Aquavar AB2S010 is a 115 V, 1‑HP variable‑speed pump controller (Goulds Water Technology) that adjusts motor speed to maintain constant pressure and includes an integral pressure sensor. Common failure points in this class of controllers are power‑supply overvoltage or sag, degraded MOSFETs causing overheating, faulty pressure transducer input, and blown fuse/thermal cut‑out tripping due to motor stall. First‑check diagnostics: verify 115 V AC at the inlet terminals and confirm the controller’s internal supply voltage (≈12–15 V) is within spec; inspect the pressure sensor cable for continuity and correct signal level; review any stored fault codes or LED status indicators on the unit, then perform a visual check of MOSFETs and fuses for burn marks.[oss-gpt-20b]