R-Pro › Field cases › Air conditioning
AC Refrigerant Flow Noise — Shhh / Hiss / Water-Like Sound
Likely causes
Identify flow noise — normal vs abnormal
Check: Normal: brief 'shhh' right after OFF→ON (pressure equalization). Abnormal 1: continuous hiss = leak + audible gas escape. Abnormal 2: 'gurgle' like water = undercharge (evaporator two-phase imbalance). Abnormal 3: whistle = EEV/TXV oscillation or kinked tubing.
What to do: Normal needs no action. Hiss = trace leak then repair. Gurgle = trace leak, vacuum, recharge. Whistle = diagnose/replace EEV or fix kinked tubing. R-32 audible leak = ventilate immediately + remove ignition sources.
Educate user: brief 'shhh' is OK / continuous hiss/gurgle/whistle = report immediately. Audible R-32 leak = safety risk (flammable). Ventilate and shut down zone.
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
Open R-Pro →