... ,AW13B,AW15,AW15B,AW20,AW20BLow temperature air to water heat pump :AW10/L,AW13/LNormal air to water heat pump can work at above ... -10 degrees ,Low temperature air to water heat pump can work at -20 degrees.AW09,AW09B,AW12 ... double pipes or other types ) , repair easily;Air exchanger (Fan coil ) with hydrophilic coating ,higher coefficient of heat transmission than common;SIEMENS ...