... 2.Punctual delivery 3.Short circuit protection PCBA Design for Heat Pump Water Heater 1. Auxiliary power function, multiple protection: the bipolar ... the heating temperature, timing heaing time, input water leavel, timing input water time.4. Water level detecton, AC/DC valve control input ... jump optional, waterproof protection, circulating pump failure detection. PCBA Design for Heat Pump Water Heater