The Solahart Heat Store Series II system is a large capacity storage vessel filled with heat transfer fluid, designed to be interfaced to a quantity of Solahart’s proven high-performance solar collectors. The system can provide hot water only or hot water in combination with floor heating and/or pool heating. The intelligent controller controls all active components of the system; from the amount of solar gain and supplementary boosting to regulating floor and pool heating. Additionally, the data from the controller can be logged and viewed locally or remotely. The system utilises a large capacity storage vessel filled with heat exchange fluid. Immersed in the fluid are copper coil are exchangers through which the potable water supply is circulated. As the potable water passes through the coils the stored energy within the heat transfer fluid is conducted through the copper providing instantaneous hot water. The tank is well insulated and the copper coils inside the closed circuit water provide ample hot water under high pressure with large flows. When the unit is in standby mode the heat exchange fluid drains down from the collectors and is stored in the main storage vessel. When the controller senses a preset temperature differential between the collector and the Heat Store, the system pumps the heat exchange fluid from the storage vessel into the collectors where the solar heating occurs. Once the system is completely filled, the controller will adjust the speed of the pump to ensure the maximum solar gain is achieved. When the system has reached its maximum temperature, or, there is no more solar gain possible, the system switches back to standby mode, allowing the heat exchange fluid to drain back into the storage vessel. This ‘drain back’ process eliminates and risk of overheating on days of high radiation days and/or low hot water demand, and also provides protection from the freezing of the collectors during winter.