Bubble solution is the simplest and one of the most sensitive pinpoint leak tests: brushed onto a flare nut, braze joint, service valve or Schrader cap, it grows bubbles or foam where gas escapes. Techs often find the area with an electronic detector first, then bubble it to confirm the exact spot. New installs are pressure tested with nitrogen and every joint is bubbled before evacuation.
Detector went off near the indoor coil, bubble it at every flare nut and the return bends.
Also heard as
- bubble test
- soap it
- bubble the joints
Related terms
Top off
To add refrigerant to a system that is low on charge without finding and fixing the leak.
Flowing nitrogen
Running a low flow of dry nitrogen through copper lines while brazing to keep oxide scale from forming inside.
Pull a vacuum
To evacuate a refrigeration system with a vacuum pump, removing air and moisture before charging.
Schrader valve
A spring-loaded valve core in a refrigerant service port, opened by the depressor in a gauge hose fitting.