... 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 optional ON ... Bureau Veritas , ISO9001;3.On line system reduce your service cost sharply ;4.World famous parts , quality is assured;DAIKEN OR ...