Arkansas HVACR NewsMagazine May 2022

HVACR NewsMagazine May 2022

Tech News

reduce the chance of the nut spinning the tube when tightening.

When you’re ready to begin assembling everything, hold the flare to the mating surface and tighten the flare nut over the threads with your fingers. Stop once you get the flare nut finger-tight. Now, it’s time to b ring out your torque wrench. You’ll want to consult the manufacturer’s literature for the recommended torque specs based on the piping diameter. Adjust your wrench to reach the recommended torque (usually in ft-lbs) before you even touch the flare nut. When you use a torque wrench, only apply force to the handle; additional force elsewhere will result in a false reading (and inaccurate torque

applied to the flare nut). Tighten it down according to the torque wrench’s settings and the manufacturer’s specs. With your flare assembly all ready, you can move on to the leak testing and detection phase.

Testing for leaks with a nitrogen pressure test

A standing pressure test with nitrogen lets us see if the system leaks at an unacceptable rate. We can do a standing pressure test before even putting a unit into service, or we can use it to locate leaks on existing systems. You may also need to use a nitrogen pressure calculator when performing long-term tests, especially when you’re dealing with variable temperature conditions. HVAC School has a nitrogen pressure calculator on the “Calculators” page of our website or under “Tools” on the mobile app, shown to the right.