Americool Portable Air Conditioners Alarm Codes Model; HPC-3000 / HPC-5000 / WPC-7000 / WPC-9000 / WPC-15000 Alarm Display: 1C Problem: Frost preven on sensor and Abnormal temperature sensor value Cause: Indoor heat exchanger temperature too low TH3 temperature sensor has a loose or broken connec on Corrective Action: Do not use the air conditioner if