US Patent 12025322 Integrated recirculation pump for non-condensing water heater

A hot water circulation system comprises a water heater having a cold-water inlet and a hot water outlet. A water pump circulates water through the water heater to produce hot water. The hot water is circulated to a thermal bypass valve, which is configured to close when hot water contacts a heat activated seal. A bypass circuit is coupled between the hot water outlet and the cold water inlet of the water heater. The bypass circuit prevents hot water from circulating from the hot water outlet to the cold-water inlet when the thermal bypass valve is open and promotes circulating hot water from the hot water outlet to the cold water inlet when the thermal bypass valve is closed. Upon a temperature sensor sensing hot water entering the cold-water inlet, the water heater turns of the water pump.