The EHC 409R2B is a part of the Emerson Climate Technologies (ECT) Enhanced Heat Pump Defrost Control family. It is a Network defrost controller used in heat pumps and related applications, designed to provide optimal defrost while increasing compressor life and improving system performance. The 409R2B is made to support 4 distinct defrost cycles, and is capable of processing input signals from multiple sensors, with one additional output to provide reliable signal information. It offers an array of features, including electronic bypass, narrow pressure bands, temperature compensated operating pressures, self-configuring temperature sensors and intelligent control. It is compatible with a variety of HVAC systems, making it one of the most efficient defrost controllers in the ECT family.