... at above -10 degrees ,Low temperature air to water heat pump can work at -20 degrees.AW09,AW09B,AW12,AW12B, ,Power ... phase heat pumpON LINE SYSTEM is optionalDaily hot water pump: Wilo water pump is optionalElectric heater: 3KW ,6KW,9KW is optionalAIR TO ... ,TUV efficiency certification , Designed and Tested by Europe Standard EN14511,Factory Audit by Bureau Veritas , ISO9001;3.On line system reduce ...