Performance characteristics. Using zw series Copeland compressors, wide range operation. . Counterflow circuit layout, ensure subcooling refrigerant, effectively improve the heating efficiency, and low unit operating normally. Ultra-low temperature conditions to run at temperatures of -20 ℃ to work properly. Energy efficiency that does not solve the low temperature heating, energy efficiency, low common problem. With automatic antifreeze function, to prevent the pipe pumps and other components are cracking. . Cold under performance jumped, safe and reliable, a 10 ℃ lower heating capacity increased by nearly 20 percent, more suitable for cold regions.