Littelfuse 233P-1.5 PumpSaver Plus Single-Phase 230V 1/3 to 1.5 HPLittelfuse 233P 1. 5 PumpSaver Plus Production Description The 233P is a single phase pump monitor designed to protect single phase pumps from dry well, dead head, jammed impeller, rapid cycle, overvoltage and undervoltage conditions. The 233P protects 230 volt, 2 or 3 wire, 1 3 to 3hp pumps. A calibration adjustment allows the 233P to be calibrated to your specific pumping applications, thereby reducing the possibility of false or nuisance tripping.