Thermo-siphon Type Hot Water Circulating System

Thermo-siphon Hot Water Circulating System Thermo-siphon hot water heating system.

A thermo-siphon hot water circulating system does not require a pump but relies instead on the principle that hot water rises.  In this type of system the water heater must be below the level of the fixtures to work.  

The piping from the water heater must rise from the water heater to the fixtures which must all be well above the water heater.  Hot water from the water heater rises into the hot water piping, circulates past the fixtures and flows back into the water heater at a much lower temperature.