Find a refrigerant leak

Tools: Electronic detector rated for this refrigerant (A2L-rated on R-32 / R-454B) · Bubble solution · Nitrogen + regulator for a standing test · Mirror, flashlight, USB inspection camera · Core tools and extra schraders

1. 1. Confirm it is actually a leak

   Weigh / clock the history. Standing nitrogen test if you already recovered. A 3-ounce winter loss on a 6-lb 410A is not ‘just seasonal.’ Ice, oil spots, and a low-charge chart with high SH are the usual tell.

   Expect: A reason to hunt — not a ritual sniff on every PM.

   If not: If the weight is on the plate and SH/SC are on the chart, you do not have a leak call.

2. 2. High-probability joints first

   Schraders and caps, service-valve packing, braze joints you or the last tech made, reversing-valve sweat, indoor coil hairpins, the liquid-line drier, and the crimp on a factory process tube. Soap with the system at standing pressure or on a nitrogen charge. Electronic at the base of the cabinet and along the lines with a slow pass — HVACR School: do not wave it like a wand.

   Expect: A repeatable hit you can soap.

   If not: No hit at the outdoor → indoor coil, evap hairpins, and the flare nuts on a ductless. Pull the indoor coil if the nitrogen test fails and the outdoor is dry.

3. 3. Repair, test, evacuate, weigh back in

   Recover. Repair (braze with nitrogen, or replace the core / valve). Nitrogen standing test. Vacuum with decay. Weigh in the nameplate charge — do not top off a leak. Replace the drier on an opened 410A / A2L POE system.

   Expect: Standing test holds. Decay holds. Nameplate weight back in.

   If not: A second loss next week is the joint you did not see — usually the indoor coil or a cracked vibration loop.

• Dye contaminates POE and some electronic detectors. If you use it, write it on the ticket.
• A leaking schrader is a 4-minute fix that gets skipped when someone is hunting a coil.