvac Thank you. We are rooting for you here in New York to succeed at your new home 😊. Btw you inspire me to teach my coworkers and I make them all watch your videos. Thanks for everything

Yes. Just remember when you pump down you don't always know the condition of the refregerants or how swell the previous tech dehydrated.

For copper to copper I recomend 15%. It will be a stronger braze that will hold up to vibrations and much less likely to be a call back later on.

I prefer external equalizer, it gets a more accurate superheat reading since it is getting it pressure at the end of the evaporator. Internal gets the pressure right after the txv, and does not account for pressure drop of the tubing in the evaporator.

@@love2hvac Thank you!

For brazing I remove the cores every time. It does not take but a few seconds. They are very small and sensitive to heat. It is also very difficult to flow nitrogen with them in place. That said, Never argue with your lead. Eventually you will be in your own truck.

@@love2hvac That last part is true..hehe. But you're right. Thank you.

I do prefer oxy acetylene , air accetlyne second

I should have had another rag inside behind the panel. It is a good idea to move the wet rag over the joint as soon as its complete to allow for annealing. Annealing for copper is keeps it soft where as annealing for steel makes it harder and more brittle.

@@love2hvac ;-). thanks for the series!

@@love2hvac I think you mean quench. Quenching copper anneals it making it soft. Quenching steel will make it brittle. Annealing is a term used for process of softening metals. Thanks for the video. Nice.

Depends on the application. Most of the time for Cooper to copper I use 15%silfoss

thank you so much

Great question Bob, If it is a threaded Threaded TXV, I just leave the TXV out until all the brazing is done. Leaving it attached as if it was a fixed till I complete the brazing. If it is a pre-brazed TXV inside the coil, then I will add a service port outside the evaporator on the liquid and the suction line and push nitrogen threw both lines outside with a tee.

@@love2hvac Thanks for the quick reply!!! Nitrogen will then flow from the injection point outside to the newly added service port. But it seems to me that it won't get to where it's needed - the actual braze point for the TXV which is downstream from the newly added service port. Am I overthinking it? By the way, yours are by far the best HVAC training videos I've seen so far. I've forwarded them to a couple of my apprentices.

@@cleansebob1 yes your right. It is not nearly as good as it flowing past the braze. The main purpose is to keep the oxygen out to prevent oxidation. So while it is not as good it still limits oxygen. Thanks for the complement, I'm still learning every day. I Iove this trade.

I hope not !

Safety note, don't get into the trades, it's too dangerous.