... , connected by the water pipe, no connection with the refrigerant pipe, the length of water pipe can be longer or ... automatic defrost, automatic load regulation.[Environment protection] The use of refrigerant R410A, CO2, no pollution, no waste, environmental.Simple operationDot matrix LCD ... can apply to -25°C~45°Coutdoor temperature . 20kw R410a ETL certified double sounce heat pump project examples