... Multi-usage function 4.CE, ETL,EMC 75kw low temperature multifunction double source heat pump Wide range of applicationsCombine used air ... working conditionApply to -20 °C ~ 45 °C of ambient temperature, any weather ,day or night availableHigh efficient and energy savingWorking ... of hot water flow and air flow, compressor exhaust temperature, high and low pressure compressor, compressors flow and power ...