Solar water heater control and protection system

摘要

This disclosure relates to a control and protection system for a solar water heater apparatus, which incorporates a temperature differential controlled variable speed drive for the circulating pump, and a drain down valve which is responsive to low collector temperature, high tank temperature and also to power loss, to serve in combination as a device to optimize efficient energy collection while also protecting the tank against overheating and further protecting the collector panel against freeze-up even during periods of power loss.