... ,with or without buffer water tank for option Commercial Air Source heat pumps Features:1. Base frame and extenal ... overheating,overload,antifreezing,phase order,discharge temp,etc. 7. Air exchanger(Fins-coil)with hydrophilic coating,Automatic defrosting function ... General testing and operational test carried out for every unit before package in the factory.Specifications: 38kw Air Source Heat Pumps