Arkansas HVACR NewsMagazine May 2022

HVACR NewsMagazine May 2022

Tech News

Avoid moving the torch around too much when applying heat to the joint. Many inexperienced techs are afraid of burning through the base metal while brazing. As a result, they wave the torch too much and don’t get the base metal hot enough to draw the alloy into the joint. (Copper should be 1200- 1300 degrees and turn a dark or medium cherry red color before you apply the brazing rod.) To protect nearby valves, bulbs, and tubing insulation from heat damage, we can cover them in wet towels or heat-blocking putty (like Refrigeration Technologies WetRag).

Wait for the joint to cool off on its own for at least 20 seconds before applying a wet towel to it. If you apply a cold, wet towel too soon after the braze job, you may end up stressing the metal. After you cool the joint, you can apply a bubble solution and use a mirror to look for imperfections around the joint. You may notice some black scale or dried flux around the joint; clean that off with a rag. Once you’ve cleaned and cooled the tubing properly, you may begin preparing for your pressure test.

Finishing up a braze job

Leak preventive practices: proper flaring

When the alloy gets drawn into the joint, it will ideally create a nice seal around the joint. It doesn’t have to look like a perfect cap, but that’s what many people try to go for because it’s functional and looks nice.

We often have to make flares in the field, especially for ductless installs. However, flares are notoriously common leak points, so we have to look closely at our best flaring practices to ensure that we do all we can to prevent leaks.