The Guardian DB is an indirect drain back solar water heating system designed to accommodate climates where freezing weather occurs more frequently. The solar storage tank and the solar collector(s) do not differ from the Guardian direct solar system, the only difference lies in the way that the water is processed through the solar collector(s). Rather than circulating your potable water directly through the solar.

collector(s) and back to the storage tank, your water is heated indirectly through a heat exchanger contained in the drain back tank. The Guardian DB utilizes two circulation pumps. One pump circulates water through the solar collector and back to the exchange/drain back tank. A second pump simultaneously circulates water from the solar storage tank into the exchange/drain back tank transferring the heat from the water that is being circulating through the solar collector(s) to your potable water. The system is freeze proof because all the water in the solar loop drains down into the small heat exchange/drain back tank when the solar circulation pump is turned off by the automatic controller. With no water remaining in the solar collector(s) or solar plumbing, no freezing of the system can occur. The indirect drain back solar system is the most efficient solar water heater design for climates that experience frequent freezing conditions.