By incorporating the latest in heat exchanger technology and a modular design, the Simple Drainback System reduces the number of components associated with traditional drainback systems thus significantly reducing installation time and complexity. The system design eliminates the need for additional pumps, tanks, piping and hardware. The system arrives installation ready with the pump flange and the pre-wired controller fastened to the tank. Installation requires only four plumbing connections and one sensor connection. Once filled with water, the system is ready for years of maintenance free, reliable operation.