Correctly brazing the copper tubing is an important part of installing HVAC systems. Students braze pieces of copper and connectors together and pressurize to test for leaks.

Students use a flaring block to create flared connections.	The instructor explains the proper procedures for lighting an oxy-acetelene welding torch.
By setting the regulators at the proper pressures, the flame can be adjusted to the correct size and temperature.	Students braze their copper components with filler metals.
Some students build creative things; one student made a bicycle...	...and braze it with filler metal to join the pieces of copper. With practice, all of the joints should hold pressure.
Before testing their creations for leaks, students conduct a standing pressure test on the existing closed system. They pressurize it with a mix of refrigerant and nitrogen to determine if it has any leaks...
...and if it does not hold pressure, they use an electronic leak detector...
...to find the general area of the leak.	Soap bubbles are used to pinpoint the location of the leak.
Leaks can be difficult to detect; this is an important skill that the students must master.
Students braze their objects to the unit then pressure test to detect leaks.
Using his digital volt-ohmmeter, the student checks for shorts, opens and grounds before applying power.	Students also study the schematics of the various systems.
While one student connects his manifold set to the service ports, another student uses his digital voltohmmeter to determine if it is safe to apply power.